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Have you heard the bull**** claim that "renewables are great but they aren't enough"?

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-12-10 04:02 PM
Original message
Have you heard the bull**** claim that "renewables are great but they aren't enough"?
This is a common bit of misinformation that swirls around the public consciousness, perverting the ability of the public to make informed choices on how we proceed to address our energy security and climate change needs. This is a detailed analysis matching real world demand and the known operational profile of renewable energy sources. It clearly shows that claims such as "renewabes can't do it" or "renewables aren't enough" are nothing but balderdash and poppycock.

These false beliefs that are being nurtured by political and economic forces that stand to lose power and money if we focus our efforts on the renewable, sustainable solution to our energy issues.

Equally important is the fact that not only CAN renewables do the job, but they can do it for less money, more reliably, with far fewer external costs, and much much lower risks than the only other non-carbon contenders - coal with carbon capture/sequestration and nuclear power.

The claim is NOT being made that this would be an easy task. Nor is the claim made that the modeling in the paper is perfect representation of all geographic areas and the specific resources that would be available to meet demands in those areas; for example, there will be areas where wave/current/tidal or biomass are more important than solar, or where storage options like pumped hydro and compressed air storage are more appropriate than standard hydro.

What the paper does demonstrate is the fallacy of the idea that renewable energy resources are not up to the task. We have a wide range of technologies sitting on the shelf available to meet demand and it is good to be aware of their potential.

Matching Hourly and Peak Demand by Combining Different Renewable Energy Sources
A case study for California in 2020



Graeme R.G. Hoste
Michael J. Dvorak
Mark Z. Jacobson

Stanford University
Department of Civil and Environmental Engineering
Atmosphere/Energy Program


Abstract
In 2002 the California legislature passed Senate Bill 1078, establishing the Renewables Portfolio Standard requiring 20 percent of the states electricity to come from renewable resources by 2010, with the additional goal of 33% by 2020 (California Senate, 2002; California Energy Commission , 2004). More recently, some legislative proposals have called for eliminating 80% of all carbon from energy to limit climate change to an acceptable level. At the passing of the 2002 California bill, qualifying renewables provided less than 10% of Californias energy supply (CEC, 2007). Several barriers slow the development of renewables; these include technological barriers, access to renewable resources, public perceptions, political pressure from interest groups, and cost, to name a few. This paper considers only one technological barrier to renewables: integration into the grid.

Many renewable resources are intermittent or variable by natureproducing power inconsistently and somewhat unpredictablywhile on the other end of the transmission line, consumers demand power variably but predictably throughout the day. The Independent System Operator (ISO) monitors this demand, turning on or off additional generation when necessary. As such, predictability of energy supply and demand is essential for grid management. For natural gas or hydroelectricity, supplies can be throttled relatively easily. But with a wind farm, power output cannot be ramped up on demand. In some cases, a single wind farm that is providing power steadily may see a drop in or complete loss of wind for a period. For this reason, grid operators generally pay less for energy provided from wind or solar power than from a conventional, predictable resource.

Although wind, solar, tidal, and wave resources will always be intermittent when they are considered in isolation and at one location, several methods exist to reduce intermittency of delivered power. These include combining geographically disperse intermittent resources of the same type, using storage, and combining different renewables with complementary intermittencies (e.g., Kahn, 1979; Archer and Jacobson, 2003, 2007). This paper discusses the last method: integration of several independent resources. In the pages that follow, we demonstrate that the complementary intermittencies of wind and solar power in California, along with the flexibility of hydro, make it possible for a true portfolio of renewables to meet a significant portion of Californias electricity demand. In particular, we estimate mixes of renewable capacities required to supply 80% and 100% of Californias electricity and 2020 and show the feasibility of load-matching over the year with these resources. Additionally, we outline the tradeoffs between different renewable portfolios (i.e., wind-heavy or solar-heavy mixes). We conclude that combining at least four renewables, wind, solar, geothermal, and hydroelectric power in optimal proportions would allow California to meet up to 100% of its future hourly electric power demand assuming an expanded and improved transmission grid.



To download entire report click on Report on matching hourly and peak demand by combining different renewables (pdf) at
http://www.stanford.edu/group/efmh/jacobson/susenergy20...

You may also enjoy some of the other papers at that link. They are all open source documents free to download. Particularly recommended is E&ES article on ranking energy solutions to global warming, air pollution, and energy security.
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DCKit Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-12-10 04:06 PM
Response to Original message
1. They may as well be saying "It's not easy, so why bother?" n/t
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txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-12-10 06:27 PM
Response to Original message
2. By combining all of the renewable sources available to us
That is the only logical path to follow anyway. We are in the predicament we are in today because we allowed the power companies to focus on one source, coal, far too much. By allowing coal to dominate our energy production we have made its dilatory effects worse while simultaneously making it harder to switch to alternatives than had we limited coal's usage to no more than, say, 25% of our energy generation. We cannot allow the same thing to happen with renewables.

For a secure energy future, therefore, we should split power generation between all of the renewable sources at our disposal to avoid a situation of excessive dependence on any one of them in the future.

Solar PV - susceptible to effects of shade blocking even a portion of one module, future volcanic activity would reduce its output.
Solar Thermal, aka Concentrated solar Thermal - cloudy days reduce output, same problem with volcanic clouds
SSPS - Space-based Solar Power Systems can receive sunlight 24/7 and beam it down to receivers on the ground, no variability but possible disruption of power due to weather phenomenons (more testing needed), downside is it's expensive
Wind - seasonal variation, "doldrums," hurricanes can damage many of them
Geothermal electrical generation - stable power generation with no variability (that's good), possibly limited to geologically stable regions and current hot spots of geothermal activity
Tidal energy - limited geographic areas where tidal flows can be harnessed
Wave energy - as long as we have a moon there will be waves, downside is large area needed to produce usable amounts of electricity

Geothermal heating and cooling - can replace both heaters and air conditioners in residential and commercial buildings, may be used for hot water as well, not seasonally variable
Solar Water Heaters - self explanatory, reduced effectiveness in winter required a supplemental heat source but still pays for itself in savings

The grid needs to be upgraded with High Voltage DC transmission lines from the areas where renewable energy is generated to the populated areas and/or to interconnect with the AC transmission grid where appropriate.

In short, renewable energy can provide 100% of the energy we need as a society. To reduce the cost of getting off coal and oil we also need to improve efficiency in our buildings, gadgets, vehicles, lighting, and just about every thing else. I haven't seen anybody calculate the savings but there will be a payoff for improving efficiency (such as insulating your home and caulking any gaps or cracks) via a multiplier effect, e.g., saving 20% on a/c usage reduces summertime electricity needs by "X" amount.

Buildings - insulation, sealing gaps/cracks, triple-glazed windows w/ low-E coating, passive solar
Gadgets - reducing vampire power which some calculate as taking up 5% to 10% of your electric bill
Vehicles - electric vehicles are 5 times as efficient as gasoline or diesel vehicles
Lighting - 2012 will be the year that LED lighting takes off as mass production brings prices down, doable now if money is no object
Televisions - LED TV will be the next big thing, look for prices to begin to decline soon (currently too pricey)

It seems that it's a recent focus for electronics makers to consider power usage, with the exception of laptops and portable devices perhaps, but all manufacturers need to continue to look for ways to reduce power consumption in all their products.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-12-10 09:08 PM
Response to Original message
3. Nothing succeeds like success
Equally important is the fact that not only CAN renewables do the job, but they can do it for less money, more reliably, with far fewer external costs, and much much lower risks than the only other non-carbon contenders - coal with carbon capture/sequestration and nuclear power.
===============================

Well nobody is stopping you - go do it!!

If the renewable industry wants to be taken seriously;
they just have to go out and do the job. Give people
the power they demand, at the time they demand, for
the price they are willing to pay, and do it safely
and without pollution - then the world will beat a
path to your door.

As we always say, "Nothing succeeds like success".

However, if you expect someone else to foot the bill,
and you only want to provide power in the daytime,
or you need to have the ratepayer pay double, or...
whatever - then I'm not interested.

Nobody is preventing the renewable industry from
doing the job they say they can do. If some power
company makes renewables the cornerstone of their
power system - then fine - renewables are a player.

Until they do something beyond toy demonstrations
of 1 or 2 Megawatts; I don't see why anyone should
give them the time of day.

Dr. Greg
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Kringle Donating Member (411 posts) Send PM | Profile | Ignore Sun Sep-12-10 10:12 PM
Response to Reply #3
5. hey Europe, go do it
you don't need the US's permission
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Nihil Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-13-10 07:22 AM
Response to Reply #5
7. Hey Razzleberry, he's not in Europe
:eyes:
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Kringle Donating Member (411 posts) Send PM | Profile | Ignore Mon Sep-13-10 09:31 AM
Response to Reply #7
9. the US, can't be expected to go first at everything
we can't afford it
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-15-10 02:52 PM
Response to Reply #9
13. Renewables represented 62% of Europes new capacity in 2009.
Renewables Account for 62 Percent of the New Electricity Generation Capacity Installed in the EU in 2009

ScienceDaily (July 5, 2010) The "Renewable Energy Snapshots" report, published by the European Commission's Joint Research Centre, shows that renewable energy sources accounted for 62 percent of the new electricity generation capacity installed in the EU27 in 2009. The share rose from 57 percent in 2008. In absolute terms, renewables produced 19.9 percent of Europe's electricity consumption last year.
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OnlinePoker Donating Member (837 posts) Send PM | Profile | Ignore Wed Sep-15-10 04:42 PM
Response to Reply #13
14. If you want to read the actual report, the link is below
http://re.jrc.ec.europa.eu/refsys/

The report is the second item down on the right under "NEWS"
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sat Sep-18-10 04:33 PM
Response to Reply #13
24. Yeah! - let me know...
Yeah! Let me know when renewables ( exclusive
of hydro ) comprise 1% of the installed capacity in Europe.

Dr. Greg
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muriel_volestrangler Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 02:14 PM
Response to Reply #24
114. That would be 'now'
Overall, hydropower still makes up the single largest share at 11.6% of Europes total electricity consumption, followed by wind (4.2%), biomass (3.5%) and solar (0.4%).

http://www.energyefficiencynews.com/i/3198/
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Nederland Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-13-10 11:38 PM
Response to Reply #3
12. +1
I totally agree. Over the next five years we should see who has created the most new global power generating capacity: nuclear, solar, or wind. I say whoever comes in last gets cut from the game, no excuses. It's time to put up or shut up.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Oct-03-10 10:47 AM
Response to Reply #12
138. Why does it have to be "new"
I totally agree. Over the next five years we should see who has created the most new global power generating capacity: nuclear, solar, or wind. I say whoever comes in last gets cut from the game, no excuses. It's time to put up or shut up.
=========================================

Why is the metric based on "new" capacity?

For example, we are not building much in the way of new
hydro-electric facilities, since so many people don't like
dams. In fact, some want to get rid of the dams we have;
the Hetch Hetchy dam for example. But hydroelectric produces
about 9% of our electricity.


Renewables such as wind and solar are less than 1%.

Suppose renewables double their capacity from 1% to 2% and
no new hydroelectric dams were built. Under your rules,
hydroelectric had 0% new capacity, and would lose to
renewables.

However, even with no increase, hydro would still be producing
many times the amount of energy as renewables, so it would be
stupid to cut hydro.

The point is that renewables are WAY BEHIND everything else;
and for good reason; so I wouldn't cut anything that was still
producing more energy than renewables even if there were no increase.

Renewables are way behind everything else; so we should give everything
else a pass until renewables catch up.

Dr. Greg
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joshcryer Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-12-10 09:52 PM
Response to Original message
4. The only bullshit claim I've heard is that renewables have a chance in hell at averting catastrophic
...climate change.
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Christopher Calder Donating Member (61 posts) Send PM | Profile | Ignore Mon Sep-13-10 09:23 PM
Response to Reply #4
10. Your "math" is faulty
U.S. vegetation collects less than 0.1% of solar energy hitting the U.S. The crops we produce collect half of that amount. Collecting solar energy and using it efficiently are not so easy. The proof is in the cost.

Solar Thermal @ 25.66 cents per kWh not including the cost of needed energy storage and/or back-up systems (31.2% CF) - Carbon free, extremely low CF, extremely large ecological footprint, not cost effective due to high construction cost and a CF even lower than wind power.

Solar Photovoltaic @ 39.61 cents per kWh not including the cost of needed energy storage and/or back-up systems (21.7% CF) - Carbon free, extremely low CF, extremely large ecological footprint, very high construction cost, cannot be upgraded after manufacture, and short lifespan. Solar photovoltaic panels are absolutely not cost effective for large scale power production.

If we go to 100% renewables or even 50% renewable, most people will not have enough money left at the end of the month to eat. Few will be able to send their children to college because all their funds will go to higher electricity bills. The renewable energy cult is the most destructive false religion in the world today. Biofuels already have a gigantic body count in the millions. Wind and solar are not a positive investment. They are weakening us, because they are so inherently inefficient and unreliable. Hydroelectric works, but there are few opportunities left for big dam construction. Thorium power is our only hope, and it is meltdown proof, clean, does not produce long lived radioactive waste, and can produce electricity for less than the cost of coal or natural gas, and it is carbon free.

SEE: http://thorium.50webs.com/ - thorium power

SEE the true math of renewable energy schemes:

http://phe.rockefeller.edu/docs/HeresiesFinal.pdf
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Christopher Calder Donating Member (61 posts) Send PM | Profile | Ignore Mon Sep-13-10 12:42 AM
Response to Original message
6. See Germany's renewable energy failure!
Germany throwing money away on worthless symbolic wind and solar projects that produce nothing but higher electric bills!

HEADLINE SENTENCE

"German households already pay more than twice as much for electricity as US households, while German industry pays about 250% what its US counterparts pay."

Note the article states that photovoltaic cells in Germany have a Capacity Factor of under 10%! Holy Cow! Capacity Factor for wind power in Germany is just 21%! The Germans sure are throwing allot of money down the drain for worthless green symbolism. Nuclear power plants typically have a Capacity Factor of 90%. A power plant with a Capacity Factor of 90% generates energy at its rated capacity an average of 90% of the time during a given year. The ideal power plant would have a Capacity Factor of 100%, meaning it could output energy at full power 100% of the time. As capacity factor drops, electricity grid efficiency drops, and real-world costs increase. The high cost of wind and solar construction, plus their ultra low Capacity Factor, and the unpredictability factor of wind makes them monuments to human foolishness, and a very expensive fiasco indeed.
_______________________________________________________
Germany's Nuclear Bridge -Geoffrey Styles - http://energyoutlook.blogspot.com/

Since I've been taking potshots at German energy policy recently, I was pleased to see that it appears the country's government is nearing a reasonable compromise concerning nuclear power, which accounts for 22% of the electricity generated in Germany. The Financial Times reported yesterday that the CDU/FDP coalition is likely to propose extending the life of the country's reactors by 12-15 years, in order to give renewable energy sources more time to ramp up. Yet while the extension makes enormous sense from the perspective of emissions and energy security, I'm puzzled by the plan's implicit assumption that nuclear power is valuable only as a bridge to more renewable energy, rather than as a key part of any future, low-emission energy mix.

