Now here's a dangerous and dumb idea: Small scale hydropower.

[NNadir]

"IDAHO FALLS, Idaho - A scientist says the United States could more than double its hydropower supply by harnessing the energy of smaller streams.


Doug Hall with the Idaho National Engineering and Environmental Laboratory said the feat can be achieved using small turbines or generators instead of dams. Small-scale hydropower, he said, could help the country meet its energy needs while reducing pollution and the need to import fossil fuels.


"There is a huge untapped resource in the U.S.," Hall said. "Our project's mission is to lead and facilitate the next generation of hydropower, which will be small, distributed hydropower without the use of dams because of their environmental impacts..."

http://story.news.yahoo.com/news?tmpl=story&cid=624&ncid=624&e=4&u=/ap/20041019/ap_on_sc/small_hydropower_2

Just what we need, point source destruction of small free flowing streams.

[doubleplusgood]

1. micro-hydro in the downspouts

Maybe this could be a viable option, at least in the Pacific Northwest if all homes were equipped. All that water falling from the sky from October through May could produce a nice chunk of power for the grid.

[Philostopher]

2. Cripes -- they think the amphibians are disappearing

quickly now -- imagine how fast they'll disappear once we start damming even the small streams.

Now, small-scale hydro in artificial waterways, like drainage ditches, guided runoffs and the like, maybe.

[TreasonousBastard]

3. Actually...

up until the 30's, and large utilities being formed, mnay small towns in the Northeast had their own local hydropower projects that worked very well.

Granted that building more dams could cause problems, but there are thousands of dams already built that could be converted and upgraded.

[bemildred]

4. John McPheee wrote a nice book on minihydro power.

If wind and solar are good, minihydro is good, and geothermal
can be good, and you don't have to kill the frogs either, think
waterwheels grinding your grain into flour and stuff, think
windmills. Small is good. Which is not to say that somebody won't
botch it, but it's not nukes and it's not hyrdocarbon burning.

[NNadir]

5. Nukes, big giant nukes, are far better than hydropower by a long stretch.

Small is NOT good in energy, with possible exception of windmills. This is because small energy systems are very difficult to regulate. Moreover the materials used for them often represent point source pollutants, the most difficult to contain.

I have a small stream next to my house on my neighbor's property. I very much doubt that if he dammed it, he would even have the remotest clue about the environmental impact, or for that matter the safety of my chidren.

Earlier this year several private dams here in New Jersey failed during a rain storm cause millions upon millions of dollars in damage. No insurance and no liability, as no one could tell who the dams belonged to.

[brokensymmetry]

6. I've got a question.

How much Uranium do we have left, given current consumption rates? And, if we did build lots of nuclear plants, how much Uranium would we have?

I'm under the impression that the available supply may be rather modest...and that the fast breeder reactors haven't been very successful.

[NNadir]

9. Uranium and Thorium resources exist to last about 3000 years.

Historically there was much concern that resources were much smaller, but it is now known that Uranium is about as common as Tin and measures in billions of tons. (Uranium thus far consumed in nuclear reactors is less than ten thousand tons.) Thorium resources now known dwarf Uranium resources by a factor of nearly ten.

The resources in the fissionable isotope Uranium-235 are more modest, about a hundred year supply. Historically, people thought this placed limits on the extent to which nuclear would be available. However the use of a Thorium based fuel cycle with Uranium as a diluent for U-233, high burn-ups and a few fast fission based reactors, will allow for the consumption of 100% of the fission resources including both the fissile and fertile nuclei.

These figure are based on nuclear energy supplying 100% of the future world energy load expected to stabilize at around 1000 exajoules in 2050. The extent to which renewables can displace nuclear, to which energy can be conserved and to which population reduced will extend Uranium and Thorium resources farther into the future. The extent to which fusion can be developed will also extend these resources, perhaps almost indefinitely, although it seems very likely that fusion reactors will require the assistance of at least some fission reactors to operate.

[TO Kid]

12. U-238 is also fissionable

The nukes that provide a third of the power in Ontario are Candu reactors that run on U-238 and heavy water.

[jpak]

13. LOL!

CANDU reactors use unenriched uranium (~0.7% 235-U).

238-U is NOT fissionable.

[jpak]

14. US uranium production is in steep decline

http://www.eia.doe.gov/emeu/aer/txt/ptb0903.html

http://www.eia.doe.gov/cneaf/nuclear/dupr/qupd.html

US uranium concentrate production peaked in 1980 (~44 million tons per year)

Domestic U production has declined to ~2 million tons per year today.

