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There are a number of pump-solar energy storage plants already in use, including some in the US. See http://en.m.wikipedia.org/wiki/Pumped-storage_hydroelectrici... for details.

Its not as sexy as new battery tech, but it works really well and is a very attractive option in some locations.

Outside pump solar, California is planning 1.3 GW storage by 2020. http://en.m.wikipedia.org/wiki/United_States_Department_of_E... will show you the status of projects.

http://en.m.wikipedia.org/wiki/List_of_energy_storage_projec... is an interesting list of projects, including battery based, but also things like flywheels.