This joint report by the International Energy Agency and the OECD Nuclear Energy Agency is the ninth in a series of studies on electricity generating costs. As countries work towards ensuring an electricity supply that is reliable, affordable and increasingly low carbon, it is crucial that policymakers, modellers and experts have at their disposal reliable information on the cost of generation. This report includes cost data on power generation from natural gas, coal, nuclear, and a broad range of renewable technologies. For the first time, information on the costs of storage technologies, the long-term operation of nuclear power plants and fuel cells is also included. The detailed plant-level cost data for 243 power plants in 24 countries, both OECD and non-OECD, is based on the contributions of participating governments and has been treated according to a common methodology in order to provide transparent and comparable results.