Hi, this is my first thread, inspired strangely enough by discussing energy storage on the moon.


Wind power is pretty cheap. In general it appears to be cheaper than nuclear power and if it continues to drop in price it could become as cheap as coal power without the massive environmental drawbacks that come with coal. One problem is that it is intermittent. Now the average electricity grid can handle a decent amount of wind power without a problem. A grid can get perhaps 20% of its power from wind before dealing with its intermittency becomes difficult. Suggestions have been made for getting around this problem, building wind farms in widely separated areas, teaming it with solar power and so on. One solution is to store excess energy for later use when it is needed. I have a perhaps silly idea for energy storage, which I’m sure other people have had before me but perhaps rejected on account of being smarter than I.

Wind generators are mounted on top of tall pylons. These pylons are built very strong to resist gales and storms. During periods of excess energy production it might be possible to winch a heavy weight up to the top of the pylon and then in periods of low wind use its potential energy to turn the windturbine. A ten ton weight winched up to 50m could store energy that could potentially generate up to 450 kilowatt-hours of electricity, which might be an hour's worth of average power from a wind turbine. The weights would have to be lowered during storms for safety reasons.

We already use this type of energy storage system when hydroelectric systems pump water back up to a higher level, which is cheaper to do than building a system to lug weights up to the top of a windmill. However, it just may be possible that this system might be practical for an isolated wind power system that isn't connected to the grid. Perhaps one powering a remote village, farm or mining operation.

So, do you think there is any merit to this idea or is it likely to be too impractical?

I think that it would place too much stress on the tower.
They would also limited as to how much energy they can store.

My idea, that I put on a thread months ago, is to have stations that electrolyze water(to produce hydrogen gas)in times of excess wind generated electricity and then when there is no wind the hydrogen can be burned to drive turbines. In this way the only limit to the amount of energy that can be stored is the capacity of the hydrogen tanks.

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Good points, however it is simpler than creating and burning hydrogen and much more energy efficent as as you lose a lot of energy splitting water which might be 60% efficient and buring hydrogen in a generator will generally at best be 45% efficent, so you will only get back about 27% or less of the energy you put into it, while storing energy in a suspended weight could return perhaps 80% of the energy put into it. The high volume of hydrogen and its small molecular size also makes it difficult to store.

Hey! This is the best kook idea I've ever read. (The fact that it
was proposed on the Internet is the only thing making it a "kook"
idea ) I suspect the idea has been around for a while, but in
any case it sounds definitely worth exploring further.

-- Jeff, in Minneapolis

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If you winch a weight up, you can certainly recover energy from it. Imagine what I'm about to recover from this one....

Seriously, while storage is a good (but not new) idea, I'm not sure lifting a weight is the best way to go about it. Most wind generators are not all that big, they just use a lot of them. Might be interesting to experiment with it though.

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Well, a lot of wind turbines today are being mounted on pylons over 85m in height and have rotor diameters of over 70m so that's sort of big. However, I've never heard of gravitational potential energy being stored with anything except water, which makes me think that my idea may not be practical, but since it uses the windturbine's generator and a pylon that has to be built strong enough to resist storms anyway, just maybe it will be cheap enough to be practical.

Just wondering (because I didn't see the other thread) how you would source the energy to burn the hydrogen when the wind doesn't blow (nuclear, coal burning?), and if you would end up with a bigger usage of energy to produce the electricity?

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I don't understand.





The wind generated electricity would be fed into the national grid where hydrogen generators would be situated to generate and compress( to liquid)hydrogen. It would then be burnt conventionally to driver dynamos to generate electricity at low wind times.

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The storage idea is nothing really new. In fact I did a study/report for NASA about three years ago on this very topic (with other ideas as well). A better method is the use of flywheel energy storage.


While you are correct in stating that wind power does not have the "massive environmental drawbacks that come with coal," wind power does require a lot of land use and that creates it own environmental problems.

I think roads use more land.

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The tower is actually one of the most expensive parts of a wind turbine; much of the innovation that has made modern wind turbines economical has been in reducing the weight and cost of the tower itself. Making it strong enough to support a heavy weight would likely make the whole thing too expensive to be viable.

Somewhat ironically, some larger turbines do have a weight on a cable--for the service elevator.

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Yes reading Frog March answer i had the same reaction about efficiency of electrolizing water. Your idea sound great , it can be improved IMO : Why not builds pecific tower or device to store wind energy from more than one wind turbine , for an entire farm of turbine in fact. Cost are mutualized with this solution and you can build simple tower optimized for storing energy and you not impact the wind tower.

That sounds much more do-able; in fact, if you make use of local terrain (ie the mountain that the turbines are on in some regions) you could probably do it pretty cheaply. I'll bet there is already a patent...

