In energy consumption, individuals feature a gap between intention and action. Survey data from the US, the UK, and other European countries show that 50-90% of respondents favour energy from renewable sources, even at a small premium. Yet less than 3% actually buy renewable energy. We investigate how nudges - a slight change in the information set that an individual faces when taking a decision - can help individuals align behaviour with intention. We present evidence from an original survey experiment on which nudges affect the choice whether to contract renewable energy or conventional energy. We find that only a default nudge has a significant effect, while all other nudges prove ineffective. In our setting, a default nudge increases the share of individuals who choose renewable energy by 44.6%. (C) 2014 Elsevier Ltd. All rights reserved.