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Sun Oct 28, 2012, 04:01 PM

 

The big question mark over gasoline from air

12:10 22 October 2012 by Paul Marks

In a shipping container on a British industrial park, not far from where George Stephenson launched the world's first steam railway in 1825, another transport revolution might be beginning. Every day the machinery inside produces half a liter of purified gasoline. It sounds humdrum until you realize one thing: the only raw material used is air.

Last week, Air Fuel Synthesis (AFS), a company in Stockton, UK, revealed the first successful demonstration of an idea that dates back to the oil crisis of the 1970s: that carbon, hydrogen and oxygen can be plucked from carbon dioxide and water in air to be converted into methanol and then morphed into gasoline.

However, amidst the headlines, some media coverage overlooked the key point: the energy efficiency of the process has yet to be demonstrated. This matters because the technique uses electricity for key stages. It should not require more energy input than is gleaned from burning the fuel it produces.

The big idea is to capture atmospheric CO2 and turn it into fuel so there's no net increase in CO2 from cars and trucks fueled by such gasoline. As long as the process is powered by renewable electricity sources such as solar, wind or tidal, using the gasoline is carbon neutral.



http://www.newscientist.com/article/dn22407-the-big-question-mark-over-gasoline-from-air.html

25 replies, 2561 views

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Arrow 25 replies Author Time Post
Reply The big question mark over gasoline from air (Original post)
ROBROX Oct 2012 OP
Angry Dragon Oct 2012 #1
VMA131Marine Oct 2012 #3
Angry Dragon Oct 2012 #4
ToxMarz Oct 2012 #5
NickB79 Oct 2012 #14
sofa king Oct 2012 #16
liberal N proud Oct 2012 #2
caraher Oct 2012 #8
Warpy Oct 2012 #6
krispos42 Oct 2012 #9
jeff47 Oct 2012 #12
krispos42 Oct 2012 #15
jeff47 Oct 2012 #17
krispos42 Nov 2012 #21
jeff47 Oct 2012 #13
caraher Oct 2012 #7
Confusious Oct 2012 #10
jeff47 Oct 2012 #11
NoOneMan Nov 2012 #23
jeff47 Nov 2012 #24
NoOneMan Nov 2012 #25
Bosonic Nov 2012 #18
caraher Nov 2012 #19
Bosonic Nov 2012 #20
eppur_se_muova Nov 2012 #22

Response to ROBROX (Original post)

Sun Oct 28, 2012, 04:07 PM

1. could coal plants use this process??

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Response to Angry Dragon (Reply #1)

Sun Oct 28, 2012, 04:13 PM

3. There wouldn't be much point ...

It would be far much efficient to supply the renewable power directly to the grid than create an intermediate fuel. However, this may be a way to store energy to make up for times when the availability of renewables is low in relation to demand from the grid. Even using this process to create liquid fuel for vehicles is very inefficient in comparison to using the power to charge a battery in an electric vehicle. But, liquid fuels are much more convenient for energy storage due to their much greater energy density than batteries.

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Response to VMA131Marine (Reply #3)

Sun Oct 28, 2012, 04:17 PM

4. What I meant to capture the Co2 that coal plants spew out

unless I am not understanding the process

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Response to Angry Dragon (Reply #4)

Sun Oct 28, 2012, 04:27 PM

5. Co2 is fungible

If the coal plant is putting Co2 in the air and this process is removing it, it is the same effect. Doesn't need to identify the specific Co2 molecules from the coal plant.

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Response to Angry Dragon (Reply #4)

Tue Oct 30, 2012, 02:10 PM

14. You could. Some algae-to-biodiesel proposals suggest coal plants as a CO2 source

To grow their algae in vats.

The problem is that we can't afford to keep burning ANY coal if we want to salvage this civilization, even if the carbon is (temporarily) diverted into another fuel before being released into the atmosphere. All coal plants, most oil-burning vehicles, and most nat. gas plants as well, need to be shut down in the next few decades to stand a snowball's chance in hell of keeping some civilization left on this planet.

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Response to Angry Dragon (Reply #1)

Wed Oct 31, 2012, 01:41 AM

16. That would be as silly as diluting gasoline with alcohol.

Which we also do, so probably yes.

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Response to ROBROX (Original post)

Sun Oct 28, 2012, 04:12 PM

2. Suck the hydrocarbons out of the air.

Hmmm!

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Response to liberal N proud (Reply #2)

Mon Oct 29, 2012, 12:40 AM

8. Nope

Sucking CO2 out of the air. Burning hydrocarbons (i.e. compounds containing hydrogen AND carbon atoms) produces the greenhouse gas carbon dioxide. This would use energy to suck CO2 out of the air and produce hydrocarbons. The energy stored in those hydrocarbons could then potentially be released again by burning them (which would again produce CO2).

