Nuclear powerAn Atomic Catch 22: Climate Change and the Decline of America's Nuclear Fleet

By Eric Scheuch

Just outside of Harrisburg, Pennsylvania, lies the shuttered hulk of America’s most infamous nuclear power plant: Three Mile Island. The site of a commercial nuclear accident in 1979, the worst of its kind in American history and an event which helped spark much of the modern anti-nuclear movement, Three Mile Island ceased operations in 2019. The closure came from a mixture of political opposition and simple economics. Nuclear energy in the United States has become deeply unprofitable in the last decade, driven by a combination of aging infrastructure and other electricity sources like renewables and natural gas simply becoming cheaper to build and operate. While some in the environmental community may cheer nuclear’s decline, others are concerned. Love it or hate it, nuclear plays a unique role in the American electric sector, one for which we currently have no market-ready replacement, and its decline will likely make other environmental issues, particularly climate change, harder to solve.

Since the first American commercial nuclear power plant opened in Pennsylvania in 1958, nuclear energy has played a key role in the U.S. energy sector. Currently providing approximately 19 percent of the country’s electricity generation, nuclear energy is America’s leading zero-carbon energy source, generating more electricity than all renewable sources combined in 2018. Nuclear energy is also an important source of what is known as “baseload power,” or the minimum amount of electricity that is needed by the grid at any given time. Since reactors are very hard to shift up and down in their output and to turn on and off, they make an ideal source of baseload power for the grid — nuclear reactors can, and in some ways must, run at the same level regardless of outside factors. The difficulty with replacing nuclear energy is that we lack a strong, cost-competitive, alternative source of zero-carbon baseload energy. We have cost-competitive sources of zero-carbon energy, like wind and solar, but they tend to be intermittent. We have cost-competitive sources of baseload power like natural gas, but they come with higher carbon emissions than nuclear. Illustrating the critical role of non-intermittent baseload sources to a reliable grid, a recent paper found that having just five percent of electricity sources stay constant, as nuclear does, will halve electricity prices compared to relying fully on wind and solar, even when the latter is paired with battery storage.