In 2007 Germany's 17 reactors generated 140 billion kWh of electricity. By comparison, all renewable sources amounted to just over 100 billion kWh, with only 3 billion of that coming from the country's highly-subsidized solar photovoltaic (PV) installations. All of these reactors will reach the limits of the their currently-allowed 30-year service lifetimes by 2020, when they are required by existing law to be shut down, and all have provisional shutdown dates within the next few years. The problem is that the incremental growth in renewable electricity required to replace all of these plants does not seem feasible within that timeframe, despite its impressive expansion so far.

Replacing just the net output of those reactors would require total renewable generation to expand by roughly 150%, though much of that expansion would by necessity depend on a much smaller fraction of the renewable power base. Wind currently supplies 6.5% of generation and continues to grow steadily. PV capacity has more than doubled since 2007, from 4,000 MW to 9,800 MW last year, though that still results in a contribution of only around 1% of generation, partly due to scale and partly to Germany's low solar insolation. Wind and solar output would have to quadruple to fill the kWhs supplied by nuclear power, plus their current part of the mix. This challenge is compounded by the problems of intermittency and low output vs. nameplate capacity of both of these sources. In 2007 the calculated capacity factor for Germany's wind turbines was just 21%, while PV was under 10%. So not only would these sources have to expand by a multiple of the capacity lost from idled nuclear reactors, but much of the incremental output would have to be stored, in order to time-shift it to match demand--combined with time-shifting demand to match the variable and cyclical output from these sources. Power from other renewable sources such as biomass, waste and hydro is much more compatible with normal demand patterns, but more difficult to expand quickly and overcome resource limitations.

Most Germans are intensely practical. That German practicality is in my genes and upbringing, part of which was spent in Germany. I speak the language and know the people fairly well, yet it remains a mystery to me that Germans would choose to pit these two complementary categories of electricity generation against each other, rather than aligning them cooperatively to replace high-carbon coal and natural gas that is largely imported from Russia--hardly the world's most reliable supplier. The answer appears to reside in coalition politics (in both major groupings) and green ideology, the price of which seems likely to rise sharply. German households already pay more than twice as much for electricity as US households, while German industry pays about 250% what its US counterparts pay, and I can only guess at the comparison to Chinese energy costs. Taking large, fully-depreciated baseload power sources out of the national mix will only amplify those disparities. I'd be very surprised if Germany didn't choose a course that hews back towards practicality in the long run.

Geoffrey Styles
----------------
Also see "The Renewable Energy Disaster" at: http://renewable.50webs.com/

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madokie Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-13-10 07:29 AM
Response to Original message
8. I agree with this
Recommended too but still at a big fat 0
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Nederland Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-13-10 11:34 PM
Response to Original message
11. Yawn...
...another "study".

When will renewable backers stop writing words and start building things that, you know, actually generate power? Nobody is stopping you, so what's the problem?

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AtheistCrusader Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Sep-17-10 03:31 PM
Response to Original message
15. Cognitive dissonance
"Equally important is the fact that not only CAN renewables do the job, but they can do it for less money, more reliably, with far fewer external costs, and much much lower risks than the only other non-carbon contenders - coal with carbon capture/sequestration and nuclear power.

The claim is NOT being made that this would be an easy task."


It's supposedly cheaper, more reliable, and less risky.

Then why won't it be an easy task?
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Sep-17-10 04:25 PM
Response to Reply #15
16. The scale of the undertaking is huge.
This means we need to devote huge resources to accomplishing it in a timely manner. A good parallel is the move to a war footing after Pearl Harbor, if we matched that effort we could accomplish the goal in 10 years.

A second order obstacle is the diversion of funds to non-performing technologies by entrenched political and economic interests. Madates for biofuels encouraged by the ag/petroleum industries, and support for nuclear/carbon capture and storage by the Halliburtons, utilities and minerals mining companies are a couple of examples.

A distributed renewable grid takes control of the energy supply away from those bottleneck industries and turns it into an endeavor that is "commoditized". For example, instead of paying for the lifetime of energy it produces (30-40 years), when solar panels become a commodity through market saturation and economic competition, they will be sold for the cost of production plus a small profit markup. The entrenched energy industry simply doesn't like that and since the total value to them over the next 100 years is on the order 1 quadrillion 312 trillion 200 billion in today's dollars, they are extremely motivated to keep it from happening.

No, I'd never say the transition to a noncarbon energy infrastructure is easy because like any other major shift in infrastructure, it isn't.


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AtheistCrusader Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Sep-17-10 09:21 PM
Response to Reply #16
17. Washington State is over 75% renewable.
We didn't need some unique grid to accomplish it. I think you'll find we don't need one for nation-wide renewable power.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Sep-17-10 09:54 PM
Response to Reply #17
18. Unfortunately I'm very sure that we do need the grid upgraded.
Localities, neighborhoods and homes can often be largely self sufficient, but distribution of the resources by nature simply isn't adequate. The amount we will *depend* on the grid, however, will be dramatically reduced.
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XemaSab Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-18-10 10:14 AM
Response to Reply #17
20. Washington State has massive hydropower projects
Most hydropower resources in the US have already been developed.

That free lunch done got ate. :P
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AtheistCrusader Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-18-10 03:23 PM
Response to Reply #20
21. There are more, plus tidal.
We could build a dam similar to the Hoover, in Alaska, and take it off hydrocarbons completely. Transmission lines will be expensive, but can be done. Sell power to Canada too, weakening the need to export oil. A lot of the remote places in Alaska that will be difficult to power, are only inhabited because oil drilling pays for it/needs it.

Places like ND will be another story. Mostly wind/solar. And we can backstop that with nuclear. Phase out hydrocarbons completely, and make nuclear a third tier, or backup power, burning off all our old warheads. Win win win.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 01:51 PM
Response to Reply #21
29. Good Luck
We could build a dam similar to the Hoover, in Alaska, and take it off hydrocarbons completely.
====================================================

Good Luck attempting to get more dams built with opposition from
the environmentalists. They don't want more dams built. They
actually want to remove some of the already build dams.

For example, in California we have the group that wants to
"restore" Hetch Hetchy. They want to tear down the Hetch Hetchy
dam and restore the valley to its original condition.

San Francisco and the Bay Area can look for another source of
drinking water and another source of power.

Dr. Greg

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OnlinePoker Donating Member (837 posts) Send PM | Profile | Ignore Sat Sep-18-10 04:03 PM
Response to Reply #20
23. Not only that, but there are serious moves to take down some of the Columbia river dams.
This will mean a big drop in power generation.
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AtheistCrusader Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 04:38 PM
Response to Reply #23
45. Over my dead body.
At least until we have other renewables online, generating power, to replace it.
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4dsc Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-18-10 07:22 AM
Response to Original message
19. Renewables will not replace OIL!!
There I said it and that's what the real problem is in the future. Most renewable are for power generation and will not replace oil. Pretty simple when you think about it.

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-18-10 04:03 PM
Response to Reply #19
22. Yes, they will.
You having "said it" doesn't make your claim true. You may not understand how it is going to happen, but that is because you haven't devoted sufficient study to the topic.

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4dsc Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-18-10 06:54 PM
Response to Reply #22
25. You don't know what your talking about here
not to mention you cannot even tell us which so called renewable would be able to replace oil on a barrel to barrel basis. Not to mention that all so called renewables are dependent upon oil to make. Your lost on this subject.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-18-10 08:32 PM
Response to Reply #25
26. I guess the past 8 years of post grad level study have been wasted then.
Edited on Sat Sep-18-10 08:33 PM by kristopher
Of course, the alternative explanation is that YOU have no idea of how our energy system functions nor of how to analyze the alternatives that are available.

For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
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4dsc Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-18-10 11:23 PM
Response to Reply #26
27. you're a waste alright.
All that education and you're still an idiot when it comes to peak oil and its ramifications. But I see you didn't answer my statement about the dependence on oil of your so called alternatives. Not to mention the fact that they all needs replacing in the coming decades when oil shortages are an every day life.

But you are talking about energy production and I am talking about oil. Tell me they are not two different subjects here.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 02:13 PM
Response to Reply #27
32. You don't understand that "oil" is a form of "energy production"?
Your opinions are based on total ignorance of the topic.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 02:41 PM
Response to Reply #32
33. Ever hear..,.,
Your opinions are based on total ignorance of the topic.
====================================

Ever hear the story about the pot and the kettle...?

Dr. Greg

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NNadir Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 11:22 AM
Response to Reply #26
28. I very much doubt that there is a SCIENCE graduate school where complete ignorance of
Edited on Sun Sep-19-10 11:48 AM by NNadir
the second law of thermodynamics is allowed to pass unnoticed.

If there is one, it's probably at a Bible University or something of that ilk.

I also note that post graduate courses in Byzantine history do not qualify anyone to discuss energy.

I would also seriously suggest that anyone with post graduate study would understand that the scientific literature consists of a far broader perspective than the babble of "Mark V. Jacobsen," God.

Anyone who has taken a science course at an undergraduate level in a remotely respectable college or university would be able to read this table, which comes after 50 years of exposition of the ridiculous theory that "renewables can save, not only us, but the car CULTure," and figure out if the theory agrees with the experiment:

http://www.eia.doe.gov/cneaf/solar.renewables/page/trends/table1.html

Also, it's very clear to anyone who has even the remotest modicum of scientific training that if theory clearly does not agree with experiment, the theory is thrown out.

Have a nice day, taking up space, wherever you take up space.

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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 02:11 PM
Response to Reply #28
31. You got that right.
I very much doubt that there is a SCIENCE graduate school where complete ignorance of
the second law of thermodynamics is allowed to pass unnoticed.
====================================

Boy you got that right. It demonstrates an APPALLING lack of
understanding of the 2nd Law. I would not expect a high school
student who has taken high school physics to be THAT ignorant.

All his castles of "energy dreams" are built on a weak foundation;
an abject IGNORANCE of the Laws of Physics.

Why would anyone listen to the opinions of one such?

Dr. Greg
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 03:06 PM
Response to Reply #28
34. One wonders what's next...
I very much doubt that there is a SCIENCE graduate school where complete ignorance of
the second law of thermodynamics is allowed to pass unnoticed.
=========================================================

One wonders what's next. Perhaps we will be treated to reports of
solar power plants that put out electricity, the energy content of
which exceeds the energy of the solar influx. Maybe we will hear
about solar plants that work off the energy of starlight at night...

Perhaps we will hear about wind turbines that recover more energy
in electricity and / or mechanical work than was in the kinetic
energy of the air in the first place.

If someone is abjectly ignorant of the 2nd Law of Thermodynamics;
perhaps they are just as ignorant of the 1st Law of Thermodynamics.

Dr. Greg



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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 02:00 PM
Response to Reply #26
30. 8 years of WHAT - certainly NOT science and engineering.
Edited on Sun Sep-19-10 02:22 PM by DrGregory
For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics or look at the following courtesy of
the Physics Dept at Georgia State University:

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html

Quoting:
"Second Law of Thermodynamics: It is impossible to extract an amount of heat QH
from a hot reservoir and use it all to do work W . Some amount of heat QC must
be exhausted to a cold reservoir. This precludes a perfect heat engine."

QC is the "waste heat" that has "no purpose".

If people are going to discuss energy intelligently, then they
should AT LEAST learn the ELEMENTARY BASICS of the physic of energy.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 03:14 PM
Response to Reply #30
35. Another sample of your "MIT PhD physicist, I work at a National Lab" knowledge?
Edited on Sun Sep-19-10 03:27 PM by kristopher
You wrote:
For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg



Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 03:45 PM
Response to Reply #35
36. He's hit rock bottom and begun to dig...
Edited on Sun Sep-19-10 03:47 PM by DrGregory
So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.
===============================================

More demonstrated IGNORANCE of the Laws of Thermodynamics;
specifically the 2nd Law.

Evidently he doesn't know the difference between the potential energy
in a fuel and the thermodynamically "available" energy in work.

That kilowatt-hour ( sic he said "kilowatt" which is a power; what we use / waste is
actually a kilowatt-hour, a unit of energy. ) is a unit of energy that contains
no entropy. Therefore, there is ZERO mandate by the 2nd Law of Thermodynamics
for the expulsion of waste heat. We don't have any entropy to expel, so we don't
have to exhaust any waste heat to carry away the entropy.

However, the case is different with the gallon of gasoline. When we burn the
gasoline, we WILL have both heat AND entropy. Therefore, we need to expel
waste heat to carry away the entropy.]

Kristopher; you should either LEARN some science and physics so you can talk
about energy and energy policy INTELLIGENTLY; or you can keep doing what you
have been doing. Your choice.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 03:59 PM
Response to Reply #36
38. ROFLMAO
The fact that you are a total fraud was just demonstrated conclusively - again. That's about 8 or 10 times in less than a month.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 04:03 PM
Response to Reply #38
40. Name calling?
Edited on Sun Sep-19-10 04:04 PM by DrGregory
The fact that you are a total fraud was just demonstrated conclusively - again. That's about 8 or 10 times in less than a month.
=====================

The fact that you can't REFUTE what I say and just resort
to name calling; I interpret as TOTAL CONCESSION.

If I were wrong, you would have been able to say what
physics laws my statements violated.

In case you haven't noticed; that's what I'm doing to you.

However, since ALL my statements are on sound physics ground;
and I even gave you a link to a university physics department
that backed me up - I have nothing to fear from the likes of you.

You can quote chapter and verse all you want; but next time show
us that you UNDERSTAND what you've quoted.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 04:12 PM
Response to Reply #40
42. That isn't name calling, it is simply stating the fact that you clearly do not posses
Edited on Sun Sep-19-10 04:12 PM by kristopher
... the education and expertise you claim.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 05:01 PM
Response to Reply #42
48. The fact...,
... the education and expertise you claim.
===========================================

I know the truth that I DO have the degree and
title to which I claim.

The fact that you don't recognize that fact
pleases me no end. It is just further proof
that when you see good science that you don't
recognize it.

It only serves to reinforce my opinion of you.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 05:23 PM
Response to Reply #48
52. .
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 06:40 PM
Response to Reply #52
67. I believe I have answered that.

I believe I have answered those posts.

I said "IF NOT FOR" the Stephan Boltzmann
re-radiation the Earth would heat up; and
what does Muriel do - uses the Stephan Boltzmann
law. That's why the temperature is calculated
from the 4th root.

Can people parse logical statements here?

One cites a premise to a statement, "IF NOT FOR"
that means without this premise, the following
would be true. Then people use the EXCLUDED
premise to prove the statement "wrong".

That is saying EXACTLY the same thing. Does anyone
understand the phrase "IF NOT FOR"??

Dr. Greg

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bananas Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-26-10 05:33 AM
Response to Reply #67
87. Your answers are grossly insufficient (to be polite).
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-26-10 05:21 PM
Response to Reply #87
89. Only to those...
Edited on Sun Sep-26-10 05:21 PM by DrGregory
Your answers are grossly insufficient (to be polite).
=============================================

Only to those that are not learned in science.

I stated, correctly, that a portion of sunlight
is reflected. However, the majority of the energy
is re-radiated as per the Stephan-Boltzmann law.