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Ronald your scheme is stimulating : i have an other idea : the tower has not to be a tower but can be a well ! Energy is stored underground !

instead of a ten tons weight hanging on the mast of poor wind turbine , imagine 2 X 100 tons weights sliding up and down in their well like an elevator. When one is up it is ready to product energy for the grid . When the other is down it is ready to be lifted again and store energy from the wind farm. So you dont connect directly the wind turbines to the grid , you connect your mechanical storage device. And the landscape is not impaired att all .

Next step put the wind mill underground also !!!!!
Hum excess of enthousiasm maybe !

Heh, actually, if we optimize the system completely I think we wind up with a hydroelectric pumped-storage system like we already have all over the country.

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well that would be easier for turbines at sea, there would be no need to dig the hole.

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Well yes and no. The footprint of a wid turbine is small, but you have to clear a lot of land for it to be viable. ie no trees or obstructions. Once you put a wind turbine farm in, the land can not be used for much, except open range cattle.

The other problem with wind power is that mountains are one area that works really well. In Texas the best places, are two mountainous national parks and several mountainous state parks. The panhandle (northwest part) is pretty good too, but again some of that land (but not a whole lot) is either federal or state lands.

Of course people have seen the use of weights as energy storage before, it was quite popular in clocks, you know. I never did see a clock with flywheel energy storage though, perhaps it was not as practical to store that much energy in a wheel that fitted inside the clock.

The problem with them not taking anymore energy when fully raised is compairable to a saturated flywheel. A drained well and a stopped wheel is similar. You would need to make a big silo of some kind for the weight and safely deccelerate it at the bottom, while wheels need you to use strong materials and build what amounts to a bunker in case the wheel were to fragment.

The question is, could one make well energy store systems, that was either cheaper per unit of energy or that could store more energy than is practical with a wheel.

Underground silos with the weights might be a better solution than using the towers themselves, though. You probably would build wheel storage underground too.

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My point is this: To power an industrialized country like the US or the UK by wind turbines you need to use a lot of land which basically turns that land into land that can't be used for much else. That will create new environmental problems. Though I doubt that it will be as bad as coal or any other fossil fuel, but it still is a problem.

Well jrkeller has pointed out that flywheels are a better way to store energy. I thought my low tech suggestion might be a little cheaper, but obviously this idea has already been looked into.

As for wind power needing a lot of land, this doesn't seem to be the case. In Europe they don't seem to have a problem using the land under them for crops and the structures themselves only take up 1% of the land. In addition windturbines can be put out at sea, taking up no land at all.

In fact, windturbines generating the same average power as a nuclear plant can take up less actual groundspace than a nuclear plant.

Sorry, I realise I didn't ask my question very clearly. What I'm asking is by what method will you be burning the hydrogen? I don't know much about burning hydrogen (aside from lighting a match), so I don't know what the "conventional" means are.
Does the burning of hydrogen rely on a source of electricity, for instance?
If so, how is that electricity sourced?
And does the energy that is spent compressing then burning the hydrogen result in a greater rise in entropy than if the same amount of electricity was produced by, say, nuclear power?

I don't mean for my questions to sound like an interrogation - I'm actually very interested and just ask in order to learn more.

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Well I'll jump in and mention that you can burn hydrogen to produce electricity in the same way that natural gas can be burnt to produce electricity, the only real difference being that hydrogen has more volume per unit of energy so more cubic meters of gas will have to be burnt to generate the same amount of electricity. I imagine this is what's meant by "conventional."

As for the rise in entropy part, since gas generators are in general more efficent than nuclear reactors at turning heat into electricity, I imagine nuclear power would cause a greater increase in entropy. But I don't think that looking at entropy is all that helpful when talking about power generation. Generally costs and environmental effects are what people look at.

The other good thing about hydrogen power is that it does not produce C02.

I just visited these about a month ago.

If you take CO₂ from the atmosphere and Water from some handy source, you can make Methanol as fuel without impacting the net Carbon in the atmosphere. This is really only usable as a means to store power generated some other way, but it is denser than Hydrogen, and just as green.

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10 tons (10,000 kg) raised 50m is 4.9 x 10^6 J

A kW-hr is 10^3 J/s x 3600s = 3.6 x 10^6 J

It looks like you are underestimating the mass you need to lift (or the height) by a few orders of magnitude.

Water works for this purpose because you can move smaller amounts at a time, raise it higher, and store it in a more stable environment.

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I am intrigued by the flywheel concept as a form of energy storage, jrkeller. Would it be possible for you to give us some information about the efficiency of this method? It may be the case that each wind turbine could be surrounded by flywheel storage systems without much extra impact on the local environment.

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Very well done . I had an afterthought adn did the same computation but you beat me posting it .
End of the show

Well that explains why flywheels are superior. Time for me to go back to maths class I think. Thanks for pointing this out swansont. I think I've just learned not to post anything without quadruple checking the maths and doing some thought experiments to ensure I'm not orders of magnitude off, you know, like, "If this is true, is it physically possible for me to lift a bottle of softdrink above my head?"

I feel so silly. Situation normal.

Sorry everyone. I appolgize for my incompotance.