This review makes the case for cheaper and more efficient water electrolysis technology. In particular, the potential advantages of zero gap, alkaline water electrolysers based on hydroxide ion conducting membranes are highlighted. Following a brief introduction into the thermodynamics and kinetics of water electrolysis, recent developments in oxygen evolving anodes, hydrogen evolving cathodes and hydroxide transporting membranes appropriate to such technology are reviewed. ► The need for improved water electrolysis technology if it is to contribute to a green energy economy. ► Developments in electrocatalysts for zero gap alkaline water electrolysers. ► Developments in hydroxide transporting membranes for such cells.