This sixth study in a series on projected costs of generating electricity presents and analyses cost estimates for some 130 power and co-generation (heat and power) plants using coal, gas, nuclear and renewable energy sources. Experts from 19 OECD member countries, 2 international organisations and 3 non-member countries contributed to the study. The levelised lifetime costs presented and analysed were calculated with input data from participating experts and commonly agreed generic assumptions, using a uniform methodology. Key issues related to generation costs are addressed in the report, including methodologies to incorporate risk in cost assessments, impact of carbon emission trading and integration of wind power into electricity grids. A reference in the field, this publication will be of interest to energy policy makers, electricity system analysts and energy economists.