Seemingly taking a page out of carbon sequestration's playbook, a coalition of local facilities in Iowa are working out a scheme to store surplus wind energy by placing it underground. The idea being to keep it safely locked up when demand is low so it can then be uncorked at a later date when demand - and, consequently, prices - are higher.
The utilities plan on building a system that will rely on a gigantic air compressor (as seen in the diagram) to pump air into porous layers of sandstone. In essence, the layers of sandstone will act as a giant balloon, allowing for wind energy to be stored until a later time when demand is high - at which point the flow will be reversed, unleashing a large amount of air into a natural gas-fired turbine. This 268-MW compressed air energy storage (CAES) system is on track to be completed by 2011.As we reported on a few months ago, TXU Energy in West Texas is also hard at work building a large installation of windmills - with a 3,000-MW capacity - that will be connected to a similar CAES system to pump air into underground salt domes. This trend towards storing wind energy is unlikely to peter out any time soon: according to the Electric Power Research Institute, over 85% of the U.S. is characterized by subterranean features that would allow for such a system to be implemented.
Via ::BusinessWeek: Catching The Wind In A Bottle (news website), ::Ecotality Life: Midwest Utilities To Store Surplus Wind Energy Underground (blog), ::Engadget: Excess wind energy to be stored underground for future use (blog)