Compressed Air Energy Storage to Store Wind Energy (Score 2, Interesting)

Compressed air is another means of storing wind energy that is getting looked at again. The CAES schemes need large geological structures such as salt mines or depleted gas fields, but there are quite a lot of viable structures in places like Texas and Ontario where there is also interest in wind energy. It is not economical on a small scale since a large part of the compression cost is independent of the reservoir size.

According to the US Department of Energy "nearly two-thirds of the natural gas in a conventional power plant is consumed by a typical natural gas turbine because the gas is used to drive the machine's compressor. In contrast, a compressed-air storage plant uses low-cost heated compressed air to power the turbines and create off-peak electricity, conserving some natural gas."

In the last 20 years only two facilities have ever been built - a 110-megawatt plant in Alabama and a 290-megawatt plant in Germany. Iowa is building a new plant "expected to cost $200 million and operate by 2011 with the capacity to store 200 megawatts of power, enough for several days. Both the Iowa and Alabama installations can draw air to make power within 15 minutes and make a gas turbine roughly 40 percent more efficient. "

http://www.eere.energy.gov/de/compressed_air.html
http://arstechnica.com/news.ars/post/20081224-full-of-powerful-wind-bury-it-in-the-ground-for-later.html
http://www.thestar.com/business/article/553702
http://www.isepa.com/index.asp Iowa Stored Energy Park
http://news.zdnet.com/2100-9595_22-178929.html