Buoyancy energy storage technology : an energy storage solution for islands, coastal regions, offshore wind power and hydrogen compression

Abstract

The world is undergoing a substantial energy transition with an increasing share of intermittent sources of energy on the grid such as wind and solar. These variable renewable energy sources require an energy storage solution to allow a smooth integration of these sources. Batteries can provide short-term storage solutions. However, there is still a need for technologies that can provide weekly energy storage at locations without potential for pumped hydro storage. This paper presents innovative solutions for energy storage based on “buoyancy energy storage” in the deep ocean. The ocean has large depths where potential energy can be stored in gravitational based energy storage systems. The deeper the system, the greater the amount of stored energy. The cost of Buoyancy Energy Storage Technology (BEST) is estimated to vary from 50 to 100 USD/kWh of stored electric energy and 4,000 to 8,000 USD/kW of installed capacity. BES could be a feasible option to complement batteries, providing weekly storage cycles. As well as from storing energy, the system can also be used to compress hydrogen efficiently.