ENERGY STORAGE AND SUPPLY TO ELECTRICAL GRID

An energy storage and supply system for supplementing a mains grid includes a photovoltaic array to generate electricity, a pumped hydraulic energy store and a battery energy storage system (BESS). The pumped hydraulic energy store and the BESS are connected to a common DC bus, which in turn is connected to an inverter to supply power to the mains grid. If the local area is disconnected from the mains grid, the arrangement allows the BESS to instantaneously supply local power while the pumped hydraulic energy store is brought online.