Contrary to the suggestion of the article, they will NOT be able to store more energy for potential release by burning the fuel than they put into creating the fuel from the CO2 in the air. If that were possible, then they have created a perpetual motion machine. I see no reason to believe they can do this.

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Response to ROBROX (Original post)

Sun Oct 28, 2012, 05:45 PM

6. That's one thing they did point out, that it's not economically feasible

and that usually means it sucks more energy than it produces.

However, were that energy to come from something like a solar tower, that might not be the case forever.

It might be better, however, to use the energy from the solar tower to perform hydrolysis, liberating oxygen and hydrogen for use in fuel cells.

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Response to Warpy (Reply #6)

Mon Oct 29, 2012, 01:28 AM

9. Problems

Zapping water with electricity isn't very efficient. As I recall, you only recover 25% or so of the energy you pump into the water to spit the molecule.

Also, there's almost no vehicles out there that use fuel cells. Billions use gasoline, though.


This might be the answer for "how the hell do we access all that cheap wind and solar power in the Midwest and Southwest?"


Wind turbines and solar arrays turn air into gasoline. We fill up tanker trucks and let the Midwesterners and Southwesterners burn air-derived gasoline. Tens of millions of people will begin burning "renewable" gasoline.

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Response to krispos42 (Reply #9)

Mon Oct 29, 2012, 09:52 AM

12. Don't need tanker trucks

We already have thousands of miles of pipelines.

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Response to jeff47 (Reply #12)

Wed Oct 31, 2012, 12:00 AM

15. Yeah,but they have to be close by the plants...

...which would be out in the middle of nowhere turning wind and solar into gasoline on land that's not being used otherwise.

I'm not saying they couldn't be built, but it would be much faster to simply use the existing road network and keep the deliveries local. Maybe each plant built could supply all the gas stations within 100 miles, and that would be performed by a few tanker trucks making regular runs.

A distributed network of conversion plants across the Midwest and Southwest could ultimately supply 100 million people with automotive fuel, cutting our fossil fuel consumption by a significant portion.

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Response to krispos42 (Reply #15)

Wed Oct 31, 2012, 08:34 AM

17. One can extend the pipelines as needed

And if you're distributing via truck, that vastly reduces your output - the truck's burning your output while it drives thousands of miles.

but it would be much faster to simply use the existing road network and keep the deliveries local.

Except that's not what you were just talking about - you were talking about using the ample solar power in the southwest to produce the fuel.

A distributed network of conversion plants across the Midwest and Southwest could ultimately supply 100 million people with automotive fuel

Except that you can't do that with "local deliveries".

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Response to jeff47 (Reply #17)

Sun Nov 4, 2012, 01:10 AM

21. My concept is that each plant starts out small...

...as benefits an emerging technology. The plant is built near a wind farm, and draws power directly from that.

Maybe they build a gas station right on the property to promote their product. Owned by the same company that runs the plant.


Anyway, the low-production first plant would produce gasoline and store it. When it produced enough for a tanker truck, the truck would transport the fuel to area gas stations, if their contracts would allow it. If not, hey, attached gas station right there. Simply lower the prices until people are driving miles out of their way to buy cheap gas.


As the technology scales up, subsequent plants would be built. Maybe new ones would make a tanker of gas a day, instead of a tanker of gas a week. More plant-owned gas stations are built; maybe a few independently-owned local stations dump their fossil-fuel provider and go with eco-gas instead.

Eventually, you reach the point where wind farms are being made simply to power large conversion plants that produce more gasoline then can be produced locally. At which point you start building pipelines.




Alternately, you can miniaturize the technology such that a gas station actually produces the fuel it sells. Instead of a c-store and a 4-bay garage, you'd have a pile of equipment wired to the grid that makes, say, 2,000 gallons a day or whatever.

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Response to Warpy (Reply #6)

Mon Oct 29, 2012, 09:55 AM

13. Hydrogen is a problem

It's very small, so it leaks through any tank.

So far, the only major user of hydrogen power has been the space program, and they top-off the hydrogen tanks until the moment the vehicle launches.

Hydrocarbons of some sort are far more practical because their larger size avoids this problem.

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Response to ROBROX (Original post)

Mon Oct 29, 2012, 12:36 AM

7. No question mark

This could become useful either to capture CO2 from the air or as a means of converting electricity into liquid fuel. Maybe. But the author of this piece sets the bar impossibly high:

It should not require more energy input than is gleaned from burning the fuel it produces.


