Scenarios for a transition to a hydrogen society are constructed for Denmark. The physical basis for the scenarios is the exploitation of renewable energy resources already in progress in Denmark. Hydrogen is proposed as a convenient energy carrier due to its versatility in use, transmission and as an energy storage medium. Two main scenarios are constructed, differing in the degree of decentralisation of energy production and management: one resembles the current system with centralised facilities and commercial management, the other being based upon a projected scale-independent cost structure of energy producing and handling equipment, that will allow extreme decentralisation of the physical energy conversion system, possibly accompanied by a similar decentralisation of ownership and control. The simulation studies show that both scenarios are technically feasible, and that the storage problems arising from the mismatch between demand and intermittent sources can be solved in both a centralised and a decentralised fashion. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.