That re-radiation is a major component of the Earth's
heat balance. I considered a hypothetical case in
which "magically" the Stephan-Boltzmann re-radiation
were turned off.

So we had an influx of sunlight, with about 10% reflected.
That left 90% of the influx "unbalanced". There was no
sink or loss term to counter-balance 90% of the influx
in the Earth's heat balance equation.

So what would happen IF the Stephan-Boltzmann radiation
were turned off. The Earth would heat up. After all,
if one understands the Greenhouse Effect - the CO2
in the atmosphere is blocking some of this re-radiation.

What if something wasn't just blocking part of the
re-radiation, but the whole thing, that is all the
re-radiation were turned off. We would have an
EXTREMELY bad Greenhouse Effect - a "runaway"
Greenhouse Effect.

When would that runaway terminate? It would terminate
when the Earth reached the temperature of the energy
source driving the heat up. That is you can't get
energy from something that is colder than you are.
So that would be the photosphere of the Sun.

Of course, one can't turn off the Stephan-Boltzmann
re-radiation; so the extreme temperatures don't
happen in actuality.

Dr. Greg

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bananas Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 06:34 PM
Response to Reply #89
95. No, you stated, incorrectly, that "A typical landscape REFLECTS about 90% of the suns energy."
You just wrote:
I stated, correctly, that a portion of sunlight
is reflected. However, the majority of the energy
is re-radiated as per the Stephan-Boltzmann law.


No, as muriel_volestrangler pointed out:
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=256645&mesg_id=258337

What you did was try to deflect from your ridiculous claim of 90% of the radiation from Earth being being reflected from a typical landscape, which started off the discussion about absoorption and reflection. You said "A typical landscape REFLECTS about 90% of the suns energy".


You made two very wrong statements in your post which started this discussion:
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=256645&mesg_id=256760

Also the
argument that the solar proponents give that the sunlight falls
there anyway is false.

A typical landscape REFLECTS about 90% of the suns energy.



You used that wrong number several times in the rest of that post.
If you had meant "re-radiates" instead of "REFLECTS", you would have used the right numbers in the rest of your post, and you would have come to the correct conclusion that the solar proponents are right.
Because you had the wrong numbers, you came to the wrong conclusion.

Here is a partial correction of that post,
using strikeouts and boldface to indicate the corrections:

Also the
argument that the solar proponents give that the sunlight falls
there anyway is false true.

A typical landscape REFLECTS about 90% 20% of the suns energy.
Only 10% About 80% is absorbed and re-radiated as heat.
A PV plant will absorb 100% of the energy if it
is efficient < black in color >, and will convert about 20% to
electricity and discharge 80% as heat.

So if we take a piece of land with 100 watts of sunlight falling
on it; then if we leave it alone - we will have 10 80 watts of solar
heating.

If we build a PV plant; then that same area will give us 20 watts,
and we will have 80 watts of heating - the same as if we didn't build the PV plant.

So the solar proponents are correct.



I previously posted a similar correction: http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=256645&mesg_id=258573
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Tue Sep-28-10 11:18 PM
Response to Reply #95
119. I considered the audience; and over-simplified.
Edited on Tue Sep-28-10 11:20 PM by DrGregory
You used that wrong number several times in the rest of that post.
If you had meant "re-radiates" instead of "REFLECTS", you would have used the right numbers in the rest of your post, and you would have come to the correct conclusion that the solar proponents are right.
Because you had the wrong numbers, you came to the wrong conclusion.
====================================================================

The conclusion is NOT wrong.

Because of the EXTREMELY LOW scientific acumen here; I did simplify
by saying "reflects", when technically a small amount is what a
true scientist would call reflection - the majority is re-radiation.
The mechanism is NOT important. So for the non-scientist, I thought
it would be better if I said "reflection".

However, the conclusion is NOT WRONG - it is CORRECT!!!

The soundness of the conclusion is NOT dependent on the mechanism
by which the energy leaves the ground back to space. All that is
necessary for the conclusion to be correct is that the vast majority
of the energy has to go back to the cosmos.

That is all that is necessary for the conclusion to be COMPLETELY
VALID. It doesn't matter that 10% of the energy returns by reflection
and the rest by Stephan-Boltzmann re-radiation. All that is necessary
for the conclusion to be true is that the vast majority of the energy
returns to the cosmos ABSENT a solar power plant.

However, if you put a solar power plant there; then you change the
amount of energy that returns to the cosmos. The solar power plant
is "blacker" than the undisturbed ground. The solar power plant
absorbs energy that would normally have been returned to the cosmos.

The solar power plant then turns a small fraction of that energy into
electricity; on the order of 20% or so. ( SunPower recently claimed
the highest efficiency title with 24% ). Therefore, 80% of the incident
energy winds up as waste heat.

So 20% of the incident energy is turned into heat and 80% is discharged
as waste heat. For every 20 watts of power; one gets 80 watts of waste
heat power. Equivalently, for every 1 watt-sec of electricity; one gets
4 watts-sec of waste heat.

Now a conventional Rankine cycle electric power plant is 40% efficient.
For every 40 watt-sec of electricity, one gets 60 watt-secs of waste heat.
Equivalently, for every 1 watt-sec of electricity, one gets 1.5 watt-secs
of waste heat.

Therefore, the waste heat production of solar plants EXCEED the equivalent
sized Rankine steam cycle plant. Yet the solar proponents complain about
the waste heat from Rankine cycle plants.

People who live in glass greenhouses, shouldn't throw stones.
HYPOCRITES!!!

Dr. Greg


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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 12:13 AM
Response to Reply #119
124. This is actually REAL SIMPLE

To anyone who doubts the above; here's something
to think about.

Suppose it is a sunny, and very hot day.

You have your choice of what to wear.

Do you dress in a light color?

Or do you dress in a dark color or black?

On this hot day, which one are you going to
be more comfortable in?

Is it not OBVIOUS? You dress in the light color.

The dark colors or black are going to retain more
energy, and you are going to be hotter. What color
are solar cells? They are usually black or dark
blue. If they are going to be efficient; they
need to be a dark color for maximal absorption.

The solar cell is dark in color because we WANT
it to absorb energy, and not send it back to the
cosmos. However, that solar cell will discharge
80% of the energy it absorbs as heat.

Now, your typical desert is light colored; analogous
to you dressing in light colors. You are going to
be cooler.

If you cover your desert with solar cells, you have
make it "blacker". It is analogous to dressing in
dark colors. You are going to feel warmer; and so
is the desert.

Dr. Greg

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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 12:31 AM
Response to Reply #119
125. and just why is that...???
Because of the EXTREMELY LOW scientific acumen here; I did simplify
by saying "reflects", when technically a small amount is what a
true scientist would call reflection - the majority is re-radiation.
==================================================================

Why is the level of scientific acumen around here SO LOW??

You can make fun and make disparaging remarks about the
"Bible thumpers" or "right wing-nuts" or whatever...

However, I've visited forums in which there were
"Bible thumpers", and right-wingers that had a
grasp of the principles of science and physics
that is VASTLY SUPERIOR to what I've seen here.

Isn't there enough intellectual honesty in the
progressive community to admit that nothing is
perfect.

If one points out a limitation imposed by the
laws of physics on some progressive-favored
technology, then the progessives "think"
( term used loosely ), that they have to
denigrate the claim of the limitation.

When they do that - it is so EASY to PROVE
them WRONG!! One posts a good link to a
University web site. ( Progressives do
respect Universities as sources of good
knowledge, don't they? ) When one denigrates
good physics; one only comes off looking like
a FOOL to the intelligent scholar.

Dr. Greg

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Nederland Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-21-10 11:54 PM
Response to Reply #38
72. Whenever Kristopher writes a post like this one you know he just lost an argument.
The fact that you are a total fraud was just demonstrated conclusively - again. That's about 8 or 10 times in less than a month.

You see it a lot. Someone writes a careful response that point by point refutes a Kristopher post, and he responds with a post completely void of content.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-22-10 04:45 AM
Response to Reply #72
73. It was already proven wrong.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Fri Sep-24-10 11:30 PM
Response to Reply #73
74. The only thing proven...
The only thing that has been "proven"
by the muddled logic of the above post
is that kristopher has ZERO knowledge
of the Laws of Thermodynamics - particularly]
the 2nd Law of Thermodynamics.

He doesn't understand "entropy" and why a
engine MUST reject waste heat to carry away
entropy. I have given him the link to a
respected source; the Physics Dept at
Georgia State University:

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html

Quoting the above:

"Second Law of Thermodynamics: It is impossible to extract
an amount of heat QH from a hot reservoir and use it all
to do work W . Some amount of heat QC must be exhausted
to a cold reservoir. This precludes a perfect heat engine."

He has one source he quotes ad naseum, and that source isn't
too impressive when it comes to knowledge of physics.

What can one do when people refuse to learn?

Dr. Greg
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-25-10 04:39 PM
Response to Reply #74
76. The fundamental basis of science is the ability to practice sound reasoning
Edited on Sat Sep-25-10 04:45 PM by kristopher
You lack that ability.

Dr Greg on energy efficiency, original exchange:
In reply to my statement, "For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose", you wrote:
The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg


My reply:
Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.



Also see:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258302

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258337


You have since posted about 10 more posts trying to peddle the same nonsense. Neither solar panels, wind turbines nor electric motors are "engines" converting chemical energy to mechanical energy. Your analysis of the comparative losses of an electric drive vs internal combustion engine are the ravings of someone completely detached from reality that apparently lacks the requisite reasoning ability to even function in daily life, much less do even basic science.

An engine is a machine designed to convert energy into useful mechanical motion. In common usage, an engine burns or otherwise consumes fuel, and is differentiated from an electric machine (i.e., electric motor) that derives power without changing the composition of matter. ...
en.wikipedia.org/wiki/Engine



So... I'll continue to focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sat Sep-25-10 08:17 PM
Response to Reply #76
79. Give them a little rope, and they'll hang themselves...
Edited on Sat Sep-25-10 08:20 PM by DrGregory
Neither solar panels, wind turbines nor electric motors are "engines" converting chemical energy to mechanical energy. Your analysis of the comparative losses of an electric drive vs internal combustion engine are the ravings of someone completely detached from reality that apparently lacks the requisite reasoning ability to even function in daily life, much less do even basic science.
===============================================

More demonstrated ignorance of the Laws of Physics.

These Laws are UNIVERSAL - they don't just pertain
to something that we label an "engine". BTW
solar panels are LESS efficient than Rankine steam
cycles.

With regard to reasoning ability; I'm afraid that
you are the one that is being Aristotelian in
nature.

My reason and logic seem foreign to you because,
unlike you, I AM trained in science and my logic
and reasoning is that of a physicist.

Yours is the "reasoning" of the pretend scientist.

However, the universe doesn't work the way you
"think" (term used loosely) it does.

Contrary to your assertions, even Mother Nature
has to obey the laws of physics. Even Mother
Nature is limited by the Laws of Physics and
the Laws of Thermodynamics.

Just because you don't see how this happens, one
would at least expect that you might take the
opportunity to learn from someone more educated
in the field than you are.

You can't peddle your new age "junk science"
and call it science.

Keep posting for all to see how the laws of
science elude you, and how you can't even
learn when given a link to an authoritative
source such as a University.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-25-10 09:48 PM
Response to Reply #79
82. Sorry, but no.
Dr Greg on energy efficiency

You wrote:
For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg



Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.



Also see:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258302

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258337

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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sat Sep-25-10 02:48 PM
Response to Reply #73
75. Numerous ERRORS

In addition to not knowing the Laws of
Thermodynamics - kristopher also left
out a number of energy losses.

For example, in his calculations, he
ASSUMED 100% conversion of sunlight into
electricity. Solar cells are NOT 100%
efficient:

http://www.renewableenergyworld.com/rea/news/article/2010/06/sunpower-sets-solar-cell-efficiency-record-at-24-2

For large scale PVs SunPower has set a new
efficiency record of 24%.

Of course, the Rankine steam cycle of a
conventional power plant is about 40% efficient.

He also neglected losses in battery chargers, and
those 85% efficient batteries give you 85% efficiency
in charging, and 85% efficiency in discharging ( the
ohmic heating losses are comparable ).

So if one can LEAVE OUT all the data that runs counter
to one's argument; then one can "prove" most anything,
including contentions that are UNTRUE.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-25-10 04:57 PM
Response to Reply #75
78. Are you able to contact reality when you use medications?
Because you certainly were not in contact with reality when you wrote that tripe.
"Dr" Greg wrote
In addition to not knowing the Laws of
Thermodynamics - kristopher also left
out a number of energy losses.

For example, in his calculations, he
ASSUMED 100% conversion of sunlight into
electricity. Solar cells are NOT 100%
efficient:

http://www.renewableenergyworld.com/rea/news/article/20...

For large scale PVs SunPower has set a new
efficiency record of 24%.

Of course, the Rankine steam cycle of a
conventional power plant is about 40% efficient.

He also neglected losses in battery chargers, and
those 85% efficient batteries give you 85% efficiency
in charging, and 85% efficiency in discharging ( the
ohmic heating losses are comparable ).

So if one can LEAVE OUT all the data that runs counter
to one's argument; then one can "prove" most anything,
including contentions that are UNTRUE.

Dr. Greg


1) No claim was made regarding solar panel efficiency. It isn't relevant to the analysis any more than is the original solar input to forming the hydrocarbons in fossilized fuels. You are desperately trying to substitute false claims and false reasoning for sound analysis.

2) The numbers I quoted for battery efficiency include the full charge and discharge cycle. It was clearly written so one can only presume you are, again, out of touch with reality and are not functionally aware of the actual nature of the problem you are trying to analyze.
"State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%." - K
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sat Sep-25-10 08:47 PM
Response to Reply #78
80. The ERRORS keep on coming...Energizer Bunny of ERRORS
1) No claim was made regarding solar panel efficiency. It isn't relevant to the analysis any more than is the original solar input to forming the hydrocarbons in fossilized fuels. You are desperately trying to substitute false claims and false reasoning for sound analysis.

2) The numbers I quoted for battery efficiency include the full charge and discharge cycle.
------------------------------------------------------

I see no where in your analysis where you take into account the
efficiency of the solar panels. If the efficiency of solar panels
are not relevant, as you claim; then why do we have so many scientists
working on attempting to make the efficiency better?

The numbers you quote are those associated with a given charge or
discharge cycle; NOT a combination of both. For that you need
the product of the numbers you quote.

I have yet to see anything REMOTELY resembling "sound analysis"
from you. All we get are parroted bits of junk "pseudo-science"

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-25-10 09:48 PM
Response to Reply #80
81. Nope.
Dr Greg on energy efficiency

You wrote:
For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg



Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.



Also see:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258302

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258337

Printer Friendly | Permalink |  | Top
 
DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sat Sep-25-10 10:15 PM
Response to Reply #81
83. The ERRORS keep on coming...Energizer Bunny of ERRORS
Edited on Sat Sep-25-10 10:17 PM by DrGregory
To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine.
-------------------------------------------------------------------

I don't see what good it does to repost your past ERROR
riddled posts. I've read your unimpressive missives, and
just because you repeat your errors and half-truths doesn't
mean that they are going to get any better with age.

In fact, we in science tend to look down even more on
people who repeat their errors, instead of learning from
them.

