The chapter advances the argument that policies promoting renewable energy versus carbon-based technologies can simultaneously realise maximal gains from three types of opportunity cost calculations. To the extent that they reduce GHG emissions per capita while increasing energy access, they maximize climate justice. To the extent that they increase energy access for underserved individuals and communities while reducing GHG emissions per capita, they maximize energy justice. And to the extent that either or both types of improvement entail greater scope for meaningful popular participation in the governance of new energy systems in terms of policy design, implementation, and employment, they maximise development goals and human rights, and in particular, the human right to participation. The chapter uses insights from grid decentralisation and political decentralisation in order to illustrate these three claims.