Security of energy supply and climate change are central concerns for policy makers and important dimensions of the long-term quest for a sustainable global energy system. This paper examines the role of several policy instruments in managing energy security and climate risks and stimulating technological change towards a more secure and climate-benign global energy system in the long-term future. The analysis has been conducted with ERIS, a multi-regional energy-systems "bottom-up" optimization model with technology learning. Our analysis provides some policy insights and identifies synergies and trade-offs relating to the potential for security of supply policies to promote the uptake of new technologies, reduce the cost of pursuing climate change mitigation policies, and facilitate a possible transition to a hydrogen economy. (c) 2005 Elsevier Ltd. All rights reserved.