To Store and Convert examines the prospects for using energy storage to compensate for the intermittency of wind and solar energy. It opens with a visit to a large battery storage facility. Batteries are then compared to other forms of energy that can be converted back to electricity: pump storage, compressed air, gravitational, thermal, hydrogen, and ammonia storage. Conclusions are that storage will be useful for compensating for most minute-by-minute and hour-by hour variations in wind and solar generation. No known method, however, can store enough energy to compensate economically for lack of nighttime solar generation or for periods of calm winds and overcast skies lasting hours or longer.