The Grid Needs Storage, Not Every Storage Idea

A new long-range analysis of grid storage looks out to the year 2100 and concludes the power grid will need a lot of batteries and pumped hydro (a system that stores energy by pumping water uphill, then releasing it through turbines later), but far less exotic storage than some forecasts assume. Battery costs keep falling fast, and batteries are increasingly being built for longer stretches of storage, not just the two-to-four-hour systems that used to be standard. Britain has approved battery projects designed to store power for eight to eighteen hours, and China's battery fleet has grown enormously, though most of those batteries still store only around two hours' worth of power.

The analysis argues that grids will need less dedicated battery and pumped-hydro storage than once thought because other tools can do part of the job more cheaply. These include long-distance power lines that move electricity between regions with different weather, shifting flexible demand (like EV charging or water heating) to times when power is cheap and plentiful, and storing heat itself — in hot water tanks, underground boreholes, or district heating systems — rather than converting it back and forth from electricity. For homeowners with heat pumps, this last point matters: heat storage systems can help smooth out the cost and strain of winter power demand, since heat pumps draw more electricity on the coldest evenings.

For newer storage ideas like compressed air, liquid air, or iron-air batteries, the analysis says they still need to prove themselves with real, working projects before they deserve a bigger share of future grid plans.