US Patent 10138875 Gravity field energy storage and recovery system

Device for storing energy using a physical object, such as a mass of greater than 10,000 kg, or buoyant object, floating in fluid, capable of displacing 10,000 kg. A mass is repositioned to greater altitude in a gravitational field to a position of higher potential energy. A buoyant object is forcibly submerged into a fluid, displacing greater than 10,000 kg of fluid, to a position of higher potential energy. The stored potential energy may be recovered with extremely low loss regardless of the state of charge of the system, or length of time of the storage.