The US nuclear industry currently uses ~50 million tons of uranium concentrate per year.

Imported uranium comprises ~96% of current US uranium consumption.

[NNadir]

15. This is mainly because the price of Uranium is so low, $13/kg US.

Thorium is (since being eliminated from gas mantles) simply thrown away after the Lanthanides from Monzanite is removed.

Basically, on the basis of cost of fuel per watt - the same calculation that people use when they claim that "solar energy is free," Uranium is too cheap to meter.

In fact, Uranium and Thorium are so plentiful that many generations will pass before it can be depleted.

All of this is excellent news of course.

By the way, the US nuclear industry does not "use" 50 million tons of Uranium per year. First off, looking at your links, you really need to make a distinction between pounds and tons. A pound is 1/2000 of a British ton. In any case the energy contained in 50 million tons of Uranium (which would represent about can easily be calculated as follows. A typical fission releases roughly 200 MeV. 1 MeV = 1.602E-13 Joules. There fore the fission of one mole (6.02E23 atoms) of Uranium releases 200 X 1.602E-13 X 6.02E23 = 1.93E13 Joules. One mole of Uranium weighs roughly 238 grams, meaning that the fission yield of totally fissioned Uranium is 1.93E13/238 = 80 billion joules per gram. One pound is roughly equal to 454 grams meaning that one pound of Uranium contains 80 billion X 454 = 3.68E13 Joules. This means that one ton of Uranium completely fissioned is 3.68E13 Joules X 2000 = 7.36X16 Joules.

On the entire planet right now, the energy demand per annum is generally thought to be around 400 exajoules.

http://www.pnl.gov/energy/climate/climate_change-technology_scenarios.pdf

Since an exajoule is 1E18 joules, we see that the entire energy demand of the planet would be met, if all of coal mines, oil fields, wind fields, hydroelectric plants were replaced by nuclear plants, by 400E18/7.36E16 = 5440 British tons of Uranium, completely fissioned (some as intermediate Plutonium). This differs from 50 million tons by a factor of 10000. Maybe the nuclear industry is boiling off the atmosphere in the night when no one is looking, say when they're playing pirates in the high seas off Greenland.

Oh well LOL, maybe LMFAO even.

Actually, the nuclear industry only burns about 3 to 5% of the Uranium it puts in the fuel in a given reactor. Thus we see that the industry actually would, if called upon to produce all of earth's energy now, would have in reactors at a given time 5000/0.04 = 125000 british tons. 95% of what came out of the reactor would of course be recyclable, and 5% would be fission products.

Oh, and when you announce that U238 is not fissionable with a knowing snicker, you really ought to specify the speed of the neutrons doing the fissioning. It is true the capture to fission ratio of Uranium-238 is quite low in thermal reactors such as the CANDU, roughly around 1%. However in fast reactors, this ratio approaches 30%, and a considerable number of fissions (and thus a high proportion of the energy) comes from fission of U-238. This behavior is pretty typical of the actinides in general. Np-237, as I'm sure you know, has a thermal neutron capture to fission ratio even smaller than U-238, but has a 40% capture ratio with 1-2 MeV fast fission neutrons. Therefore one can almost obtain criticality with Neptunium, depending on the value of eta, so long as one chooses a point in the spectrum where the capture ration is high and eta is high.

This property of variable cross sections over a range of fission speeds represents the reason why the transuranic distribution of elements in a continuously recycled fast neutron spectrum would have less than 2% Curium and less than 2% Americium, whereas using a thermal spectrum, we would be able to obtain an equilibrium concentration of almost 8% Americium, 30% Curium, with a little Californium thrown in on the side. (Please see Prog. Nucl. Energy, 31, 13, (1997))

But thanks anyway for pointing out that nuclear fuel is really, really, really cheap.

[bemildred]

7. I don't share your anxieties.

I like decentralized solutions.
Let's just disagree.

[Ready4Change]

8. Dams? Article says hydro WITHOUT dams.

I think the idea is to drop a number of small turbines into a stream, rather than dam the whole stream and feed it into a single huge turbine?

It sounds to me like it would be less disruptive to wildlife, allthough it would certainly be a bad thing for any frog that works its way into the turbine housing.

[midnight armadillo]

10. Microhydro does NOT USE DAMS

You just need a diversion pipe to the turbine, or if the stream is deep enough an immersion turbine can be used.

No dams are necessary.

