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Three Mile Island (TMI) Unit 1 located in Londonderry Township, Dauphin County, in Pennsylvania, generates 852 megawatts of clean, safe and reliable electricity for more than 800,000 homes.

As we look to the future, power needs across central Pennsylvania and the United States are projected to increase and there is growing concern about climate change. To help meet that growing demand, and to help keep our environment clean, Exelon Nuclear, owner of TMI Unit 1, applied in January 2008 to the U.S. Nuclear Regulatory Commission (NRC) for a 20-year extension to the plant's operating license. The current license expires in 2014. With license extension, TMI can continue to provide central Pennsylvania with safe, clean, reliable power until 2034.

Without TMI Unit 1, the region would need an alternative energy source to meet electricity demand. By replacing TMI Unit 1 with a coal-fired power plant similar in size, 271 metric tons of carbon dioxide per hour would be emitted into the environment by the coal plant. The operation of Three Mile Island avoids harmful air emissions, and improves the air quality of the region.