Originally Posted by
tomgoodman
As a demonstration project, the TVA built a large reservoir in the mountains, connected to the valley below by a massive water pipe. During periods of low demand, they would use surplus electricity to pump water up there, then let it out to run a turbine during peak demand. Don't know how successful this has been, or whether they will ever recover the cost to build it.
A similar project was proposed in California not too long ago, but for the most part all storage is in coal and nuclear fuel. Hydro plants can be a boon to those areas with a suitable terrain and water supply.