A nice, short comparison of the cost of electricity storage with pumped hydropower and batteries.
Using pumped hydro to store electricity costs less than $100 per kilowatt-hour and is highly efficient, Chu told his energy advisory board during a recent meeting. By contrast, he said, using sodium ion flow batteries — another option for storing large amounts of power — would cost $400 per kWh and have less than 1 percent of pumped hydro’s capacity.
Of course, you need to have a river with a likely reservoir location to have any significant quantity of pumped storage, making the article’s reference to Texas a bit ironic.
For those unfamiliar with the concept, here’s a nice diagram of pumped storage from Consumers Energy: