The Last Mile of Renewable Energy Storage Is Unsolved

Solar and wind are now the cheapest energy sources ever. But they only work when the sun shines and wind blows. Long-duration energy storage (100+ hours) remains unsolved and is the key bottleneck to a clean grid.

Renewable energy has won the cost war. Solar and wind are now the cheapest sources of electricity in most of the world. But there's a fundamental problem: they're intermittent.