As part of policies to combat climate change, there is a global commitment to increase the proportion of electricity generated from renewable energy sources, including hydro‐electric, wind, solar and geothermal. This reduces the use of fossil fuels such as coal, oil, and gas, which produce CO2 emissions and so contribute to climate change. National and global policies for renewable energies reflect the result of public debates and democratic decisions. This briefing is based on a number of PSIRU reports on the energy sector, all of which are available on the PSIRU website