There are currently 308 GW of coal-fired capacity and 185 GW of gas-fired capacity in operation in the United States. Assuming normal operating lives, 95% of the coal capacity and 99% of the gas capacity will be retired by 2050. These retirements must be replaced with new capacity—be it coal, gas, or otherwise.
Yet during 2006–2009, investor-owned utilities canceled 23.1 GW of proposed coal projects, building only 3.3 GW.
Recent political and economic developments have made it difficult to complete a coal-fired power plant. For example, in 2007, a powerful trio of investment banks—Morgan Stanley, Citi, and J.P. Morgan Chase—announced that they would finance new coal-fired power plants only if the developer could demonstrate economic viability under a future carbon price. In the same year, a Georgia Superior Court Judge revoked an air pollution permit issued to a 1,200 MW coal-fired power plant—the first time CO2 was cited as a factor in denying an air pollution permit. In 2008, Illinois passed a mandate that new coal-fired plants must capture and store 50–90% of their CO2 emissions (depending on plant commissioning year). Several utilities and energy companies, including Progress Energy, Oklahoma Gas & Electric, and TXU Corporation, placed short-term moratoriums on building new coal-fired power plants.
For more information on the age of U.S. power plants currently in operation (of all fuel types), see the Energy Information Administration’s article:
U.S. Energy Information Administration. 2008. "Existing Electric Generating Units in the United States". Washington, D.C.: U.S. Department of Energy.
U.S. Energy Information Administration. 2009."New U.S. Electric Generating Units by Operating Company, Plant and Month". Washington, D.C.: U.S. Department of Energy, December.
U.S. Energy Information Administration. 2010. "New U.S. Electric Generating Units by Operating Company, Plant and Month". Washington, D.C.: U.S. Department of Energy, December.