We develop disruptive electricity storage technology that transforms intermittent renewable energy into fully dispatchable electricity. Our low-cost solution allows energy use anytime, regardless of weather, rivalling fossil fuels and nuclear power. We convert electricity into heat, storing it in molten silicon at 1410°C—cheap, energy-dense, and made from the second most abundant element on Earth. When needed, we convert it back to electricity using thermophotovoltaic (TPV) cells, efficiently harnessing energy whenever it's required, regardless of the sun shining or the wind blowing.