In this action, the Environmental Protection Agency (EPA) is establishing final emission guidelines for states to follow in developing plans to reduce greenhouse gas (GHG) emissions from existing fossil fuel-fired electric generating units (EGUs). Specifically, the EPA is establishing: Carbon dioxide (CO<INF>2</INF>) emission performance rates representing the best system of emission reduction (BSER) for two subcategories of existing fossil fuel-fired EGUs--fossil fuel-fired electric utility steam generating units and stationary combustion turbines; state-specific CO<INF>2</INF> goals reflecting the CO<INF>2</INF> emission performance rates; and guidelines for the development, submittal and implementation of state plans that establish emission standards or other measures to implement the CO<INF>2</INF> emission performance rates, which may be accomplished by meeting the state goals. This final rule will continue progress already underway in the U.S. to reduce CO<INF>2</INF> emissions from the utility power sector.