The thermodynamics of energy storage

One of the big problems with any renewable energy source comes in syncing the production with demand. Wind for example produces power when the wind blows. That is not always when the power is needed. Most energy storage mechanisms are expensive and require special materials (batteries, ultracapacitors, etc.). Wikipedia has a good explanation of all the major technologies implemented on the grid today. What about simpler ones? One idea is to compress air and have the thing drive a turbine to generate electricity on the way out. TOD did a total review of the thermodynamics of that reaction yesterday. Doesn’t look good, but in an environment where the electricity is going to go waste anyway (say extra wind power), then efficiency is less important. Today pumped hydro storage is used widely to load balance hydro dams.

what about a consumer version of this???