In this paper we assess the feasibility of various future energy production pathways for hydrogen. We argue that neither nuclear energy, nor coal gasification with carbon collection and storage can provide sufficient climate-neutral energy to be probable routes to a hydrogen future. Their contributions are likely to be too little and too late to be of much help. Hydroelectricity, geothermal and biomass energy can all provide base-load power, but even combined have limited potential, and are not always climate-neutral in operation. On the other hand, the high-potential renewable energy (RE) sources, particularly wind and direct solar energy, are intermittent. Further, wind resources are poorly matched to the existing distribution of world population. Wind power's high potential compared with present electricity demand, high return on energy invested, intermittency, and mismatch with load centres all favour hydrogen conversion and transmission to load centres. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.