A system to "store" energy by producing hydrogen from wind powered electrolysis of water has been patented by a small north Wales company. Declan Pritchard from Anglesey Wind and Energy claims that his pollution free system could overcome the limits imposed on wind energy's penetration of electricity networks. Electrolysis of water, powered by wind, would create hydrogen and oxygen which, when used with a fuel cell, would produce steam and electricity. The steam is recycled back to the electrolysis phase after first passing through a heat exchanger or turbine to capture the thermal energy. Pritchard says nearly 5 MWh of electricity are needed to make 1000 cubic metres of hydrogen gas. When passed through a fuel cell, this yields 1 MWh as electricity and 1 MWh as heat, giving an overall storage efficiency of 40%. Pritchard is designing a grid connected demonstration wind project to switch output between the grid and hydrogen production in response to the immediate price paid for electricity exported to the grid. He is now seeking partners to develop a demonstration project, ideally for a hospital application where most of the products-electricity, heat and oxygen-are needed.