They're great since for off-the-grid use they're the most economical source of electricity for battery charging. Try www.altenergystore.com as a starting point for more info.

NNadir, I'm not sure why you're so wedded to the idea of a massive national electrical grid infrastructure. It's useful in many ways, but most homes could go off-grid completely.

[hatrack]

11. Not necessarily

Lots of microhydro is really and truly micro. Some of the generators are about the size of trolling motors, and require the diversion of only a few gpm, or at most a few dozen gpm, typically through a length of PVC pipe. The water is then returned to the stream at the end of the pipe.

If you look in magazines like Home Power & Solar Today, you'll see a fair amount of information on these systems. The focus is (not surprisingly) for off-grid houses & remote farms.

Naturally, since there are only so many pieces of property with the right streams, correct gradient and so forth, I doubt this is going to generate gigawatts of power, but the distruptions are pretty minimal.

[Oggy]

16. I was going to reply to the NNadir

But you've summed it up. Instead here is a press release from the company I work for in the UK, regarding one of the first such projects set up in part by us. I guess over in the UK we do have many streams already diverted for old mills so impact is even more negligible.

"Wheels of fortune
Unique hydro-power project launches in south Somerset

The UK’s bid to produce sustainable energy and increase energy efficiency was given a significant boost today with the launch of Britain’s first micro-scale water mill hydro-power project.

Located in south Somerset, 10 historic water mills will generate enough hydro-electricity to supply 150 homes in the area, with surplus energy sold back to the power companies.

Led by the Council and part-funded by the Energy Saving Trust’s Innovation Programme , the scheme integrates energy efficiency with renewable power. At full capacity, the mills will produce over 600,000 kWhr of electricity per year, reduce carbon dioxide emissions by 260 tonnes, helping the Government meet its target to produce 10 per cent of electricity from renewable sources by 2010.

Spearheading the mill consortium, Gants Mill, near Bruton, is the first to generate electricity when its turbine is switched on this afternoon by BBC TV presenter Adam Hart-Davis. The other mills will come ‘on stream’ by summer.

With at least 20,000 disused mill sites in the UK, there is vast untapped potential to harness river and stream power to help meet Government renewable energy targets. The south Somerset project showcases how local authorities and their communities can work together to combat climate change.

Energy Saving Trust Head of Community Partnerships, Catriona Reeby, said: “This Somerset hydropower scheme demonstrates how, with a little ingenuity and imagination, local authorities and communities can work together to initiate significant carbon saving schemes. If every local authority developed one such innovation scheme we could save nearly 110,000 tonnes of carbon per year. It’s an inspirational project and one that we need many more of.”

South Somerset District Council Environmental Officer, Keith Wheaton-Green, said: “I am delighted to be here today to mark the official launch of the project. Today is the culmination of three years’ working alongside the South Somerset Hydropower Group.” "

[Nihil]

17. Good one!

Hope things go well for your company. This is the sort of small-scale
operation (comparatively) that could be put in place across much of
Britain at the community level (rather than the national level).

Do these schemes only work with overshot mills (steep local gradient)
or do they work with undershot ones (simple river flow)?

There's an old undershot mill near me that is now a restaurant.
Wonder if they'd be interested in cutting their power bills (and those
of the pub next door)?

Nihi

[Oggy]

21. Both I think

:-)

[hunter]

18. Solar seems easier to me.

But I've always lived in arid or flat places.

The rivers and streams I'm most familiar with tend to get rough -- when they flood the water moves big rocks and branches and anything else in the way. It's difficult to build a simple "river well" that will survive that, much less a small power plant.

Every power source has its problems. If a mill site has survived a century or more, and the ecology of an area has stabilized around that, certainly, put a micro-power plant there. But adding thousands of new micropower plants to rivers and streams that have never been "domesticated" would be a very bad thing. I've already seen too many ugly PVC pipe and cable contraptions strung across streams and rivers.

These things don't last, and they probably won't pay back the energy, or the human effort, put into them.

[NNadir]

20. It takes 10 liters of water falling almost one meter each second to light

one one hundred watt light bulb at 100% efficiency.

My neighbors have a small stream on their property, in a ravine. I can see it from my living room window. If they tried to light one light bulb (and in turn each of the neighbors downstream tried to repeat the feat) it would destroy that stream.

[jwirr]

19. In the new magazine "Ode"

there is an article regarding ocean waves used to make electricity in Norway and Scotland. The devices used are small and do not impact the environment. For our coast lines and possible for the great lakes area that might be an answer.