A gravity battery is a type of electrical storage device that stores gravitational energy, the energy stored in an object resulting from a change in height due to gravity, also called potential energy. A gravity battery works by using excess energy from the grid to raise a mass to generate gravitational potential energy, which is then dropped to convert potential energy into electricity through an electric generator. Energy generated from a gravity battery is a form of sustainable energy. One form of a gravity battery is one that releases a mass, such as a block of concrete, to generate electricity. The most common gravity battery is used in pumped-storage hydroelectricity, where water is pumped to higher elevations to store energy and released through water turbines to generate electricity.
The earliest form of a device that used gravity to power mechanical movement was the pendulum clock, invented in 1656 by Christiaan Huygens. The clock was powered by the force of gravity using an escapement mechanism, that made a pendulum move back and forth. Since then, gravity batteries have advanced into systems that can harness the power of gravity and turn it into electricity for large scale energy storage.