[thackney]

semiburied large water tanks can be used for pumped storage

Pumped storage is used in some place. A small pumped storage takes a lakes/river with significant head difference. There is no way tanks could be built large enough to have any economical application.

[Pontiac]

Interesting sites for pumped storage. First site is a slide show (large file).

http://www.asiapacificpartnership.org/PowerGenTF/AugustEEV/Seneca%20Pumped%20Storage%20Generation%20Plant.ppt

http://www.pseg.com/companies/fossil/plants/yardscreek.jsp