In the conversion of chemical energy to mechanical energy,
one could use an external combustion engine in lieu of an
internal combustion engine. Doesn't matter, the SAME
Laws of Physics and the SAME Laws of Thermodynamics apply
to both.

They apply universally. The Laws of Thermodynamics are NOT
just for human built engines. Like all Laws of Physics;
they are UNIVERSAL. Mother Nature obeys those SAME Laws.
The atmosphere obeys the SAME Laws of Thermodynamics that
apply to an internal combustion engine.

You keep trumpeting your ignorance and lack of scholarship
by attempting to imply that somehow "natural" or "renewable"
energy somehow "sidesteps" these physical laws.

That is UNTRUE - Mother Nature obeys these laws.

Quit making excuses for the CRAPPY efficiencies of renewables
by pretending somehow that they are efficient because they
can "sidestep" the laws that human-designed engines must obey.

There's a reason that renewables make up such a piddling
percentage of our energy resources, and it is not due to some
conspiracy by evil capitalist corporations.

When renewables account for a respectable percentage of our
energy resources, then we can discuss whether they are the
wave of the future. Until then, they are only a "work in progress".

Dr. Greg
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-25-10 10:24 PM
Response to Reply #83
84. It shows how substandard are your reasoning skills
Edited on Sat Sep-25-10 10:28 PM by kristopher
It also speaks directly to your complete lack of intellectual integrity.

Dr Greg on energy efficiency

You wrote:
For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg



Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.



Also see:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258302

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258337

Printer Friendly | Permalink |  | Top
 
DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sat Sep-25-10 10:46 PM
Response to Reply #84
85. Improvement????

It also speaks directly to your complete lack of intellectual integrity.
========================================================================

WOW - Kris came up with ONE NEW sentence to add to his previous
ERROR-riddled missives.

Of course, the one sentence is just an ad hominem attack, with
ZERO supporting data, and ZERO scholarship.

Is there any "reasoning" in his attack or error-filled missives?
NO.

Can he cite any physical laws other than the error filled
Aristotelian crap that he makes up on his own?

Besides, my last post basically said that the Laws of Physics
are UNIVERSAL and obeyed by all physical systems; and even
Mother Nature herself obeys these laws in how the atmosphere
operates.

Can there be anything that is more benign yet intellectually
OBVIOUS than the universality of physical law.

Yet, for that claim, I receive the unsupported ad hominem
claim of lack of intellectual integrity.

Surely the hallmark of a SORE LOSER!!!

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-26-10 12:56 AM
Response to Reply #85
86. Nope.
What you are trying to hide...

Dr Greg on energy efficiency

You wrote:
For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg



Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.



Also see:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258302

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258337

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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-26-10 05:30 PM
Response to Reply #86
90. Guess not...
What you are trying to hide...
===================================

I'm not trying to hide anything.

You are the one that is wasting bandwidth and
disk space reposting the same old error-riddled
missive over, and over, and over again.

You can't answer a direct question - you just
repost your error-riddled misunderstandings
of physical law.

You have this misunderstanding that we can
replace the useful work energy that we desire
without paying the price of the waste heat
that the Laws of Physics demand. You seem
to "think" it is our choice to have waste heat.

The Laws of Physics don't let you have the work
unless you pay the price in waste energy.

It's like wanting to take something home from
the store without paying for it. The store
doesn't have to let you walk out with out
paying.

The Laws of Physics don't let you have useful
work - like mechanical energy or electricity -
without paying for it.

Dr. Greg


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glitch Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 01:48 PM
Response to Reply #72
113. He suffers fools more gladly than most of us. IMO he has remarkable patience. nt
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Tue Sep-28-10 11:24 PM
Response to Reply #113
120. You got it backwards..
He suffers fools more gladly than most of us.
------------------------------------------

More like - the fool that needs to be suffered.

Dr. Greg
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 03:58 PM
Response to Reply #35
37. BROTHER!!
The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.
========================================

The entire reason we don't have to have the degree of
waste heat with electricity is SOLELY due to the fact
that the power plant that created the electricity
HAS ALREADY EXPELLED the waste heat for us when
it made the electricity.

You don't know about entropy - heat has it and electricity
and mechanical work do not.

The 2nd Law of Thermodynamics was satisfied as to the discharge
of waste heat when the power plant discharged the waste heat
in cooling the condensers. Ever see a power plant, usually
a nuke; with a big hyperbolic concrete cooling tower with a
plume of water vapor rising from the top?

THAT is where the waste heat for the generation of the electricity
is done. We get the energy in a zero entropy form. We could just
as well run a propeller shaft from the plant turbine to your house;
and deliver the energy as mechanical energy.

The power plant is the real "engine"; it discharged the waste heat
and delivered zero entropy energy in the form of electricity or
mechanical energy. But in order to create that work - electricity
or mechanical - the 2nd Law REQUIRED the expulsion of waste heat.
The power plant did it for you.

When you have a fuel; then you need an engine like the power plant
to turn that into useful energy. Now you "SEE" the engine and the
waste heat that is expelled, as per the 2nd Law.

But just because the power plant expelled the waste heat for you
in creating electricity doesn't mean that waste heat doesn't need
to be expelled when we use electricity. It just means someone
else did it FOR us.

Dr. Greg



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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 04:01 PM
Response to Reply #37
39. ROFLMAO
The fact that you are a total fraud was just demonstrated conclusively - again. That's about 8 or 10 times in less than a month.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 04:09 PM
Response to Reply #39
41. Good that you have laughter in lieu of understanding
The fact that you are a total fraud was just demonstrated conclusively - again. That's about 8 or 10 times in less than a month.
===================================

For Kris; or ANYONE - take my posts above to your
local high school and give them to your local physics
teacher.

The physics teacher will recognize them as CORRECT!!

The fact that good physics is laughed at instead of
learned is sad. No - PATHETIC is probably a better word.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 04:15 PM
Response to Reply #41
43. "Dr." Greg on energy efficiency
You wrote:
For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg



Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 04:53 PM
Response to Reply #43
47. It only shows,..,.
Edited on Sun Sep-19-10 05:05 PM by DrGregory
The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

.....

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.
====================================

The above quantities are not scientifically comparable. It just
shows that kristopher doesn't know the difference between an
"engine" and a "motor".

A course in physics that includes thermodynamics would enlighten
kristopher. A "motor" converts one form of "work" to another form
of "work". Thermodynamically, electricity and mechanical motion
are considered "work". Neither carries entropy - and therefore
the conversion of one to the other can be very efficient.

The gasoline is a "fuel". In a fuel, we have potential energy; in
this case chemical potential energy. We do NOT as yet have "work".
One has to use an "engine" to convert the potential energy in a
fuel into "work".

However, "engines" are limited by the 2nd Law of Thermodynamics.
When the fuel is burned, we have not only energy but entropy.
The engine can not indefinitely "store" entropy - it operates
in a cycle - it has to come back to the same starting point, so
any entropy has to be exhausted. One can't exhaust entropy without
exhausting heat. This is the waste heat that the 2nd Law dictates.

Lest one think that we are "getting away" with something for free;
if the electrical energy or mechanical work is made by an "engine";
and your local electric power plant, be it coal-fired, gas-fired,
nuclear... is an "engine"; in order to make that electricity, the
power plant engine had to exhaust some entropy - and exhaust some
waste heat.

Suppose Bob and Tom are neighbors. Tom cuts his lawn with a mower
with a 3 HP Briggs and Stratton engine. He notes the exhaust going
to the atmosphere. He also notes the heat rising from the engine.
Tom feels that his mower is not environmentally friendly because
it is emitting both heat and exhaust.

His neighbor Bob loans Tom his electric lawn mower. It has a cord
that goes through the fence back to Bob's house. Tom notes none
of the heat and no exhaust when he mows his lawn with Bob's electric
mower. Tom concludes that this way of mowing the lawn is so much
more environmentally friendly than using his 3HP B&S powered mower.

However, remember that cord that runs back to Bob's house through
the fence. That cord ends at a Honda generator that is powered by
the same 3HP Briggs and Stratton engine that Tom has. All the
exhaust gases and all the heat is still being released to the
environment - Tom just doesn't see it, so he ERRONEOUSLY concludes
that the electric mower is environmentally friendlier.

In actuality, the 2nd method is somewhat WORSE for the environment.
They are running the same 3HP engine; but when that engine sits
on the mower deck, it has a direct mechanical connection to the
blade. You can't beat that.

However, with the electric mower, the 3HP engine is connected to
a generator that is NOT 100% efficient. Additionally, the power
cord is not 100% efficient, and there is ohmic heating loss. The
motor on the electric mower is NOT 100% efficient either.

Because of all the losses, generator, cord, motor; the engine on
the Honda generator has to produce MORE energy to accommodate these
losses than it would have if it were directly connected to the
blade while sitting on the mower deck.

So because of Tom's abject IGNORANCE of physics and engineering;
he has come to the WRONG conclusion. Tom "thinks" ( term used
loosely ) that the electric mower is better for the environment,
when it is actually somewhat worse.

"Tom" should NOT be discussing energy and energy policy.

Dr. Greg

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 05:11 PM
Response to Reply #47
49. More "analysis" from the Nuclear Energy Institute?
First electricity and gasoline are both "energy carriers" and are directly comparable in that role.

Second, the grid we are aiming for (which is the point of the entire discussion) is not reliant on centralized THERMAL generation, it is largely composed of systems that harness the the solar energy embodied in light, wind, currents and rain. From those solar inputs we derive electricity with very little heat loss.

And even starting with a grid that is 70% fossil fuels (50% coal 20% natgas), we are introducing substantial carbon savings by means of improved system efficiency.

To put that into perspective:
The California Air Resources Board (CARB) estimates that EVs operating in the Los
Angeles Basin would produce 98 percent fewer hydrocarbons, 89 percent fewer oxides of nitrogen, and 99 percent less carbon monoxide than ICE vehicles.

In a study conducted by the Los Angeles Department of Water and Power, EVs are significantly cleaner over the course of 100,000 miles than ICE cars. The electricity generation process produces less then 100 pounds of pollutants (Reactive organic gases and NOX) for EVs compared to 3000 pounds for ICE vehicles. CO2 emissions are also significantly lower. Over the course of 100,000 miles, CO2 emissions from EVs are projected to be 10 tons versus 35 tons for ICE vehicles.



You do not have the expertise you claim.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 05:26 PM
Response to Reply #49
53. WRONG AGAIN!!
Edited on Sun Sep-19-10 05:26 PM by DrGregory
First electricity and gasoline are both "energy carriers" and are directly comparable in that role.
==================================================

WRONG!!! Electricity is "work" - it is energy WITHOUT entropy.

Gasoline is a "fuel" - fuel has potential energy - but when it is
burned, in addition to energy, you also have entropy. The 2nd Law
tells us that entropy has to be exhausted - and in order to
exhaust that entropy, you have to also exhaust waste heat.

Since the electricity carries no entropy - there is NO such
constraint on using electricity.

Thermodynamics considers both electricity and mechanical motion;
both forms of "work" to be a "higher quality" of energy than that
embodied in a fuel. Heat energy at a higher temperature is
considered "higher quality" than the SAME amount of energy at
a lower temperature. That is because the former has LESS entropy.

The less entropy the better.

You do NOT know your physics; you do NOT know Thermodynamics;
and that leads you to ERRONEOUS statements.

The more you post; the more you prove you do not know this material.

Dr. Greg



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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 05:31 PM
Response to Reply #53
54. This just gets better and better...
WRONG AGAIN!!
Posted by DrGregory


(Kris wrote)First electricity and gasoline are both "energy carriers" and are directly comparable in that role.
==================================================

WRONG!!! Electricity is "work" - it is energy WITHOUT entropy.


An energy carrier is a substance or phenomenon that can be used to produce mechanical work or heat or to operate chemical or physical processes (ISO 13600).
en.wikipedia.org/wiki/Energy_carrier
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 05:42 PM
Response to Reply #54
57. This is Thermodynamics - not lawl
Edited on Sun Sep-19-10 06:01 PM by DrGregory
An energy carrier is a substance or phenomenon that can be used to produce mechanical work or heat or to operate chemical or physical processes (ISO 13600).
en.wikipedia.org/wiki/Energy_carrier
========================================

Who cares what some "standards" agency defines
as energy, or energy carrier, or WHATEVER.

This is PHYSICS - not legalese.

In PHYSICS, electric energy, mechanical energy,
are "work" - they are energy with ZERO entropy.

Heat on the other hand contains entropy.

Higher temperature heat contains less entropy
for the same amount of heat energy as does lower
temperature heat.

Fuels store potential energy; usually of chemical
type. When the fuel is burned; we get heat AND
entropy.

We should be basing our energy discussion on
PHYSICS - not legalese. The reason is that there
is no penalty for violating the Laws of Physics -
the Universe just doesn't allow you to do it.

That can't be said for man-made laws.

Dr. Greg


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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 06:06 PM
Response to Reply #57
62. .
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 06:34 PM
Response to Reply #62
66. Did you read my response?

http://www.democraticunderground.com/discuss/duboard.ph...
======================================================

Did you read my response?

Reading comprehension is pretty bad around here. I said
the Earth would heat up to the temperature of the photosphere
IF there were no re-radiation via the Stephan-Boltzmann law.

Muriel math takes the 4th root to get the temperature. That's
because she was using the Stephan Boltzmann law; which I showed
in the post to which she responded - that the re-radiation goes
as the 4th power of the temperature.

I said "IF NOT FOR" for the Stephan Boltzmann law - and what does
she do - she uses the Stephan - Boltzmann law.

The point is that the re-radiation of energy by the Earth due
to the Stephan-Boltzmann law is a major factor in the Earth's
heat balance. In fact, if it were not important, then global
warming wouldn't be important. It's the re-radiation as per
the Stephan-Boltzmann law that the CO2 traps.

In order for the Earth to be in heat balance, the outflow of
heat energy has to balance the inflow. There is an inflow
of solar radiation, and only a SMALL percentage is directly
reflected. There is an additional influx of heat energy due
to the natural radioactivity in the Earth.

There has to be a substantial outflow of energy in order to
balance the equation. That direct reflection or albedo doesn't
cut it.

What does keep the Earth in heat balance is the Stephan Boltzmann
re-radiation of energy.

Dr. Greg

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bananas Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-26-10 05:34 AM
Response to Reply #66
88. Your response is grossly insufficient (to be polite).
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-26-10 06:05 PM
Response to Reply #88
91. Only to those...
Your answers are grossly insufficient (to be polite).
=============================================

Only to those that are not learned in science.

I stated, correctly, that a portion of sunlight
is reflected. However, the majority of the energy
is re-radiated as per the Stephan-Boltzmann law.

That re-radiation is a major component of the Earth's
heat balance. I considered a hypothetical case in
which "magically" the Stephan-Boltzmann re-radiation
were turned off.

So we had an influx of sunlight, with about 10% reflected.
That left 90% of the influx "unbalanced". There was no
sink or loss term to counter-balance 90% of the influx
in the Earth's heat balance equation.

So what would happen IF the Stephan-Boltzmann radiation
were turned off. The Earth would heat up. After all,
if one understands the Greenhouse Effect - the CO2
in the atmosphere is blocking some of this re-radiation.

