Storing wind-generated energy as gravitational potential energy?

Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive.
So why not store the energy as gravitational potential energy?
E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need?
??
Parts would need replacing far less often than batteries.
John
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John Nagelson wrote:

They already use water as the large weight, is anything practical? Just over 1kWh from 4 tonnes lifted 100m (excluding losses).
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True that (mass) x (g) x (height) = (required power) x (time) gives large figures for (mass) x (height).
But maybe with concrete or old cars? Or maybe store some as elastic potential energy? I'm only thinking about at a domestic level.
John
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wrote:

True that (mass) x (g) x (height) = (required power) x (time) gives large figures for (mass) x (height).
But maybe with concrete or old cars? Or maybe store some as elastic potential energy? I'm only thinking about at a domestic level.
John
____
Take a read of chapter 4 of Prof David Mackays fantastic book on sustainable energy: http://www.inference.phy.cam.ac.uk/sustainable/book/tex/cft.pdf (10 meg download)
I think actually harvesting sufficient wind energy in the first place is problem zero.
D
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John Nagelson wrote:

When you look at energy density, for any form of storage of usable energy, you find a scale, and the lowest on the scale is mass times height systems.
Much better is mass times velocity squared, and heat. Both of those can be large in small spaces and volumes. At moderate heats too.
Then comes chemical energy, liquid fuels, batteries and the like. Things start to get pretty compact. Self contained portable power units of sensible dimensions become possible.
At the top of the scale is nuclear energy.

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John Nagelson wrote:

Getting four tonnes of material isn't a problem.
But what mechanism have you got that would raise that four tonnes 100 metres straight up?
Or 40 tonnes 10 metres?
Or 400 tonnes one metre?
The raising and lowering has to be a) safe; b) controlled; c) connected to some sort of generator.
And all that for a measly 1 kWh.
Maybe if you had an arrangement which used your whole house as the weight? But the cost of making it (in financial and resources terms) would be prohibitive.
--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
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Rod wrote:

I haven't got one, I was just pointing out the scale of the problem

Exactly.
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On Sun, 07 Dec 2008 17:09:00 +0000, Andy Burns wrote:

The only place I've seen this work is in an LED standard lamp - you manually lift a mildly heavy weight from floor to 5' off the ground, then it falls slowly while running a generator (through a gearbox) for a couple of hours.
If you're seriously looking at this sort of thing you need to get your whole house consumption down from 1kW average (what ours is while occupied, TV on etc.) to a few hundred watts at most.
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John Nagelson wrote:

a persistant myth http://www.wiki.diyfaq.org.uk/index.php?title=Lead_acid_battery_construction

how would you arrange gearing? Or would you have it only charge when half max windspeed were reached, and throw away any extra energy at higher speeds?
Have you calculated what mass and height you'd use?
NT
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snipped-for-privacy@care2.com wrote:

Fiddle with the numbers in google calculator
http://google.com/search?q =(3675+kg)+*+(9.81+((meters+per+second)+per+second))+*+(100+meters)+in+kilowatt+hours
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On 7 Dec, 15:42, snipped-for-privacy@care2.com wrote:

This is crazy.
I am far from an elfinsafetee fan. So, OK for a few-off cells by someone technically competent - but on a 'home-industrial" scale? That is idiotic.
It is bulk H2SO4 you would be playing with. Have you ever had a sulphuric acid burn? Even a small spot stings like hell and it takes weeks for the scar to heal. Not to mention the mass of volatile ions being spurted into the air Could you be sure you could contain it safely? AND be sure no idiot tests the water with their finger.... Solve all those problems and you'd still have potential risks from lead contamination of the househild environment.
Car batteries are surrounded by a rugged rubberised casing & sealed, but even so cases have been known to split.
Have you calculated how much you need to store 10 to 20 KWhr (typical household daily elec requirements excluding space heating)? How much space it would take? And there is all the trouble of handling a DC supply.
However running a wind generator to heat the domestic hot water directly might be feasible depending on the costs of suitable generator (s). That could store the generated energy quite nicely, but as with all such schemes you would have to accept lack of hot water when you need it most (eg during a run of windless mid-winter days with no cloud cover).
It might be possible to extend such a scheme to space heating and to charging electric car batteries, but same objections apply. Even then you'd find extensive costs when it comes to implementation,
Wind is popularly regarded as "free" energy. But it is no cheaper than the oil and coal lying free underground. Just like for coal and oil, spending starts when you start to build & run the infrastructure to extract the energy.
Alas, an idiot's "don't try this at home" message needs appending to the wiki article: as if anyone could be so stupid...
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We were somewhere around Barstow, on the edge of the desert, when the
saying something like:

