While most studies of low-carbon transitions focus on green niche-innovations, this paper shifts attention to the resistance by incumbent regime actors to fundamental change. Drawing on insights from political economy, the paper introduces politics and power into the multi-level perspective. Instrumental, discursive, material and institutional forms of power and resistance are distinguished and illustrated with examples from the UK electricity system. The paper concludes that the resistance and resilience of coal, gas and nuclear production regimes currently negates the benefits from increasing renewables deployment. It further suggests that policymakers and many transition-scholars have too high hopes that ‘green’ innovation will be sufficient to bring about low-carbon transitions. Future agendas in research and policy should therefore pay much more attention to the destabilization and decline of existing fossil fuel regimes.