Ancillary services like frequency stabilization are the highest ROI application of batteries in the grid and nothing to sneeze at. Without batteries, transmissi

Ancillary services like frequency stabilization are the highest ROI application of batteries in the grid and nothing to sneeze at. Without batteries, transmission and especially distribution need to be sized to the highest momentary spikes in demand, and given the long lead time and high costs to upgrade these facilities, batteries are a great solution. They can respond instantly and solve the problem at a very low cost. As for storing power overnight, batteries are on a similar manufacturing learning curve* as photovoltaic, albeit a few years behind. Most people thought PV could never be cost effective, until suddenly it was the cheapest. Batteries too will surprise the doubters. It's just a matter of time before batteries are more cost-effective than pumped hydro. *Moore's law-style cost reductions were first observed in airplane manufacturing in 1936. Cost of manufacturing decreases with the volume produced: http://www.uvm.edu/~pdodds/research/papers/others/1936/wright1936a.pdf http://www.uvm.edu/~pdodds/research/papers/others/1936/wrigh...