What if something wasn't just blocking part of the
re-radiation, but the whole thing, that is all the
re-radiation were turned off. We would have an
EXTREMELY bad Greenhouse Effect - a "runaway"
Greenhouse Effect.

When would that runaway terminate? It would terminate
when the Earth reached the temperature of the energy
source driving the heat up. That is you can't get
energy from something that is colder than you are.
So that would be the photosphere of the Sun.

Of course, one can't turn off the Stephan-Boltzmann
re-radiation; so the extreme temperatures don't
happen in actuality.

Dr. Greg
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 06:23 PM
Response to Reply #35
65. WRONG AGAIN!!
State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.
======================================================

Ever hear of FRICTION!!! Even if you have a motor
that is connected directly to the wheels; you may
not have 100% or ALL of the mechanical output going
to the wheels.

Suppose the axle that links the motor to the wheels
goes through a bearing. There's friction is that
bearing. When the motor turns the wheels; that
bearing will heat up. The heat energy that heats
up the bearing is energy sapped from the output
of motor - it doesn't go to the wheels.

If we listened to you, I guess we'd all forgo
greasing our axle bearings.

Dr. Greg

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madokie Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 07:33 PM
Response to Reply #65
118. Are you sure you haven't forgotten to grease your axle bearings a few times already?
:rofl:
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Tue Sep-28-10 11:30 PM
Response to Reply #118
121. Even with grease....
Are you sure you haven't forgotten to grease your axle bearings a few times already?
=================================

You have friction even WITH GREASE.

Do you know of a grease that drives the friction to
a hard zero? Have you ever picked up a grease covered
piece of metal? The only reason you can pick it up
is because you have friction to transfer the force
from you fingers. If the grease were PERFECT; you
couldn't pick it up.

There is NO perfect grease; so even with grease there
is friction.


Dr. Greg

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txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 04:23 PM
Response to Original message
44. I can't believe you have pushed me so far as to DEFEND kristopher
Dr. Greg and NNadir, you should agree with kristopher that we need to get OFF of all fossil fuels. Further, that our future does not and should not hinge on continued use of heat engine technology.

Kristopher, you should agree with Dr. Greg and NNadir that spending all your time bad mouthing nuclear power while barely mentioning the enormous problems caused by existing coal power plants (let alone any future ones) does not help your case, does not establish a unified front among the various zero-carbon alternative energy proponents.

Can we all agree that we all should be finding the common ground that we all share, not bickering amongst ourselves over semantics and arcane scientific minutiae.

Fossil fuels are the cause of many problems such as exacerbating the trade deficit, loss of American jobs, air pollution, health problems, the budget (national and your family's), and last but not least, national security.

Let's agree to disagree on some of the other things and put that behind us. But can we please begin to work together to fight the common threat that fossil fuels actually pose to us today and the danger of its continued use to our future and our childrens' futures.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 04:40 PM
Response to Reply #44
46. Thank you but...
I see a focus on fossil fuels as being unnecessary at DU - it is preaching to the choir. This is a progressive space and the progressive position accepts the problem of AGW and seeks a solution for it.

The fact is that our fastest route to a solution to carbon lies with either a largely nuclear solution or a largely renwable solution. For reasons of economics the two are actually mutually exclusive in that pursuing both strategies strongly impacts how effectively and quickly we make a transition.

This statement by Citigroup shows the nature of the problem. They are speaking of the mixed approach you are suggesting. Note that if renewables are installed at the pace and quantity planned, there is not enough of a market for the nuclear plants to survive. The result will be to declare bankruptcy, wipe out the debt and sell the electricity for their operations and maintenance costs. That, in turn discourages new investment in nuclear power on the one hand and concurrently reduces investments in renewable manufacturing because of artificially low prices for the nuclear energy.
A second order problem flowing from this dynamic is that it will absolutely lead to efforts on the part of nuclear power plant owners to sell enough electricity to pay for the nuclear plant or (after bankruptcy) to increase profits. That is part of the perverse incentive problem with the present system - it is geared to encourage consumption.

I have no problem with a healthy discussion on nuclear power, but that isn't what is happening here.


Citigroup 2008 impact of renewables and energy efficiency
What the market should not take for granted

GDP impact on demand and load factors

Consensus view is that electricity demand in the wide European region will grow by 1.5% p.a. over the next couple of decades. This is a view shared by UCTE in its latest System Adequacy Report. Although it is virtually impossible to produce irrefutable electricity demand forecast we are tempted to argue that the risks are on the downside since:

1. During the boom years of 2003-07, when GDP growth was strong and infrastructure investment high on the back of very liquid debt markets and due to the convergence of the new EU joiners, electricity consumption grew by 2.1% p.a.

2. Energy efficiency is likely to become a bigger driver as technology advances and as awareness rises. It is important to highlight that such measures also fall under the Climate Change agenda of governments, which has been one of the driving forces behind the renaissance of new nuclear.

As a result, we would expect electricity demand growth to be in the 0-1% range for at least the next 5 years, before returning to more normal pace of 1.5-2%. We therefore see scope for an extra 346TWh of electricity that needs to be covered by 2020 vs. 2008 levels.

Should EU countries go half way towards meeting their renewables target of 20% by 2020 that would be an extra ca. 440TWh. Even if EU went only half way, which by all means is a very conservative estimate, that would still be ca.220TWh of additional generation. Under its conservative scenario A forecast, UCTE expects 28GW of net new fossil fuel capacity to be constructed by 2020. On an average load factor of 45% for those plants thats an extra 110TWh.

Therefore under very conservative assumptions on renewables, we can reliably expect an extra 330TWh of electricity to be generated by 2020, leaving a shortfall of 16TWh to be made up by either energy efficiency or new nuclear.

There are currently 10GW of nuclear capacity under construction/development, including the UK proposed plants that should be on operation by 2020. If we assume that energy efficiency will not contribute, that would imply a load factor for the plants of 18%. Looking at the entire available nuclear fleet that would imply a load factor of just 76%. We do believe though that steps towards energy efficiency will also be taken, thus the impact on load factors could be larger.

Under a scenario of the renewables target being fully delivered then the load factor for nuclear would fall to 56%.

(Bold in original)

Citigroup Global Markets European Nuclear Generation 2 December 2008




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4dsc Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 05:41 PM
Response to Reply #46
56. I see you still don't see the oil problem here
thanks for confirming my earlier statement that you are attempting to confuse oil which is a transportation fuel with power generation sources.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 05:47 PM
Response to Reply #56
58. In EVs electricity is a transportation fuel.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 05:58 PM
Response to Reply #58
60. Don't know the difference
In EVs electricity is a transportation fuel.
==============================

You show again that you do NOT know the
difference between "work" and a "fuel"

Electricity is NOT a fuel. Physics makes
a distinction between work and fuel.

For everyday use; such sloppy terminology
has no downside. However, when people are
discussing energy, and energy policy; such
sloppy and inaccurate terminology leads
to ERRORS.

Dr. Greg

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4dsc Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-20-10 07:14 AM
Response to Reply #60
70. Its obvious kris doesn't understand the difference.
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txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 07:37 PM
Response to Reply #46
69. Who framed the debate as an either or proposition?
I've seen this time and time again on DU and it really sickens me. Population growth is happening in the United States, from immigration if nothing else. Per capita electricity use is not going down. We must conclude, therefore, that by 2050 we will need a many more power generating plants than we currently have now. Those plants can either be natural gas or coal burner technology, nuclear power, concentrated solar thermal, geothermal, solar PV, wind power, tidal power, wave powered, or a combination of some or all of those. Those are the facts. We are going to need additional power plants.

With an atmosphere of solar folks fighting it out with nuclear folks we will end up with predominantly coal and natural gas power plants and maybe some renewable energy thrown in there.

If we all banded together, supported each other, we might (just might) end up with mostly renewables and continually decreasing amounts of coal and natural gas power plants.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 05:13 PM
Response to Reply #44
50. The problem is that he is WRONG!!
Can we all agree that we all should be finding the common ground that we all share, not bickering amongst ourselves over semantics and arcane scientific minutiae.
==================================

The problem is that kristopher is just plain WRONG!!!

He doesn't know the science. He doesn't know the difference
between "engines" and "motors". He doesn't know the difference
between a fuel and electricity - he "thinks" they are just "carriers".

You can't agree to disagree when someone is scientifically WRONG!!!

Just like "Tom" in my example, the abject ignorance of the science
leads Tom to make an ERRONEOUS conclusion. Should we just agree to
disagree and consider Tom's opinion as valid as anyone else's?

NO!!! When someone is WRONG they need to be told that they are
WRONG. People need to see that they are WRONG!! That way we
get people good information on which to base their opinions.

We should NOT have people basing their opinions on bad "junk science"
from someone who doesn't know his science; just because we have
agreed to disagree.

Dr. Greg
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 05:17 PM
Response to Reply #50
51. Demonstrate how the efficiency numbers I posted are "WRONG!"
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 05:35 PM
Response to Reply #51
55. Apples and Oranges
Demonstrate how the efficiency numbers I posted are "WRONG!"
==================================

It is WRONG because the efficiencies are NOT
on the same scale.

With a motor - you can do everything to attempt
to approach 100% efficiency. With a motor,
100% efficiency is the goal.

With an engine; you can NEVER attain 100%
efficiency. The BEST you can do with an
engine is something called the "Carnot Efficiency".

If the Carnot efficiency was 50%, and you have
an engine that is running at 50% - then that is
the BEST you can do.

You can't say - "that engine is inferior because
it is only 50% efficient, and my electric motor
is 99% efficient'.

For what it is doing - it is doing the BEST that
physics allows.

As for your 99% efficient motor; it is running
on electricity generated by a 25% efficient engine.

So if you look at the whole system - the Carnot
engine is better.

Again, you are making the same mistake that "Tom"
in my example is - you are not looking at the whole
cycle.

You look at a "motor" with 95% efficiency, and say
it's better - when it is NOT if the engine that is
providing the electricity is LESS efficient.

Dr. Greg
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 06:06 PM
Response to Reply #55
63. .
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 06:46 PM
Response to Reply #63
68. Why not debate the substance?

Why post links to what OTHERS have posted;
even when they were shown to be WRONG too.

If you have an exception - let's hear it;
and let's debate the PHYSICS - not the
politics, or what some standard which has
been dumbed down so perfunctories can
execute them.

Let's debate the physics!!

Dr. Greg

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diane in sf Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 03:03 AM
Response to Reply #55
92. this is nonsense
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Tue Sep-28-10 11:38 PM
Response to Reply #92
122. Someone else that didn't take high school physics...
Edited on Tue Sep-28-10 11:39 PM by DrGregory
WRONG Dianne - 100% WRONG!!!

There is a difference between an engine
and a motor. A motor changes one form
of energy, electricity, into another
form of energy, mechanical motion.

However, neither electricity nor mechanical
motion carries "entropy". Therefore, the motor
is unconstrained by the 2nd Law of Thermodynamics.

An engine burns a fuel, and because the energy
is heat; there is also entropy. Because of the
2nd Law of Thermodynamics; one can NOT turn that
heat energy ALL into useful work.

If you don't believe me; believe the Physics Dept
at Georgia State University:

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html

QUOTING:

"Second Law of Thermodynamics: It is impossible to extract
an amount of heat QH from a hot reservoir and use it all to
do work W . Some amount of heat QC must be exhausted to a
cold reservoir. This precludes a perfect heat engine."

UNQUOTE.

This is taught in high school physics; so I must assume
that you never took high school physics.

What you are calling "nonsense" is instead "GOOD SCIENCE"
as here verified by the Physics Dept. of a University.

WRONG WRONG WRONG, Dianne.

Dr. Greg
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-29-10 12:09 AM
Response to Reply #122
123. No, you are worming away from your original screw up and it is obvious
Your original post where you quote me and respond is provided, as is my response:


Dr Greg on energy efficiency

For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg



Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.



Also see:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258302

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258337

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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 01:04 AM
Response to Reply #123
126. ERROR ERROR ERROR!!!!
No, you are worming away from your original screw up and it is obvious Updated at 3:27 PM

Your original post where you quote me and respond is provided, as is my response:
============================================

For the umpteenth time you post the same
ERROR-RIDDLED tripe.

Your manifest ignorance of the laws of physics
show in that piece.

Waste heat is NOT something that has "no purpose"
and we can take or leave. Waste heat HAS a purpose.

I don't know why you can't understand this - high
schoolers can understand it.

The purpose of waste heat is to carry away the entropy.

Repeat that 1000X or whatever number it takes to get
the concept into your head.

Look at the link to the Georgia State University
Physics Department that I quote above.

They say you can NOT have all the energy QH be
converted to work W.

They say you HAVE to reject an amount QC to
the cold reservoir. That energy QC is the
"waste heat".

The 2nd Law of Thermodynamics says you HAVE to
have it. You just don't know where to look for it.
You "think" ( term used loosely ) that we can
get that useful work without the waste heat.

The 2nd Law of Thermodynamics says you are 100% WRONG!!!

You can post your ERROR-RIDDLED tripe repeatedly until
the cows come home and it doesn't make it right.

I showed you response to my fellow scientists at the
Lab at lunch time, and they can hardly believe that
there is someone that believes what you do.

As I stated before; take my posts to your local high
school physics teacher and verify that they are correct.

Dr. Greg
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 07:19 AM
Response to Reply #123
127. Perhaps it would be instructive...
Edited on Wed Sep-29-10 07:26 AM by DrGregory
Perhaps it would be instructive if I told you
one of the mechanisms by which wind turbines
generate waste heat.

Because of your manifest ignorance of science and
the laws of physics, I bet you didn't even know
that wind turbines generated waste heat. You
"thought" ( term used loosely ) that wind turbines
just turned wind energy into electricity and didn't
have the inefficiencies that plague conventional
sources.

The blades of a wind turbine are airfoils - they are
like the wings of a plane. The reason the wind turbine
turns is that the effective air pressure on one side of
the blade is greater than the other side of the blade,
and the difference in pressure serves to turn the blade.

The same thing happens with an airplane, the pressure
below the wing is greater than the pressure above the
wing, and the difference in pressure results in a net
force upwards that holds the plane in the air against
the downward force of gravity.

There HAS to be this pressure difference or the plane
won't fly or the wind turbine won't turn. If the pressures
were equal, neither would work.

However, look at the tip of either wing or blade. There
is higher pressure on one side, lower pressure on the
other. In addition to generating the force, the air
"wants" to attempt to equalize that differential by
doing an "end run" around the tip of the wing or blade.

This generates a vortex at the tip of the wing or blade.
The air swirls in a horizontal "tornado". You can see
the effect of the vortex from each wing in the following
pictures. Look at the pictures of the airliner that
are after the ones with the Statue of Liberty and the
Space Shuttle launch. To see the effect of the two
counter-rotating vortices, look at the clouds BEHIND the planes:

http://sites.google.com/site/thewarehousekc/flying-machines

The vortex takes energy, and is part of the "form drag" of
the wing. A wing can't generate lift without generating drag.
Conservation of energy doesn't let you get anything for free.

