The purpose of this study is to compare the energy efficiency of fossil-fired power generation for Australia, China, France, Germany, India, Japan, Nordic countries (Denmark, Finland, Sweden and Norway aggregated), South Korea, United Kingdom and Ireland, and United States. Together these countries generate 65% of worldwide fossil power generation. Separate benchmark indicators are calculated for the energy efficiency of natural gas, oil and coal-fired power generation, based on weighted-average energy efficiencies. These indicators are aggregated to an overall benchmark for fossil-fired power generation. The weighted average efficiencies are 35% for coal, 45% for natural gas and 38% for oil-fired power generation. The Nordic countries, Japan and United Kingdom and Ireland are found to perform best in terms of fossil power generating efficiency and are, respectively 8%, 8% and 7% above average in 2003. South Korea and Germany are, respectively 6% and 4% above average and the United States and France are, respectively 2% and 4% below average. Australia, China and India perform 7%, 9% and 13%, respectively below average. The energy savings potential and CO2 emission reduction potential if all countries produce electricity at the highest efficiencies observed (42% for coal, 52% for natural gas and 45% for oil-fired power generation), corresponds to 10 EJ and 860 Mtonne CO2, respectively. (c) 2007 Elsevier Ltd. All rights reserved.