We are at the beginning of a global energy transformation of a scale not seen in generations. A future low-cost, low-carbon electric grid, serving a world that electrifies everything, is within our reach.

The last remaining gap is breaking the link between electricity supply and demand. The lowest-cost, most sustainable sources of energy today come from intermittent renewable generation; but our homes, businesses and industries need electricity at the flick of a switch.

That gap can be closed by energy storage: Devices that store electricity when it is plentiful, then provide power back to the grid when it is needed. Solutions, including ones using lithium-ion batteries, are being deployed in massive numbers to start filling this gap. But so far, none of those solutions have proven the ability to deliver power any time, anywhere, over decades of service: The level of reliability we’ve come to expect, and that the future grid will need.

This is the biggest ...