In seeking both to tackle climate change and ensure that the UK has a secure supply of affordable energy, the UK Government is proposing a significant expansion in the generation of energy from renewable sources. Under the Renewable Energy Directive, the UK is committed to providing renewable sources for 15% of its total energy use by 2020. While there is considerable theoretical potential, a number of socio-economic constraints threaten the achievement of this target. This research develops a more quantitative understanding of such constraints for two renewable energy sources with significant potential; perennial energy crops, and onshore wind power. For perennial energy crops such as Short Rotation Coppice (SRC) Willow, and Miscanthus, a major constraint is the extent to which UK farmers will commit land to the production of these relatively novel crops. For onshore wind power, a key constraint is that of public perception, related primarily to the visual impact on landscapes. The research uses a number of approaches, drawing on socialpsychology techniques, mathematical programming, and cost-benefit analysis, to develop a better understanding of the nature and extent of key barriers. As a result, a number of policy relevant findings lead to the identification of cost-effective ways in which barriers to development can be addressed.