The realisation of the hydrogen economy has been the HolyGrail of energy research in the 21st century (Rifkin, 2002). The generation of hydrogen from wind or photovoltaic-poweredelectrolysis will provide a way to buffer the variations in the secarbon-free energy sources and produce a clean fuel for transportation. The infrastructure will be developed centrally to begin with and may then be deployed in a dispersed fashion as costs are driven down. The initial deployment needs a grid capable of pooling both energy demand and supply. In the longer term, this infrastructure may no longer be needed as smaller-scale equipment becomes viable. But, as with any emerging technology,realising economies of scale and maximising efficiency and the use of existing infrastructure will be preconditions for commercial success.The outlook for commercial success in 2050 and beyond depends on the resolution of many technical problems. The se include serious safety and technical concerns with the storage andtransportation of hydrogen.