This contribution examines the EU’s innovative climate and energy package: how this package of binding policies has been initiated, decided, implemented and reformed. The key argument is that linking climate and energy concerns can help to explain how the EU managed to adopt an ambitious package of policies aimed at achieving 2020 goals. The combination of differently valued issues, side-payments to overcome distributional obstacles and the creation of synergies contributed to a successfully negotiated outcome. The consequences for implementation and further policy development towards 2030 are explained by challenges in reproducing these joint EU-level gains at national level, and by new circumstances. This may weaken the EU’s chances of realizing a low-carbon economy and ‘leadership by example’ in international climate policy.