If it does THAT, I think they've overturned the laws of thermodynamics...

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Response to caraher (Reply #7)

Mon Oct 29, 2012, 05:09 AM

10. The author should have said something else

Like "It should not require burning more hydrocarbons then it produces."

I kinda think that's what they were going for, but science reporting being what it is...

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Response to ROBROX (Original post)

Mon Oct 29, 2012, 09:51 AM

11. They're wrong.

However, amidst the headlines, some media coverage overlooked the key point: the energy efficiency of the process has yet to be demonstrated. This matters because the technique uses electricity for key stages. It should not require more energy input than is gleaned from burning the fuel it produces.

This is wrong.

First, we know the resulting fuel will have less energy than it took to make the fuel. Thermodynamics still works.

Second, it doesn't matter.

The point of this process is energy storage, not energy production. Battery technology has been creeping along for 50 years. With that track record, we're not likely to get a great leap ahead any time soon. And we need a leap for practical electric vehicles - current models work for some people, but a lot of people can't really use them due to range or "refueling" constraints.

Enter "make gasoline from air". That gas lets you capture energy from a fixed location and use it in a mobile platform. Effectively, you can make a "nuclear-powered car" - or wind, or solar, or any other power source. (And it won't be as horrifically bad an idea as the "nuclear-powered car" from the 1950s)

I really don't understand all the people demanding that this process somehow generate energy. We know how to generate energy cleanly, efficiently and cheaply. What we don't know is a practical way to store that energy in a way we can use in vehicles.

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Response to jeff47 (Reply #11)

Mon Nov 5, 2012, 11:49 AM

23. But here is the rub

 

If we want to use this as energy storage for wind and solar, we still have to invest energy (burn oil) into building wind and solar infrastructure in the first place. And now this is yet one more moving part to the energy system that we have to create infrastructure for. It would basically take decades for any of this to become carbon neutral or even energy neutral if you consider the initial dirty energy investment.

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Response to NoOneMan (Reply #23)

Mon Nov 5, 2012, 02:13 PM

24. So since it won't pay of instantly, we should just keep burning stuff like always?

There are no magic bullets for problems the scale of global climate change. There are a series of relatively small improvements that will add up over time.

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Response to jeff47 (Reply #24)

Mon Nov 5, 2012, 02:43 PM

25. Keep burning stuff like always opposed to burning more stuff like always?

 

There is only 2 ways to invest in green energy:

1. Burn more fossil fuels to power the production process
2. Mandate oil burning levels remain the same, thereby reducing the amount of energy available for traditional economic growth.

Which do you prefer (hurt the environment more in short term or throttle economic growth)? Which do your chosen leaders prefer?

How can you guarantee that post production, when available energy levels increases (thereby making the average price of energy decrease), *all* energy wont be used to fuel economic growth? That tends to be the human trend? Do you, after the time of new energy creation, plan to throttle energy usage as to ensure only green energy is used? Do you believe energy usage can be throttled? Is there a political will for it? Why don't we do it now?

So much of this "green" energy debate presents this same false dichotomy without even thinking about the initial energy investment. There is never a 3rd option presented of stop using so much damn energy!

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Response to ROBROX (Original post)

Thu Nov 1, 2012, 08:05 PM

18. Alternatively (and probably more efficiently)

CO2 can be extracted from seawater (http://pubs.rsc.org/en/Content/ArticleLanding/2012/EE/C2EE03393C), where it exists at a much higher concentration than in the atmosphere. The CO2 depleted oceans will reach a new equilibrium with the atmosphere; indirectly removing CO2 from the air.

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Response to Bosonic (Reply #18)

Thu Nov 1, 2012, 11:30 PM

19. Interesting idea...

How does the 242 kJ/mol to extract carbon dioxide from seawater compare to the air technique? (The article in the OP gives us no good way to tell...)

Also, I think that while there's much more carbon in seawater than air per unit volume, there's actually more CO2 in air when you look on a ppm basis. I'm not sure which metric would more relevant here...

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Response to caraher (Reply #19)

Fri Nov 2, 2012, 03:33 AM

20. Don't know the energy requirements of the air technique either

Just going off the volume of air/seawater required to be processed for a given amount of CO2, hence the probably.

Also, CO2 concentration is higher in colder water, so north Atlantic/Pacific would be good choices.

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Response to ROBROX (Original post)

Sun Nov 4, 2012, 10:41 AM

22. More of an E&E post ...

(FWIW, I'm willing to bet the energy efficiency will be excruciatingly low. No mining operation can break even if the ore is not rich enough. If you want surface carbon, biomass may be the only sufficiently concentrated source, and not a particularly efficient one.)

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