Ah right; those thousands of people who are living off-grid with medium to large battery banks must all be living in fear and trembling of getting burnt or blowing up. Hint: we're not all as stupid as you think we are.
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wrote:

what constructed as shown in the wiki article?
If you mean properly a constructed robust and sealed lead acid battery bank (as used in telephone exchanges) then no problem: but the poster pointed at the wiki article as the way to do it. He is welcome to the experience - for as long as he can drag it out..
//
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wrote:
(Can't believe I'm actually replying to this...)

Well, in the case of my house's UPS, that's 24 volts at 1000 amp-hours. I got the 20 AGMs as a matched but used set as scrap from an AVS electric bus battery pack.
A good alternative is a 48 volt, 500 amp-hour fork-lift battery. They're recycled when they fail to run a whole shift. That is, with most of their life remaining. Again, easily purchased for scrap value which is currently about 5 cents a pound.

Well, this whole thread is silly and those of us who can do simple math are just funning around. Anyone who thinks that they're going to supply their house with 20kWh of wind power on a daily basis cheaper than the utility power is smoking something MIGHTY FINE!
My UPS is grid-charged and is here for the week-long outages we frequently have in the winter up here in the mountains. As far as hassles, there are none. The main UPS is over 15 years old and has never needed even its ears scratched, much less any attention. AGMs don't need attention and don't leak acid so no corroded connectors to deal with. I do look at it every so often just to make sure all the lights that should be green ARE green but other than that, it simply occupies some floor space in the basement. BFD.
John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN Beware the lollipop of mediocrity. Lick once and you suck forever.
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Those forklift batteries are so freaking heavy you may as well use them as the mass for the gravitational potential energy storage :)
You could charge the batteries till they were full and then use the lifting on them as the diversion load
ha hah ha
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//

that is (assuming you can drain the last drop out of the battery) 2.4KWhr - a perfectly valid emergency supply I got

and you have it bunded - ie it is in your cellar.
& it is NOT the Heath Robinson brew suggested by the wiki article.
//

Oh yes? There's loads of idiots out there, including govt ministers and advisers and civil servants, who obviously cannot do the simple sums & do not think it is a silly idea. And they are right there in the middle of govt putting up all of our elec bills.
The daft idea has got out that wind energy is 'free' and all you do is put up a fan, plug it into the mains and lie back whilst the cheques roll in. It is perhaps inexhaustable, but is it truly renewable? The expected life of a wind turbine is c.30years. Not very long as electrical generation infrastructure goes. Plus there is a large plug of expensive-energy-consumed concrete under it.
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jim wrote:

24kWh, more than a days worth for most homes, especially if you realise it's an emergency and can cut down on usage to make it last.
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wrote:

Correct. In an experiment, I made it a week and didn't drop below 80% DOD. Now I did cheat and turn on utility power to heat water to shower with but the charger was off and all my vital bus lighting was still on the UPS. Doing without a shower for a week is more than I'm willing to sacrifice for an experiment.
In a real emergency I would probably run the genny every other day to shower and refill my water tank. My stove is electric but I have a Coleman 3 burner stove in my summer (outdoors) kitchen and then there's the stove in the motorhome. (gotta get that well pump on the UPS!) Otherwise, a week would be no problem at all. Especially in the winter when I can roll my chest freezers outside. I mounted them on wheels for that purpose.
John
-- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN Vegetarian - Indian word for "poor hunter".
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What brand/model chest freezers you have?
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On Mon, 08 Dec 2008 21:16:12 -0600, snipped-for-privacy@privacy.net wrote:

Yard sale specials. Why, what features are you interested in? My wheels consist of 1 and 2 (for the larger freezer) furniture movers, those wooden platforms with 4 casters mounted on the corners. I'd need something better if the surface was at all rough but this does fine on concrete.
John
-- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN You can't turn [MS] shovelware into reliable software by patching it a whole lot. -Marcus Ranum
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