CNet.com:

A start-up says it’s devised a system to produce electricity from wind turbines even when there is no wind, taking on the major challenge of storing wind-generated power.

[General Compression’s] plan calls for sending highly compressed air down the tower and into underground storage, such as caves or depleted gas wells, or through pipelines. The pressurized air can be released when needed to power an electricity generator, even if wind is not spinning the turbine’s blades.