The same vortex structures are shed from the tips of the
blades of a wind turbine. Just like with the airliners,
the vortex interacts with the surrounding air and is
dissipated. The energy associated with the vortex winds up
as HEAT!!

Yes - even wind turbines generate waste heat. It's one of the
reasons the efficiency of a wind turbine is so monumentally
CRAPPY.

The steam turbines in conventional electric power plants are
VASTLY MORE EFFICIENT than wind turbines. They are designed
to be. The steam flows through a nozzle before even the first
blade of the steam turbine in order to optimize flow direction
and velocity. The steam turbine can have stator blades between
each set of rotating blades that look like turbine blades but
help redirect and optimize the flow of steam to the next set of blades.

The steam turbine has multiple sets of blades in serial fashion.
The steam turbine may be a tandem compound; multiple turbines
linked together with reheat of the steam between stages.

Steam turbines are VASTLY MORE SOPHISTICATED than the single,
open air airfoil that is a wind turbine. However, with ALL
that going for it; the steam turbine can't escape the laws
of thermodynamics; and neither can a wind turbine.

Wind turbines waste energy just like other sources. You just
didn't know about it because of your lack of knowledge of the
relevant physics.

Why not LEARN about the technology so you can give an
accurate portrayal, instead of this pollyannaish drivel.

Dr. Greg

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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 08:45 AM
Response to Reply #127
128. So in the end; wind turbines also affect the environment
Edited on Wed Sep-29-10 08:46 AM by DrGregory
Son in the end, wind turbines also affect the
environment.

The kinetic energy of the atmosphere eventually
winds up as heat. However, by the installation
of wind turbines, we hasten that process along.

In the process of extracting useful work, our
monumentally inefficient wind turbines also
turn kinetic energy of the air into turbulent
kinetic energy and heat; prematurely.

That kinetic energy should have been available
for moving the weather system. The weather system
should have been able to mover farther before it
ran out of its motive energy. Instead, we
turn it into higher entropy turbulent kinetic
energy and heat. What a waste.

However, that's the price we have to pay for
the energy we desire. We affect the atmosphere
just as other energy sources do.

We don't get to pick IF we affect the environment.

We don't get useful work without waste heat.

Quit pretending that the so-called renewables
are virtuous and all other forms of energy
generation are to be denigrated. It isn't true;
and the thesis that renewables are so virtuous
is just a manifestation of IGNORANCE.

Dr. Greg
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txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Fri Oct-01-10 10:20 AM
Response to Reply #128
135. Efficiency only matters when you are paying for the fuel
Edited on Fri Oct-01-10 10:23 AM by txlibdem
Dr. Greg/Kristopher, please kiss and make up. Together you could be an effective motivator to GET US OFF OF FOSSIL FUELS. But your continued bickering and personal animosity is getting in the way of moving forward. This serves the rich, the corporations, the forces of status quo, and the coal and oil industries. I don't understand why you two cannot come together against the TRUE enemies of our collective future, fossil fuels and corporate domination of politics and policy. Together we stand, divided we fall.

Now to my comment. I've heard so many people incorrectly lambasting the efficiency of solar and wind power. Why do I care about the efficiency when the "fuel" is free and is continuously replenished moment by moment. Efficiency comes into play when the fuel costs you money, or when you have to expend energy/do something to keep the fuel coming (such as a gas grill - it's cheap to run but you have to take the tank to have it filled or traded for another one at regular intervals). But when the fuel costs you nothing and there is nothing that you have to do in order to keep the sun shining or the wind blowing the argument of efficiency is moot and IMO misleading.

What IS important in wind turbines is how many kilowatt hours it will generate over the day (or week/month/year) as compared to the cost of purchasing and installing it. Add in the maintenance costs if the turbine has gears, fluids, and an active system to point the blades into the wind as well. These parts will wear out, require monitoring, or use energy/waste energy.

What IS important in solar panels is how many kilowatt hours it will generate each day, averaged over a day/month/year/season versus the cost of purchasing and having it installed.

There are serious problems with currently available small wind turbines for residential applications. They cost too much, do not start turning till the wind hits 8 to 10 mph (which means you will generate ZERO energy for 70% of the year). The manufacturers quote the rated power output in winds of 28 mph!!! In most parts of the country that means that 90% to 95% of the time you WILL NOT get anywhere near the rated output. This is wrong IMO. They should have a more realistic output rating and you shouldn't have to spend an hour to learn that the product will be nothing but a yard decoration unless a storm is coming through.

There are serious problems with utility scale wind turbines. New technology, however, is coming online now that will solve some of the problems. GE and Siemens are both coming out with wind turbines that have no gears and will therefore require far less maintenance, will be far more reliable. This is great news for the wind industry.

So, let's be realistic about the limitations and true output of our alternative energy projects but let's not get bogged down in technical aspects that, in the end, do not make a lot of difference when we're talking about wind or solar power.

And the comment about wind turbines heating up the atmosphere? Wow. I'm not even going to dignify that with a response.
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sat Oct-02-10 04:21 PM
Response to Reply #135
136. No response was required...
Edited on Sat Oct-02-10 04:25 PM by DrGregory
So, let's be realistic about the limitations and true output of our alternative energy projects but let's not get bogged down in technical aspects that, in the end, do not make a lot of difference when we're talking about wind or solar power.

And the comment about wind turbines heating up the atmosphere? Wow. I'm not even going to dignify that with a response.
====================================================================================

It doesn't require a response. It just happens to be TRUE.
Is it a problem? NO! But it does serve as a counter-example
to the ERRONEOUS portrayal of the physics of energy that we
have been getting from one poster.

We've been getting the pollyannaish crap that "waste heat"
has no purpose or is unnecessary when it is just not true.
Unfortunately, the laws of physics and science are not "kind"
to us when we want to produce energy. The forces of Nature
impose hard and fast LIMITS as to what we can / can not do
when we produce useful energy.

Some of these laws REQUIRE that we exhaust waste heat in order
to obtain useful work. Pretending that all we have to do is
produce the useful work and not expend waste heat, which is just
a ploy of evil power companies to get us to pay more for something
that we don't even get to use; is NOT HELPFUL.

We have Aristotelian "thinkers" that fabricate physical laws instead
of learning true science.

Evidently you missed the point on the example of waste heat and
wind turbines. There's no "problem" with this - it was used as
an example to show that even the technologies that some consider
holy and sacred, still have to obey the laws of physics.

If efficiency isn't important, then you should tell all the scientists
that are working on improving the efficiency that they are wasting their
time on something unimportant. Of course efficiency is important.

The better the efficiency, the more final product in terms of useful
energy you are going to get for a given cost of material, land....
The input solar energy may be free, but the land, material and other
costs associated with solar are NOT free. You do pay for land, material....
so efficiency IS important, even if the solar energy, the "fuel" is free.

Environmentalism has a bigger enemy than the rich corporations.
Environmentalism has a CANCER from within - that cancer is IGNORANCE.
Ignorant environmentalists are a bigger threat to the environmental movement
than rich corporations. Ignorant environmentalists will sell their
ill-conceived visions for energy policy. The problem is that their visions
are inconsistent with the laws of physics, and the laws of physics will
prevent them from working. Then where will a DISGRACED environmental movement
be?

I agree with Dr. Patrick Moore who said in a seminar to the World Affairs
Council of Western Michigan, that if we miss the opportunity to prevent the
effects of global warming, the fault will lie with the environmentalists who
myopically focused on the wrong technology; solar power. See:

http://www.c-spanvideo.org/program/199958-1

As long as people make ignorant, ill-consider, and FALSE statements
about the technical aspects of obtaining useful energy; then I will
continue to point out their ERRORS.

If you have cancer, who do you want advising you? Do you want some
"quack" who is unlearned in medicine telling you to think good thoughts,
and eat only organic foods and you will be fine? That could get a
cancer patient seriously dead.

Or do you want a medical doctor, a scientist; who is going to tell you
some things you may not like to hear - that you need chemotherapy and
radiation treatments. However, the medical doctor is the one that has
the best chance of curing you.

Likewise, the public does NOT need pollyanaish CRAP based on someone's
fabricated knowledge of how the Universe works. That will only lead
to disappointment in the end.

The public needs good sound science to base energy policy on.

In that regard, I'd like to recommend a book by a UC-Berkeley physics
professor, Dr. Richard Muller called "Physics for Future Presidents".
People need to learn some REAL science, and NOT the made up garbage
proffered by some.

Dr. Greg


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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-29-10 08:53 AM
Response to Reply #127
129. "Dr." Greg on energy efficiency
Your original post where you quote me and respond is provided, as is my response:


Dr Greg on energy efficiency

For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?
=========================================

The above is a disingenuous half-truth. While it is true that the engine of a
automobile is about 20% efficient and 80% of the energy goes as waste heat.

However, what he is NOT saying is that the 2nd Law of Thermodynamics states
that you HAVE to have waste heat in order to get the 20% useful work.

He is attempting to imply that we could somehow get that 20% desired useful
energy without the 80% waste heat.

This shows IGNORANCE of the 2nd Law of Thermodynamics. We MUST according to
the 2nd Law of Thermodynamics have that waste heat because that is what carries
away the entropy.

The mechanical work energy of the engine doesn't carry away any entropy - so
you would have a source of entropy and no sink for the entropy. Such an engine
could not continue running in a cycle.

So that 80% waste heat DOES HAVE a purpose - it carries away the entropy and
it ALLOWS us to get that 20% useful work.

Without the 80% "waste heat" - you can NOT GET the 20% useful mechanical work.

This is high school level physics - get a high school physics text and turn to
the section of the Laws of Thermodynamics.

Dr. Greg




Leaving aside the other peculiarities of your statement, I'll focus on the main point - why we DON'T have to replace the wasted energy from an internal combustion engine when we consider how to power our personal transportation fleet.

The short version is that you only have that degree of waste heat in this application when your energy carrier is petroleum, not when the energy carrier is electricity.

To assist those not familiar with the topic (like "Dr." Greg):

Petroleum is an energy carrier that requires a chemical reaction to release the solar energy stored in the hydrocarbon bond. To harness that stored energy requires harnessing the heat released on combustion and converting it to mechanical energy via an internal combustion engine. So we have solar energy stored by living organisms that has been sequestered away for eons, then extracted, transported, refined, transported some more and then used in a contained explosion. Further, that mechanical energy must be transferred from the point of the reaction (cylinder) to the point of work (turning the wheel). All of those transactions are a debit against the original solar energy stored in the hydrocarbons.

The fuel 'tank to wheel efficiency' of most autos is actually between 12-20% with most vehicles coming in around 15%.

Alternatively, we can harvest the solar directly with PV or solar thermal, or we can harvest it indirectly by capturing the mechanical force of the wind or water currents (both motions are a product of solar input).

The output of all of those technologies is electricity. This electricity might be distributed for immediate use or it might be stored in various types of batteries (ie thermal, chemical or gravity).

Petroleum has been difficult to replace because of its high energy density. However, as noted above, because of waste from the process of harnessing the stored energy of petroleum, that degree of energy density isn't what needs to be replaced. All that we need to replace is the amount that turns the wheel and propels the auto down the road.

State of the art electric motors turn about 95% of their input electrical energy into mechanical energy. Since the shaft of the electric motor directly turns the wheel of the auto all of the mechanical output goes to pushing the car.

State of the art lithium batteries used in the electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) that all manufacturers are now turning to can store and deliver the input electric energy with efficiencies greater than 85%, almost always higher than 90% and often as high as 99%.

We derive the 'tank to wheel efficiency' for an electric vehicle by putting those numbers together:

From a low of 100%(input) X 85% (battery) X 95% (motor) = 80.75% efficiency

to a high of

1oo% of input stored in a 99% efficient battery through a 95% efficient motor = 94.05% efficiency for a loss to heat of between 6-20% depending on the technology versus a loss of 80-88% for internal combustion technology.

Battery technology is rapidly developing and technologies in the production design phase are capable of storing sufficient energy in battery packs of the weight used today to give an auto the weight of today's Volt or Leaf a range of about 800 miles.

When you hear all the talk about "energy efficiency" being a large part of the solution to our energy problems, this is the type of solution that is under discussion.

So we can waste between 80-88% of the energy in a gallon of gasoline used for our personal transportation or we can waste between 6-20% of each kilowatt of electricity we use.

88% waste or 6% waste.

"Dr." Greg, all of that is consistent with the laws of physics.



Also see:
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258302

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=115&topic_id=256645#258337
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 12:33 PM
Response to Reply #129
134. Tripe, tripe, and more tripe...
Your original post where you quote me and respond is provided, as is my response:
============================================================

For the umpteenth time, you've posted your same
ERROR-RIDDLED response.

Just because you waste bandwidth and storage space
posting something over and over and over again is
NOT going to make that ERROR-RIDDLE tripe into
a correct answer.

You are never going to turn that "sow's ear" of a
response into a silk purse; no matter how many
times you post it.

It's CRAP now and will forever remain CRAP.

( That must also be a fundamental law of physics )

Dr. Greg
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4dsc Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 05:51 PM
Response to Original message
59. Just for you kris
Renewable energies - the fake fire brigade

So while some havent really recognized that we will soon run into serious problems from traditional fossil fuels, others are already preparing a brighter future, which will bring independence from coal, oil and gas, with far lower carbon dioxide emissions to boot. In many European countries, thanks to subsidies and purchasing guarantees, large amounts of renewable electricity generation capacity has been built during the last decade, and in the U.S., corn based ethanol now has a government-mandated share of up to 10% in fuel gasoline. But let us not fool ourselves: during those 10 years, despite all the relative successes, renewable energies (including hydropower) grew by far less compared to the global increase in total energy consumption. Overall, our global energy delivery system continues to be as dependent on fossil fuels as ever before, or even more so. On top of that, even those renewable technologies are mostly based on fossil fuel inputs, which are either used during the manufacturing of the equipment, or even during production and processing (e.g. biofuels).

http://www.theoildrum.com/node/6641

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Sep-19-10 06:03 PM
Response to Reply #59
61. Do you understand exponential growth?


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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Sep-19-10 06:17 PM
Response to Reply #61
64. Do you understand...
Do you understand exponential growth?
=========================================

Do you understand the conditions under
which you get exponential growth?

Do you know what the form of the
differential equations the system obeys
is necessary so that the solution is
an exponential?

Tell us what form the differential
equation takes; and why that particular
form of differential equation is a good
model for whatever you are blabbering
about at the moment...

Dr. Greg

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4dsc Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-20-10 07:16 AM
Response to Reply #61
71. Do you understand this?


Everything you mentioned is dependent upon oil.
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Terry in Austin Donating Member (1000+ posts) Send PM | Profile | Ignore Sat Sep-25-10 04:55 PM
Response to Original message
77. No bull: Denial, Anger, Bargaining, Depression, Acceptance
Looks like we're stuck somewhere between stage 2 and stage 3 here, i.e., "Damn you if you don't believe we can run business as usual when the fossil fuel peters out" and "Hey, maybe if we just build some real keen technology, then Nature will let us keep our business as usual."

It's a big loss, this party being over -- the industrial age was tons o' fun, and there's a lot to miss about it. But it seems to me that sooner or later, it's time to cowboy up and face facts: all the fine gadgets and all the fine math in the world aren't going to keep our 100+ energy slaves with us. Better just to get on with it and arrange things so we can be comfortable with 5 or 10. That's something we actually can do.

