Midwest Utilities To Store Surplus Wind Energy Underground

Just a thought and a question. Wouldn't it be more efficient for each windmill to directly pump compressed air instead of having to put huge generators up there? Less voltage dop also? The piping could be integral to the storage and travel to substations where it would then be converted to electrical power. Am I way off on this one?

What you describe has similarities to what is planned for the air-powered cars in France, to have compressed air filling stations that are supplied by (nearby) wind turbines.

There are also proposals to build industrial parks with a centralized compressed air supply (to run all the air tools etc.), generated and stored using off-peak, alternative, or locally co-generated power.

But in this case, they need to transmit surplus energy (regardless of source) to one specific (geologically favourable) site, and store it as comp. air, where it is used to "supercharge" the gas turbines, and the electrical transmission infrastructure is already there.

The cost of building and maintaining a large area (or long distance) comp. air infrastructure is quite likely prohibitive.

Most importantly, converting comp. air directly to electricity is not very efficient. It's only marginally viable to use comp. air to power a commuter vehicle (supposedly) because its storage can be integrated into the frame structure, and drives a next-gen (very hush hush) air motor.

On a lighter note, can you imagine if this underground air storage sprung a leak? Think World's Largest Whoopie Cushion!

Now the French air car is as practical as riding a badger to work, but with poorer mileage (it really is that bad, look at their website for yourself, and my previous assessments listed in other posts). However, compressed air as a storage method, especially in such a large and radical application as this could be economically viable and sounder than many of the alternatives (such as huge battery banks). I say "potentially promising" and will have to keep an eye on it as it progresses.

Good "thinking outside the box" engineering. The question is, is it viable from a geological point of view.

I'm pretty sure it would take a large pack of badgers & a cart to get my ass to work. Wouldn't elevating or compressing some liquid be more efficent?

In response to Jack, you'll note I wrote "supposedly" in regards to the viability of the air car business. Let's let the French sort that out. But it has its appeal from the standpoint of no petroleum, no CO2, no pollutants, no ravaged rainforests, and no batteries to recycle. And no badgers.

I agree that this storage scheme and application is clever. I think the whole point is to take advantage of an existing geological formation, and is not unlike the plans to sequester CO2 in old wells, or using CO2 to pressurize old wells in order to extract more oil.

Garth, they already use surplus power to pump water up to the headponds of hydroelectric dams. Not sure how the efficiency compares, but once the headponds are all topped up, this is hopefully another viable option.

It is a cleaver thought to use an existing formation, I have yet to see pnumatics that are anywhere close to efficent. Storing potential that would other wise be wasted, is something to be explored. Things that are silly when oil is $20/bbl, look really smart @ $80/bbl.