A 40-foot trailer loaded with 25 tons of liquid metals may be the solution to the renewable-energy industry’s biggest challenge: making sure electricity is available whenever it’s needed.

A Boston-area startup founded by MIT researchers is working to turn this new concept into a commercially viable product, liquid-metal batteries that will store power for less than $500 a kilowatt-hour. That’s less than a third the cost of some current battery technologies.

The technology promises an alternative to the massive pumped-water systems that make up 95 percent of U.S. energy-storage capacity. At that price, developers will be able to build wind and solar projects that can deliver power to the grid anytime, making renewable energy as reliable as natural gas and coal without the greenhouse-gas emissions.

‘If we can get liquid-metal batteries down to $500 a kilowatt-hour, we’ll change the world,” Donald Sadoway, chief scientific adviser at Cambridge, Massachusetts-based Ambri Inc., said in an interview.

Power storage will compensate for the intermittent nature of renewable energy. Batteries can store energy when the wind blows at night, and then send electricity to the grid the next day when it’s needed.
First Prototypes

Ambri won a $250,000 grant Feb. 5 from New York state to develop and test […]