International Journal of Hydrogen Energy 32 (2007) 4611 – 4626 www.elsevier.com/locate/ijhydene Towards a sustainable hydrogen economy:A multi-criteria sustainability appraisal of competing hydrogen futures William McDowall a , Malcolm Eames b, ∗ a Centre for Health and Environment Research, University of British Columbia, Canada b BRESE, Brunel Business School, Brunel University, Uxbridge UB8 3PH, UK Received 5 February 2007; received in revised form 22 June 2007; accepted 22 June 2007 Available online 6 September 2007 Abstract The ‘hydrogen economy’ has the potential to provide a sustainable and secure energy system, and there is a wide and growing literature promoting and exploring different possible hydrogen futures. However, despite broad agreement that hydrogen could make a significant contribution to energy policy goals, the literature exhibits strong disagreements about the form that a future hydrogen economy should take. Visions of the future select, combine and reconfigure individual hydrogen generation, storage, transport and end-use technologies into more or less mutually compatible energy and transportation systems, which embody deeply contested and conflicting views of sustainability. This paper describes the application of a novel foresight methodology, which combined participatory scenario development, using a backcasting approach, with an expert-stakeholder multi-criteria mapping (MCM) process, in order to provide an integrated, transparent assessment of the environmental, social and economic sustainability of six possible future hydrogen energy systems for the UK. The findings suggest that: hydrogen has the potential to deliver substantial sustainability benefits over the status quo, or, business as usual, futures, but that hydrogen is not automatically a sustainable option; carbon emissions are the single most important dimension of sustainability, but that issues other than carbon and cost need to be considered if hydrogen is truly to deliver greater sustainability. Furthermore, there was significant disagreement about which visions were considered more or less sustainable. These findings reflect two important sources of divergence in the final sustainability rankings: uncertainties and contested views of sustainability.  2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. Keywords: Multi-criteria appraisal; Backcasting scenarios; Sustainable hydrogen economy 1. Introduction In recent years the concept the ‘hydrogen economy’ has received considerable attention, with the emergence of a broad based ‘advocacy coalition’ [28], comprising a diverse range of academic researchers, politicians, business and civil society organisations, promoting hydrogen as a means of delivering a sustainable and secure energy system. As a result there is a wide and growing literature promoting and exploring different possible hydrogen futures. However, despite broad agreement that hydrogen could make a significant long-term contribution to energy policy goals, the literature exhibits strong disagreements about the form that a future hydrogen economy should take. Visions of a hydrogen future select, ∗ Corresponding author. E-mail address: malcolm.eames@brunel.ac.uk (M. Eames). 0360-3199/$ - see front matter  2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2007.06.020 combine and reconfigure individual hydrogen generation, distribution and end-use technologies into more or less mu- tually compatible energy and transportation systems, which embody deeply contested and conflicting views of sustain- ability [1]. In short, there is no single, shared vision of a ‘sustainable hydrogen economy’. Rather, different organisations and indi- viduals produce visions and expectations of possible hydrogen economies that reflect their own interests and values [2]. For some, hydrogen is a means of maintaining current systems, structures and ways of life; for others, it has the potential to re- order energy in ways that may facilitate broader social change. Despite the range of different possible hydrogen systems that the literature embodies, the few studies that attempt to appraise the relative sustainability of different hydrogen futures tend to do so on the basis of a rather limited set of criteria (typically carbon emissions, cost, and air pollutants, for example, [3]),