More hopefully we may be on the cusp of a dam building renaissance. Pumped storage, no need to have a high up water source. Soon wind farms may be built accompanied with a dam and lake to store their output and release it when needed.
Pumped storage needs far too much space to be significant as an energy storage solution for renewables. Sure it is useful, but the amount of space needed to hold the lakes to supply the US through the worst week of the typical years would cover most of the mid-west.
