Nuclear power in the United States  Nuclear power in the United States is provided by 96 commercial reactors with a net capacity of 98 gigawatts (GW), 64 pressurized water reactors and 32 boiling water reactors. In 2019 they produced a total of 809,409 thousand megawatt hours of electricity, which accounted for 20% of the nation's total electric energy generation. In 2018, nuclear energy comprised nearly 50 percent of U.S. emission-free generation.  , there are two new reactors under construction with a gross electrical capacity of 2,500 MW, while 34 reactors have been permanently shut down. The United States is the world's largest producer of commercial nuclear power, and in 2013 generated 33% of the world's nuclear electricity. With the past and future scheduled nuclear plant closings, the United States could lose its position to China and Russia. As of October 2014, the NRC has granted license renewals providing a 20-year extension to a total of 74 reactors. In early 2014, the NRC prepared to receive the first applications of license renewal beyond 60 years of reactor life, as early as 2017, a process which by law requires public involvement. Licenses for 22 reactors are due to expire before the end of the next decade if no renewals are granted. The Fort Calhoun Nuclear Generating Station was the most recent nuclear power plant to be decommissioned, on October 24, 2016. Another five aging reactors were permanently closed in 2013 and 2014 before their licenses expired because of high maintenance and repair costs at a time when natural gas prices have fallen: San Onofre 2 and 3 in California, Crystal River 3 in Florida, Vermont Yankee in Vermont, and Kewaunee in Wisconsin, and New York State is seeking to close Indian Point in Buchanan, 30 miles from New York City. Most reactors began construction by 1974; following the Three Mile Island accident in 1979 and changing economics, many planned projects were canceled. More than 100 orders for nuclear power reactors, many already under construction, were canceled in the 1970s and 1980s, bankrupting some companies. Up until 2013, there had also been no ground-breaking on new nuclear reactors at existing power plants since 1977. Then in 2012, the NRC approved construction of four new reactors at existing nuclear plants. Construction of the Virgil C. Summer Nuclear Generating Station Units 2 and 3 began on March 9, 2013 but was abandoned on July 31, 2017 after the reactor supplier Westinghouse filed for bankruptcy protection on March 29, 2017. On March 12, 2013 construction began on the Vogtle Electric Generating Plant Units 3 and 4, the target in-service date for Unit 3 is November 2021.