Slashdot Mirror
Underground 'Wind Mines' Could Keep Datacenters Powered
Nerval's Lobster writes "Major IT vendors have been including custom-built wind- and solar-power farms in their datacenter construction plans. But while wind and solar power may be clean, they're often unreliable, especially by the standards of datacenters that need a way to keep operating through any unexpected surges or drops in power. How about saving the wind that generates the power? That might work, according to researchers at the federal Bonneville Power Administration (BPA), and U.S. Department of Energy's Pacific Northwest National Laboratory. A study published in February (PDF) outlined the potential benefit of pumping pressurized air into caverns deep underground as a way to store wind energy, then letting it out whenever demand spikes, or the wind drops, and the above-ground facilities need help spinning enough turbines to keep power levels steady. The technique, called Compressed Air Energy Storage (CAES) isn't new: existing CAES plants in Alabama and Huntorf, Germany (built in 1991 and 1978, respectively) store compressed air in underground salt caverns hollowed out by solution mining (pumping salt-saturated water out of concentrations of salt buried far underground and replacing it with fresh water). But implementing such a technique for datacenters might take a little work. The BPA and the Pacific Northwest National Laboratory have already identified, and are evaluating, sites in the Pacific Northwest that would be suitable for CAES underground reservoirs; the first, which could be located in Washington's Columbia Hills could—via existing CAES technology—store enough compressed air to generate a steady 207MW for 40 days of continuous usage, ultimately delivering 400 additional hours without adding any compressed air."
burritos. Then we have them run over to the turbines and release any stored energy. The department of energy calls it Flatulence Assisted Regeneration Technology. Doesn't work quite as well as pumping the earth's crust up like a baloon though.
Wouldn't it take a buttload more power to move the air down, and then back up, than it would generate?
I think it presumes excess power during some periods. High winds, excess hydro power, what ever.
They do this at Grand Coulee Dam already by pumping water up-hill to an additional reservoir in periods of excess runoff when they would otherwise have to open the spillways just to get rid of the excess.
Pumping water uphill is probably far more efficient than compressing air.
Sig Battery depleted. Reverting to safe mode.
If you use an air-water mixture, this can be done quite efficiently: http://lightsailenergy.com/
Quite many buttloads, I'd presume.
Fortunately a buttload of pressurized air doesn't actually have much force behind it.
Source: personal experience.
Does this rag smell like chloroform to you?
Wouldn't it take a buttload more power to move the air down, and then back up, than it would generate?
Any flavor of energy storage is going to introduce some sort of conversion losses: battery banks aren't 100% efficient to charge or discharge, flywheels suffer from friction losses, pumped-water hydro suffers from inefficiency in the pumping uphill and the conversion to electricity downhill backup generators suffer from the fact that small heat engines generally get lousy efficiency compared to big ones(and need to be kept supplied with diesel, which doesn't help you 'green' cred).
The advantage to pressurised air is that(in geologically suitable locations) you can build in fairly large amounts of storage without anything obtrusive on the surface, and at comparatively low cost(compared to buying and keeping fresh huge banks of batteries, say).
sure. not to mention the atrocious efficiency of wind power. Just pump water to a reservoir instead and let it out when you need it.
I think that the article is trying to be clever, but missing an important point in doing so. Energy is generated from the compressed air using a more conventional turbine/generator setup... not a wind farm. This system is just an ENORMOUS UPS.
Using compressed air as a storage medium has a number of problems:
1) Low energy density. Air is very compressible. While that's what makes it usable as power storage in the first place, the amount of energy that can be saved in a gallon-sized container as compressed air pales next to a gallon of gasoline.
2) Power loss through thermal contraction.. When you compress air, it heats up. As that heat energy escapes, it effectively takes away a good chunk of the energy you consumed compressing it in the first place. Once the compressed air has cooled, the effective pressure drops. The more air you compress into the same space (See Energy Density above) the worse this effect is.
3) Power loss through leakage Even when available, caves are terrible places to store compressed air. Even if you seal the cave somehow, you then have to deal with seismic shifting, creating leaks and causing your beautiful, N-redundant power source to leak into an underwater stream bed. Lastly, even when sealed properly, air will *still* leak out. Ever wonder why your bike/car tires need to be aired up every so often even when they *aren't leaking?
Air molecules are wily little critters
4) turbine inefficiency The higher the pressure of compressed air, the more the above problems manifest themselves. However, the lower the pressure of compressed air, the less efficient it is to convert the compressed air back to electricity!
Good solutions address the multiple facets of the problem. For example, much of the cost of running a data center is spent on cooling. It might be preferable to store "coolth" in a stone or liquid cooling chamber under the facility than to try to store compressed air. Compressed air can be turned into electricity, which is more flexible, but is also more lossy for the reasons listed above. A combination of technologies will be needed to provide the best answer for redundancy and efficiency.
I have no problem with your religion until you decide it's reason to deprive others of the truth.
The lost GDP in Salmon exports outweighs the Power exports in Washington State: Grand Coulee's primarily provides power to the US Government facilities, not anyone in Washington State. It also provides power to Arizona. People buy power from Bonneville Power in Washington State. The return of proper salmon runs will currently add > $4 Billion in GDP.