YMMV. You may now shoot the messenger.

:hide:

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 05:40 AM
Response to Original message
93. Sample
Edited on Mon Sep-27-10 05:41 AM by kristopher
Matching Utility Loads with Solar and Wind Power in North Carolina


Open Access Document
Executive Summary

Matching Utility Loads with Solar and Wind Power in North Carolina
Dealing with Intermittent Electricity Sources

by John Blackburn, Ph.D.
March 2010

Those reluctant to endorse a widespread conversion to renewable energy sources in the U.S. frequently argue that the undeniably intermittent nature of solar and wind power make it difficult, if not impossible, to provide reliable power to meet variations in demand without substantial backup generation. Several studies, concentrating on areas with ample sources of both wind and solar power have suggested that a combination of the two, when spread over a sufficiently wide geographic area, could be used to overcome the inherent intermittency of each separately, reducing the need for backup generation. Moreover, since the backup power is required at more or less randomly distributed times, the availability of baseload power, so strongly entrenched in utility circles, becomes more or less irrelevant.

This study examines these ideas with data gathered in the state of North Carolina. Contrary to the idea that such an arrangement will be subject to heavy backup requirements from conventional sources, the clear conclusion of the study is that backup generation requirements are modest and not even necessarily in the form of baseload generation.


In North Carolina the two largest potential renewable electricity sources are solar and wind generation. The former is the case almost everywhere in the U. S., the latter is also the case in North Carolina, given wind resources in the mountains, along the coast, and offshore, both in the Sounds and in the ocean. Hydroelectricity (now 2,000 megawatts (MW) and potentially 2,500 MW) and biomass combustion represent the other renewable sources available in the State. Solar and wind generation have some obvious complementarities. Wind speeds are usually higher at night than in the daytime, and are higher in winter than in summer. Solar generation, on the other hand, takes place only in the daytime and is only half as strong in winter as in summertime.

The study described here used hourly North Carolina wind and solar data for the 123 days of the sample seasonal months of January, July, October, and April. This entailed making 2,952 observations at each of three wind sites and three solar sites or 17,712 entries in all. In the absence of actual kilowatt-hour output data for long periods from functioning installations in widely separated locations, wind speed and solar irradiation were taken at the three sites each and converted to presumed wind and solar power outputs. Wind data was converted using the specifications of the wind turbines chosen for the study, shown below. Actual power readings for shorter periods from solar installations at two sites (from readings made in different years), were used to calibrate the presumed solar output at the chosen sites.

The generation patterns given by these sites were, for this initial exploration, taken to be representative of all of the sites in North Carolina. Solar and wind power generation constructed as outlined above were then scaled up to represent 80% (40% each) of average utility loads for the four sample months, with the remainder coming from the hydroelectric system (8%) and assumed biomass cogeneration (12%). The annual utility load was taken to be 90 billion kWh, a somewhat more energy-efficient version of the present 125 billion kWh load. Average hourly loads in each of the four seasons were taken from Duke Energys 2006 load profile. These were modified to show some reduction in summer and winter peaks as structures become more energy-efficient and enjoy disproportionate reductions in heating and especially cooling energy demands. The reductions were based on the authors data set of measured energy use in more than one hundred North Carolina homes.

Wind generation was calculated from wind speeds using the cut-in, cut-out speeds and power curve for the General Electric 1.5 MW turbine (model 1.5xle). Solar generation was taken to be proportional to solar radiation at a ground level flat surface. Not surprisingly, wind generation from the three wind sites combined showed less variability than at each site separately. Solar generation did likewise, but with less variation to begin with. The literature suggests that day-by-day and hour-by hour wind variation would be further reduced by adding many more sites far enough apart to have somewhat different hourly wind regimes.

North Carolina has several means of evening out differences between variable generation and load from hour to hour within days, but very limited ability to carry stored energy forward from day to day. The hydroelectric system is already used as a means to meet peak demands with a generation system heavily oriented toward baseload generation. In addition, there is pumped storage capacity in the Duke Energy system amounting to 2,100 MW, of which 1,360 MW has up to 24 hours of storage. In the summer, hourly storage is supplemented by the capacity of some large commercial customers to make ice in off-peak times and then run air conditioning systems without running the chillers at peak times in the afternoon and evening. In addition, the two largest utilities now have some 2,000 MW of load control arrangements.

As smart grids are developed, some customers will be able to respond to real-time pricing, offering still more opportunities to shift loads during the day. Still other storage opportunities may arise when plug-in hybrid vehicles are in use and have two-way communications with grid operators. With these possibilities in view, days and hours were examined in the data set in order to determine how many days and hours would need auxiliary generation, either by purchase from other systems or by (probably gas turbine) back-up generation within the system.

As the day totals in each of the four sample months were examined, it was apparent that the sum of solar and wind generation, day by day in each month were approximately normally distributed, with standard deviations running about one-fourth of the mean. In January, for example, mean daily generation for the month was about equal to the 80% specified above. Daily total power generation for the sample month of January as well as the hourly power generation for a sample day in January are shown here. Larger versions of these charts as well as charts for other sample months and another sample day are shown in the main text. Day totals varied, with about half the days showing above average generation and half below average. Within the below-average days, two-thirds were below average by a quarter or less of the mean. Only very rarely was the shortfall more than half the mean. Some days with above-average wind and solar generation still had hours when supplemental generation would be needed, but not often.

When all the days and all of the hours were considered, it appeared that auxiliary generation amounting to 6% of the annual total generation would be sufficient to fill in nearly all of the gaps between hourly renewable generation and hourly utility loads. The backup generation amounted to purchases from other systems up to 5% of hourly loads, and 2,700 MW of gas-fired capacity. There were 17 hours in the four months considered when still more backup power would be needed, or a loss-of-load probability of .0058

The out-of-system purchases or back-up generation in the system dropped the wind-solar contribution to 78% of the load. These results are shown in Table 1 of the main text (online at www.ieer.org/reports/NC-Wind-Solar.pdf. )

The important conclusion is that intermittent solar and wind energy, especially when generated at dispersed sites and coupled with storage and demand-shifting capacities of a system like North Carolinas, can generate very large portions of total electricity output with rather minimal auxiliary backup.

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XemaSab Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 10:30 AM
Response to Reply #93
94. I read that entire thing, and here's what I got out of it:
We'd still need to have gas and/or pumped hydro peakers with the capacity to provide over HALF the baseload.

Yes, they'd only be switched on to full capacity occasionally, but they would still have to be there.

Also, he makes assumptions that homes could be more energy efficient by 30% while also assuming that future technologies such as plug-in cars would only be charged at off-peak hours and might even supply energy back to the grid during peak hours.

He's also assuming that 1/4 again as much hydroelectric capacity can be installed, and that biomass can make up 12% of needs.

He also says, "In the 123 days examined, there was only one day when demand could not have been fully met with purchases of 5% and backup gas turbines at 2,700 MW capacity there was a shortfall in twelve of the hours of that day. There were two other days in which for two hours and three hours, respectively demand was not fully met. This indicates a loss-of-load probability of six tenths of one percent. U.S. utilities now use a planning process which aims at a much lower loss-of-load probability about .0003."

Also, "As the day ends, it becomes apparent that generation from the renewable sources has fallen short of demand by 55,491 MWh. This shortfall was met by a similar-sized draw on purchased power and generation from gas turbines. The hourly imbalances were covered by running the hydroelectric resources at strategic times, by the pumped storage facilities, the ice storage facilities, utility load control measures and the use of vehicle batteries."

I think the most disturbing part is the dude's reliance on pumped hydropower storage. I don't know how many systems in North Carolina have re-regulating facilities, but those would be needed in order to buffer peak flows on waterways. Also, reservoirs and their associated waterways used as peakers typically have a greatly reduced recreational value, which I'm sure wouldn't go over well in that state. Most reservoirs are used for flood control, and storing flows for electrical generation might interfere with flood control purposes.

Finally, I'm curious about how much all of this would cost. For an economist, it would be helpful for him to throw in some dollar figures.

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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 06:50 PM
Response to Reply #94
96. Let's take them one at a time...
Edited on Mon Sep-27-10 06:52 PM by kristopher
You wrote, "We'd still need to have gas and/or pumped hydro peakers with the capacity to provide over HALF the baseload."


Blackburn wrote:
"We are accustomed to systems for which time-of use pricing is available mostly to large commercial and industrial customers and to only a few residential consumers. Given the present patterns of generation, rates are lowest at night, when baseload capacity is running and demands are relatively low. This rate pattern is likely to be revised drastically in systems with large amounts of solar and wind capacity. Rates are likely to be lowest in the daytime, since the solar power component more than offsets the typically rising energy use as the day unfolds or at other times when renewable energy supply is greatest relative to demand." - p.22 (pagination from IEER hosted version of paper available at http://www.ieer.org )

and

"the absence of huge quantities of baseload power (none of which is included in this scenario) is of little consequence." - p.26



Since "baseload" power isn't part of the system, what are you trying to say?





Your post for reference.
I read that entire thing, and here's what I got out of it:
Posted by XemaSab


We'd still need to have gas and/or pumped hydro peakers with the capacity to provide over HALF the baseload.

Yes, they'd only be switched on to full capacity occasionally, but they would still have to be there.

Also, he makes assumptions that homes could be more energy efficient by 30% while also assuming that future technologies such as plug-in cars would only be charged at off-peak hours and might even supply energy back to the grid during peak hours.

He's also assuming that 1/4 again as much hydroelectric capacity can be installed, and that biomass can make up 12% of needs.

He also says, "In the 123 days examined, there was only one day when demand could not have been fully met with purchases of 5% and backup gas turbines at 2,700 MW capacity there was a shortfall in twelve of the hours of that day. There were two other days in which for two hours and three hours, respectively demand was not fully met. This indicates a loss-of-load probability of six tenths of one percent. U.S. utilities now use a planning process which aims at a much lower loss-of-load probability about .0003."

Also, "As the day ends, it becomes apparent that generation from the renewable sources has fallen short of demand by 55,491 MWh. This shortfall was met by a similar-sized draw on purchased power and generation from gas turbines. The hourly imbalances were covered by running the hydroelectric resources at strategic times, by the pumped storage facilities, the ice storage facilities, utility load control measures and the use of vehicle batteries."

I think the most disturbing part is the dude's reliance on pumped hydropower storage. I don't know how many systems in North Carolina have re-regulating facilities, but those would be needed in order to buffer peak flows on waterways. Also, reservoirs and their associated waterways used as peakers typically have a greatly reduced recreational value, which I'm sure wouldn't go over well in that state. Most reservoirs are used for flood control, and storing flows for electrical generation might interfere with flood control purposes.

Finally, I'm curious about how much all of this would cost. For an economist, it would be helpful for him to throw in some dollar figures.

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XemaSab Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 07:21 PM
Response to Reply #96
98. To spell it out for you like you're in first grade
there are two types of power plants: baseload plants and peakers.

Solar and wind would provide the baseload power.

That is, they would be producing power all the time when the wind is blowing or the sun is shining. Unlike a peaker, which is only switched on during periods of high demand.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 07:29 PM
Response to Reply #98
99. I understand that.
First, stop being rude.

Your point wasn't and still isn't clear; I can't address it if I don't understand it. Your "clarification" didn't add anything, so please explain.
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XemaSab Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 07:41 PM
Response to Reply #99
101. Never mind
n/t
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Kennah Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 07:08 PM
Response to Original message
97. Read "Sustainable Energy - without the hot air."
Read Chapter 18, "Can we live on renewables?", of the book "Sustainable Energy - without the hot air" by Dr. David MacKay.

Two conclusions he draws at the end of the chapter are:
- To make a difference, renewable facilities have to be country-sized.
- It's not going to be easy to make a plan that adds up using renewables
alone.


However, the numbers he's crunched layout right at the beginning of the chapter than the Brits are consuming 195 kWh per day per person and that renewables could add up to 180 kWh per day per person. That's 92.3% of consumption from renewables, in theory, if a massive country-sized investment were made in renewables.

I would suggest that perhaps the gap, and then some, could be filled through conservation.

Americans are much larger consumers of energy per capita so we'll have to engage in a whole lot more conservation than the rest of the globe.

David J.C. MacKay. Sustainable Energy - without the hot air.
UIT Cambridge, 2008. ISBN 978-0-9544529-3-3.
Available free online from www.withouthotair.com
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Sep-27-10 07:31 PM
Response to Reply #97
100. It is interesting the range of obstacles that exist for efficiency efforts
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Original message
102. Have you heard the bull**** claim that "renewables are great but they aren't enough" ? II
This is further proof that when nuclear proponents claim we MUST have nuclear power to provide "baseload" it is based on poor understanding of the relevant technologies. This particular study looks at integration of renewables into the grid.

Matching Hourly and Peak Demand by Combining Different Renewable Energy Sources
A case study for California in 2020


Graeme R.G. Hoste
Michael J. Dvorak
Mark Z. Jacobson

Stanford University
Department of Civil and Environmental Engineering
Atmosphere/Energy Program

Abstract
In 2002 the California legislature passed Senate Bill 1078, establishing the Renewables Portfolio Standard requiring 20 percent of the states electricity to come from renewable resources by 2010, with the additional goal of 33% by 2020 (California Senate, 2002; California Energy Commission , 2004). More recently, some legislative proposals have called for eliminating 80% of all carbon from energy to limit climate change to an acceptable level. At the passing of the 2002 California bill, qualifying renewables provided less than 10% of Californias energy supply (CEC, 2007). Several barriers slow the development of renewables; these include technological barriers, access to renewable resources, public perceptions, political pressure from interest groups, and cost, to name a few. This paper considers only one technological barrier to renewables: integration into the grid.

Many renewable resources are intermittent or variable by natureproducing power inconsistently and somewhat unpredictablywhile on the other end of the transmission line, consumers demand power variably but predictably throughout the day. The Independent System Operator (ISO) monitors this demand, turning on or off additional generation when necessary.

As such, predictability of energy supply and demand is essential for grid management. For natural gas or hydroelectricity, supplies can be throttled relatively easily. But with a wind farm, power output cannot be ramped up on demand. In some cases, a single wind farm that is providing power steadily may see a drop in or complete loss of wind for a period. For this reason, grid operators generally pay less for energy provided from wind or solar power than from a conventional, predictable resource.

Although wind, solar, tidal, and wave resources will always be intermittent when they are considered in isolation and at one location, several methods exist to reduce intermittency of delivered power. These include combining geographically disperse intermittent resources of the same type, using storage, and combining different renewables with complementary intermittencies (e.g., Kahn, 1979; Archer and Jacobson, 2003, 2007). This paper discusses the last method: integration of several independent resources. In the pages that follow, we demonstrate that the complementary intermittencies of wind and solar power in California, along with the flexibility of hydro, make it possible for a true portfolio of renewables to meet a significant portion of Californias electricity demand. In particular, we estimate mixes of renewable capacities required to supply 80% and 100% of Californias electricity and 2020 and show the feasibility of load-matching over the year with these resources. Additionally, we outline the tradeoffs between different renewable portfolios (i.e., wind-heavy or solar-heavy mixes). We conclude that combining at least four renewables, wind, solar, geothermal, and hydroelectric power in optimal proportions would allow California to meet up to 100% of its future hourly electric power demand assuming an expanded and improved transmission grid.

