Pumped hydro has nowhere near the capacity necessary to consider it a complete solution to long-term energy storage[1]. Tesla has shown that batteries can be v

Pumped hydro has nowhere near the capacity necessary to consider it a complete solution to long-term energy storage[1]. Tesla has shown that batteries can be viable in some cases (e.g., passenger vehicles), but that is but a tiny fraction of the cases where the versatility, mobility, and energy density of fossil fuels are used. Virtually all other long-haul transport (passenger flight and cargo hauling for example) uses them exclusively for starters. Nothing about transitioning away from fossil fuels is "simple", and it's likely to involve a patchwork of partial solutions[2]. [1]: http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-storage/ http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-stor... [2]: http://physics.ucsd.edu/do-the-math/2012/02/the-alternative-energy-matrix/ http://physics.ucsd.edu/do-the-math/2012/02/the-alternative-...