The power sector represents one of the largest end-use sectors and totals over 21 percent of all global emissions. Emissions in this sector are driven by the combustion of fossil fuels that result in the release of CO2 and other greenhouse gases. Coal, the fuel that produces the most emissions per unit of energy created, is the largest of all fuel sources used, accounting for up to 41 percent of the global electricity generation in 2009. Fossil fuels account for 67 percent of all electricity generated.