As the electric grid is increasingly powered by intermittent renewable sources, energy storage will become increasingly important to allow the electric grid to stable regulated power. Simultaneously, electrification of heating will increase demands on the electric grid and potentially lead to peak demands on cold nights. Unlike current battery technologies, thermal energy storage is low cost, does not degrade over time, and can be integrated into buildings in a wide variety of ways. With appropriate time-of-use rates or demand curtailment contracts, buildings can be managed profitably to use excess renewable energy when it is available on the grid and curtail demand when it is not. In this way buildings at all scales can be a large part of the solution that enables an economy powered entirely by renewable energy.