as i understand it, the process is about on par with energy storage in load acid batteries. most times, the cost to store electricity in lead acid batteries over the life of the batteries on a per kw-hr basis exceeds the value of the electricity.
This is supposed to be more efficient because the turbines themselves don't produce electricity, instead all they are are wind-powered air pumps. The air proceeds through tubes/ducts to a central facility where a turbine designed to extract power from pressurized air actually produces the electricity.
So you're not wasting electricity pumping the air in the first place. Maintenance should be pretty easy as well.
No idea if the system can compete with traditional wind turbines though, it might have use as a green 'peaker plant'. Leave the central turbine off/at minimal production most of the time while you build up pressure, then turn on during peaks.
