The role of hydrogen in a global sustainable energy strategy

This paper reviews the role envisaged for hydrogen energy within the context of global and national 'sustainable' energy strategies, that is, strategies seeking to address climate change imperatives and guarantee energy security. The focus is on studies conducted over the past 5 years. Reviews are provided in turn of the International Energy Agency's World Energy Outlook 2012; the 2012 Intergovernmental Panel on Climate Change's special report on Renewable Energy Sources and Climate Change Mitigation; one of the first spatially disaggregated energy-economic modeling studies of the role of hydrogen in a national economy using the MARKAL model; and a recent study into whether the world can rely just on energy efficiency and renewable energy alone. Some general guidelines for integrating hydrogen into sustainable energy futures are proposed. Key challenges facing hydrogen energy and technologies are identified and ways to overcome these barriers are suggested. Finally, some positive recent developments indicating that hydrogen energy might be on the verge of a comeback are described. (C) 2014 John Wiley & Sons, Ltd.