Comment Re:flywheel (Score 4, Informative) 245
There's a much easier solution, already in operation - pumped hydro power plants. They're hydro electric power stations, but when there's a surplus of supply, they pump water up into their reservoir. When peaks of power production are needed, they generate. They can be turned on at a moments notice (all it takes is opening a sluice, and dropping the water), and can store vast amounts of energy.