[Uncledave]

Compressing air creates a lot of wasted energy lost to heat. Pumped hydro (pumping uphill to a reservoir feeding a hydro power plant) doesn't not have near the losses of compressed air.

Of course, you have to be near a dam to make use of this.

One neat thing about the compressed air storage option is that the wind turbines can be designed much more simply, inexpensively, and easier to maintain. You just run the compressor right off the drive shaft - no need to deal with anything electrical, and all the gearing is much simpler.

These guys are out in front of it: http://www.generalcompression.com/about-us/

[Uncledave]

Meant to include you on #16

[thackney]

You would need to be near a salt dome to store a significant amount of compressed air. The most impressive thing I see done at your link is raise money from investors.