Nuclear energy is a vital part of America's energy portfolio. Currently, there are 99 nuclear power plants operating in 30 states, supplying approximately 20% of the country's electricity without generating greenhouse gases. But recently, cheap natural gas from hydraulic fracturing and relatively low electricity demand growth has pushed many of America's nuclear reactors into early retirement. Five nuclear power plants have retired since 2013 in Florida, Wisconsin, California, Vermont and Nebraska. Six more plans, including Three Mile Island and Diablo Canyon in California, have announced that they will close between now and 2025, even though they could technically operate for many more years. Several more plants in Ohio, New Jersey, Pennsylvania and Connecticut are also at high risk of shutting down. Although these numbers are likely to change due to recent policy changes aimed at retaining some of the struggling plants, the underlying challenges remain. When those reactors retire, it would not only take enormous amount of clean energy off the grid but also it would have negative consequences on local communities.