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ixion Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #102
103. Yep. I've heard that mythic piece of BS floated around...
It's a very popular meme amongst the alternative energy opponents, and it's complete and utter crap.
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Kolesar Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #102
104. public perceptions and political pressure from interest groups
It is our job to inform the politicians and newspaper writers.
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Nihil Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #102
105. Please don't spam the forum.
If someone else had posted this OP then it would have been a duplicate.

Seeing as how you posted it first time as well (and it's still on the
first page of E/E with recent replies) then it is an obvious attempt
to spam the forum (rather than just any thread that you dislike).
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #105
106. I was hoping to have a discussion without the spam from the pronuclear peanut gallery.
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madokie Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #106
111. +1
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Dead_Parrot Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #106
112. And how's that working out so far? nt
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XemaSab Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #102
107. Ass|U|Me
This analysis presents one method of estimating renewable capacities required to meet a certain percentage of California electricity demand. Additionally, we show that the complementary intermittencies of wind and solar power, when packaged with the flexibility of hydro and a baseload of geothermal, serve to sufficiently smooth the delivered supply from a renewable portfolio to allow it to follow demand throughout the day. Our optimized portfolio meets or exceeds demand in every hour of the year with existing hydro capacity and minimized surplus renewable generation3.1% annually for the 80% renewable supply. Our model, however, is only a first step. It relies on several simplifying assumptions and does not reflect many issues that would be faced in real-world design of an 80% or 100% renewable electricity supply. Three assumptions are briefly discussed below.

Assumption 1: The statewide distribution of wind and solar farms will remain the same as total capacity scales up. With the huge capacities arrived at in our resource portfolios, this heavy concentration of wind turbines in a handful of locations is unlikely. A more complete model could place smaller wind or solar thermal capacities at hundreds or thousands of locations across the state (and use several different wind turbine types). This would serve to reduce the variability in delivered supply even more, further easing grid integration of these resources.

Assumption 2: Hydropower has ultimate flexibility over a day as long as the nameplate capacity is never exceeded, and good seasonal flexibility as well. While our assumption of good hour-to- hour flexibility is reasonable, our model does not fully consider seasonal restrictions on hydro usage. Our optimized cases, for example, are far under average hydro usage in April due to the relatively low demand and high solar power output. To be under April hydro usage is fine, but it is not the case that all of the unused hydro can be shifted to the summer and fall, as is done in our model. This could only work with large reservoirs, while the April hydro capacity from small reservoirs should be used in April or discarded. A more complete model could build in better rules about seasonal shuffling of hydropower.

Assumption 3: Our analysis is performed only for the average day in each month. By averaging demands, wind speeds, and insolations over the month, we are removing much of the fine variability in output that worries grid operators the most. Our model shows that the complementary intermittencies of wind and solar and the balancing power of hydro can deliver a relatively smooth, peaking supply despite seasonal and perhaps even day to day variations in supply. But our model does not address the issue of hour to hour or sub-hour fluctuations in wind or solar output. To a large extent these will be dampened due to the combination of huge, widely distributed capacities over the state, but they will not be removed entirely. A good follow-up to this model would be to use modeled or measured wind speeds and insolations on several specific days, with as good temporal resolution as possible, to calculate the statewide power supply from this same resource mix. This could reveal the utility of the average as a forecasting tool, as well as the range of variability present in a real system.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #107
109. ALL analysis use assumptions, you are going to have to do more than that to support nuclear.
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exboyfil Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #102
108. When you drive through our wind farms
you will see a number of blades not turning. One major reason is the failure in the gear train. It is unusual to have a low speed high torque being converted to a high speed low torque for electrical generation. If one of these fails, then it becomes a service nightmare.

Several places are looking at a hydrostatic approach instead (combination of hydraulic pump and motor). If such an approach is successful, then most of the servicing on a wind turbine can be moved to the ground. A side benefit is that you can store energy in accumulators to help balance load.

This is an exciting area of research.
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madokie Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 09:12 AM
Response to Reply #108
110. I've often wondered why they didn't use this approach
use hydraulic pumps and motors and move the generators to the ground level. Many reasons to do that besides just getting rid of the gearboxes.
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txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 02:30 PM
Response to Reply #108
115. GE's new wind turbine does not suffer from that problem
Gears in today's wind turbines are the source of reliability problems. Get rid of the gears and they will be far more reliable.

Wind turbine manufacturers are turning away from the industry-standard gearboxes and generators in a bid to boost the reliability and reduce the cost of wind power.


Power ring: This three-megawatt wind turbine uses permanent magnets and a design that makes it significantly lighter than a conventional geared turbine.
Credit: Siemens


Siemens has begun selling a three-megawatt turbine using a so-called direct-drive system that replaces the conventional high-speed generator with a low-speed generator that eliminates the need for a gearbox. And last month, General Electric announced an investment of 340 million euros in manufacturing facilities to build its own four-megawatt direct-drive turbines for offshore wind farms.

Most observers say the industry's shift to direct-drive is a response to highly publicized gearbox failures. But Henrik Stiesdal, chief technology officer of Siemens's wind power unit, says that gearbox problems are overblown. He says Siemens is adopting direct-drive as a means of generating more energy at lower cost. "Turbines can be made more competitive through direct-drive," says Stiesdal.

http://www.technologyreview.com/energy/25188/
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exboyfil Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 04:21 PM
Response to Reply #115
116. Thanks for the information
As a fluid power guy I am a little disappointed but if they can get better efficiencies with this approach, then it is better for all of us.

Still some limitations with this approach as well. Big generator and magnets made from rare earth metals. This is the same problem we have with really efficient solar collectors (gallium selenium indiumetc). Interesting how the Chinese have locked up supplies of these metals. Recent news story talks about how they have stopped shipments to Japan. They are sitting in the catbird seat.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-28-10 05:44 PM
Response to Reply #116
117. No, they aren't.
They are the source for the not-so-rare rare earth elements not because no one else has any, but because demand has been so low that they cornered the market with cheap prices. If they don't want market share they can lose it in a heartbeat because these are actually extremely abundant resources - plenty of them scattered in enough places around the world to make market monopoly impossible.

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txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-29-10 09:38 AM
Response to Reply #117
131. Widely dispersed resources
So true. The Chinese are locking in access to the material resources that they know they will need in the future. They are acting purposefully, with a plan for the future. Gee, doesn't that sound like a good idea for a government to have such plans for the future? Meanwhile, our shortsighted Capitalist governments are aimlessly wandering this way and that, hoping that some big business will somehow begin to be responsible enough to make those plans for us.

Yet these resources are too abundant and can be obtained in too many places worldwide for anyone to "corner the market" in any of them or lock out all competitors. If one corners the market for an "easily obtainable" resource, someone will find a way to get more of it somewhere else. Perhaps new techniques or new technologies may be required. So what? They will be found or invented. That is what we do. These fairy stories of "scarce resources" hurting the renewable energy future are short sighted and easily disprovable.

They are false tales, meant to scare people away from moving full force into renewable energy. Much like the false tales about nuclear power that are meant to scare people away from nuclear power. Thorium reactors are safe, cannot be used to make bomb material, because they can't be used for bomb making they have not been studied much over the past 50 years so Thorium reactors are seen as "more risky" an investment --I say Thorium Reactors are the ONLY way to do nuclear power. Yes, as with all complex technologies that have been pushed to the wayside some attempts to commercialize Thorium Reactors will fail (just as some wind power projects have been canceled and some solar power plants have been canceled). That does not invalidate Thorium Reactors, solar or wind power at all.

Thorium cycle nuclear reactors are an important part of any sensible plan that can get us to energy security. Thorium is abundant as well, it is located in all countries of the world so the supply cannot be monopolized. Here, a UK article calls for a second Manhattan Project to bring the benefits of Thorium reactors to full potential and thereby end our dependence on fossil fuels forever:
"If Barack Obama were to marshal America's vast scientific and strategic resources behind a new Manhattan Project, he might reasonably hope to reinvent the global energy landscape and sketch an end to our dependence on fossil fuels within three to five years."
. . . snip . . .
Dr Rubbia says a tonne of the silvery metal named after the Norse god of thunder, who also gave us Thor's day or Thursday - produces as much energy as 200 tonnes of uranium, or 3,500,000 tonnes of coal. A mere fistful would light London for a week.

Thorium eats its own hazardous waste. It can even scavenge the plutonium left by uranium reactors, acting as an eco-cleaner. "It's the Big One," said Kirk Sorensen, a former NASA rocket engineer and now chief nuclear technologist at Teledyne Brown Engineering.
. . . snip . . .
Thorium is so common that miners treat it as a nuisance, a radioactive by-product if they try to dig up rare earth metals. The US and Australia are full of the stuff. So are the granite rocks of Cornwall (ed: in the UK). You do not need much: all is potentially usable as fuel, compared to just 0.7pc for uranium.

http://www.telegraph.co.uk/finance/comment/7970619/Obama-could-kill-fossil-fuels-overnight-with-a-nuclear-dash-for-thorium.html


Thorium is many times more abundant than Uranium, creates 200 times the energy pound for pound, and even creates far less hazardous waste. So why are almost all the nuclear power reactors worldwide based on Uranium and not on Thorium?
"After the Manhattan Project, US physicists in the late 1940s were tempted by thorium for use in civil reactors. It has a higher neutron yield per neutron absorbed. It does not require isotope separation, a big cost saving. But by then America needed the plutonium residue from uranium to build bombs.

"They were really going after the weapons," said Professor Egil Lillestol, a world authority on the thorium fuel-cycle at CERN. "It is almost impossible make nuclear weapons out of thorium because it is too difficult to handle. It wouldn't be worth trying." It emits too many high gamma rays."

http://www.telegraph.co.uk/finance/comment/7970619/Obama-could-kill-fossil-fuels-overnight-with-a-nuclear-dash-for-thorium.html


I encourage everyone to read the entire article referenced above.
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-29-10 09:55 AM
Response to Reply #131
132. You have to look at the entire package.
Edited on Wed Sep-29-10 10:26 AM by kristopher
The trouble with nuclear alternatives is that they ALL have drawbacks that are fatal to the widespread deployment of the technology. Thorium isn't used for a number of reasons, not because it hasn't been looked at. India has been trying to get their program moviing for decades, and so far their progress is not impressive.

IT is true to say thorium can *help* solve some of the problems associated with other fission technologies, but that overlooks the fact that other technologies can solve some of the problems associated with the thorium fuel cycle. There IS no single technology that solves all of the problems that MUST be solved before nuclear is deployed on the scale needed to make a meaningful contribution to the climate crisis.

Answer this - why spend more money on nuclear that requires more time to get less electricity?

There is no technical reason we need nuclear generated electricity to supplement renewable sources, so given the very high real costs, significant opportunity costs, and the unsolved (and likely unsolvable) problems associated with wastes and proliferation why do you think we should pursue it?
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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 12:28 PM
Response to Reply #132
133. If youir premises are flawed...your conclusions are flawed.
There is no technical reason we need nuclear generated electricity to supplement renewable sources, so given the very high real costs, significant opportunity costs, and the unsolved (and likely unsolvable) problems associated with wastes and proliferation why do you think we should pursue it?
===================================================================

IF your premises were true; there would be no reason. But you misrepresent
the facts. While nuclear has high initial costs, when done properly,
nuclear is 2nd cheapest only to coal - and that's without counting the
costs that coal externalizes.

The problems are NOT unsolved, nor unsolvable.

The IFR nuclear cycle solves the waste and proliferation problems.
The IFR is inherently safe or "passively safe", it doesn't produce
long term waste, and in fact will actually "burn" long lived actinides
from other reactors. Additionally, the spent fuel is impossible to
make into a bomb, as certified by the US's own nuclear weapons design
lab, Lawrence Livermore.

http://www.pbs.org/wgbh/pages/frontline/shows/reaction/interviews/till.html

Thankfully, President Obama has a Nobel Prize winning physicist as his
Secretary of Energy, Dr. Steven Chu. Dr. Chu will tell the President when
the "renewables" crowd is blowing smoke, and Dr. Chu supports the advance
of nuclear power. He's a smart guy.

Dr. Greg

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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Wed Sep-29-10 08:56 AM
Response to Reply #102
130. Wishful "thinking" or deciet??
Although wind, solar, tidal, and wave resources will always be intermittent when they are considered in isolation and at one location, several methods exist to reduce intermittency of delivered power.
-------------------------------------------------------

With the exception of wind; the others are coupled, even in remote locations.

For most of the night, when it is night on the East Coast, it is also
night on the West Coast. So where is this "redundancy" by location?
Unless you are stringing power transmission lines half way around the
world; moving to another location on the same continent doesn't buy
solar much needed redundancy. The same is true with tides and waves.
As far as the Moon is concerned, there's not much location difference
between the coasts.

Wind does have location redundancy; provided you build enough to have
excess capacity. Instead of having to duplicate capacity in multiple
locations; why not just opt for an energy source that doesn't have
the problem of being intermittent?

Dr. Greg

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TreasonousBastard Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Oct-03-10 10:36 AM
Response to Original message
137. Mine eyes glaze over from the real bullshit-- the pseudoscience in these "studies"...
and bringing that annoying thermodynamics legislation into the discussion.

Whatever solution is eventually found will be driven by economics-- technology will provide the choices, but that damn market will make the choices. Europe has tried to force renewables upon its population, but that has cost vast amounts of Euros for what might seem a miserable reduction in CO2 and pollutants. They might end up with a big sigh and look toward sequestering CO2 from their coal plants. No "Peak Coal" in sight.

Right now, and for the foreseeable future, nothing that could be considered renewable other than hydro can deliver electricity at a cost per kilowatt as low as fossil plants can. And we have exploited hydro as far as we can.

So, we slowly fool around with wind and other generation for a while until there's the Great Breakthrough that makes it cheap and worthwhile, and we find ways to deal with coal emissions, and we play with nuclear, although it's become very expensive and the fuel may be hard to come by.

I am personally in favor of rationing-- everyone gets a certain amount of kilowatts per month at an agreed price, and everything over that maybe five times the cheap price. But I suspect I wouldn't get too far pushing that, even though we've already got a foot in the door with smart meters and variable rates.

Even more horrific would be the concepts of gas and water rationing, but we might get there.



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DrGregory Donating Member (427 posts) Send PM | Profile | Ignore Sun Oct-03-10 11:37 AM
Response to Reply #137
139. I wouldn't go to far down that road...
I am personally in favor of rationing-- everyone gets a certain amount of kilowatts per month at an agreed price, and everything over that maybe five times the cheap price. But I suspect I wouldn't get too far pushing that, even though we've already got a foot in the door with smart meters and variable rates.
=========================================================

If your solution is rationing and then charging high rate premiums
above the ration level; then I wouldn't go to far down that road.

The US public has not supported such schemes in the past. The public
won't support a system of limited production that has to be rationed.

If rationing is the end result of a limited production system; the public
will demand that the production levels increase to sate their appetite.

Dr. Greg

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