Capability study of dry gravity energy storage

The increasing penetration of intermittent renewable energy sources has renewed interest in energy storage methods and technologies. This paper describes a gravitational potential energy storage method. A review of current storage methods that make use of the principle of gravitational potential energy is done, with a comparison given in terms of power, energy rating and round trip efficiency. One of these gravitational energy storage methods, involving moving a solid mass vertically up and down, is further analysed in terms of energy storage capacity, energy and power density and the levelised cost of storage. Two different hoisting methods are discussed, the first of which is the traditional drum winder hoist and the second is a proposed, multi-piston hoist based on the use of linear electric machines. The two hoist methods produce storage systems with distinctly different properties and storage applications.