Failing nuclear power is good for coal, bad for earth.

Scana Corp. announced Monday it will stop construction on a nuclear power plant in South Carolina—one of two in development in the U.S. Project costs ballooned in recent years, and the decision should eventually save electricity customers $7 billion. 

But the stoppage and others like it may cost everyone more in the long run. The move has implications that last hundreds of years—the residence time of heat-trapping carbon dioxide in the atmosphere—as electricity generated from fossil fuels begin to replace aging or expensive nuclear reactors. 

Nuclear power has long provoked ardent policy fights, historically centered on the perceived safety or danger of splitting atoms to keep consumers’ refrigerators running. Since America’s most famous close-call—the 1979 partial reactor meltdown at Three Mile Island—debates have only grown in complexity.

Today, it’s not local or environmental opposition but economics that’s crippling industry growth and undercutting the fiscal viability of existing plants. A natural gas installation coming online in 2022 might cost $14 a megawatt-hour in apples-to-apples capital costs, according to the Energy Information Administration’s 2017 Annual Energy Outlook. Nuclear plants would need more than $70/MWh. (The latest EIA outlook doesn’t project coal costs because under Obama-era regulations, none were expected to be built.)

Low natural gas prices are undercutting even the relatively cheap costs of operating many online U.S. nuclear plants, making some of them too expensive to run. 

Among those existing reactors, Three-Mile Island is the latest victim of the U.S. shale gas boom, and to some extent, reduced demand and increased renewables. It’s now expected to close in 2019. Four states that have shuttered nuclear facilities in recent years have turned to gas and coal to make up the difference. 

More gas and coal, of course, means more emitted carbon dioxide. And that’s exactly what scientists say we need to reduce in order to slow climate change, or at the very least avoid global environmental catastrophe. 

But renewable energies like solar and wind aren’t enough to replace fossil fuels, at least not yet. This is where nuclear comes in. It may be very difficult to meet international carbon-cutting goals without widespread addition of nuclear plants. The Deep Decarbonization Pathways Project is an international research effort into how leading polluters’ may need to transform their energy systems to cut carbon below levels identified as safe by scientists. The U.S. analysis, which was conducted by the consultancy Energy and Environmental Economics Inc. and two national laboratories, found that electricity demand might double by 2050—while the amount of CO2 emitted per dollar of GDP would need to fall to between 3 percent and 10 percent of current levels. The report lays out three main scenarios that would achieve such dramatic reductions.

• A renewables scenario, which calls for about 30 times 2015 capacity.
• The coal scenario, which would require roughly doubling current coal-generated power (provided it has carbon-capture and storage technology that doesn’t exist). 
• The “high-nuclear” scenario.

This third option calls for a quadrupling of 2015 U.S. nuclear power production. And with Scana nixing 2.2 gigawatts of construction, Three-Mile Island’s announced closure, and the generally weak state of the industry, the U.S. isn’t showing much capacity to even hold the line. 

“Without an aggressive build-out of nuclear power, climate goals are still attainable, but at much greater expense,” according to Jeffrey Sachs, the economist and director of the Sustainable Development Solutions Network, which co-leads the Deep Decarbonization effort. “The rest of the options are still feasible, but less attractive,” he said. “We’d make a big mistake if we decide right now we don’t need it.”

The V.C. Summer Nuclear Station near Jenkinsville, South Carolina.

Photographer: Chuck Burton/AP

Asked how to overcome the unfavorable economics that killed the South Carolina project and is shuttering active plants, Sachs suggested a rethinking of the entire nuclear research, development, and deployment pipeline. Newer technologies—some being pursued in other countries—may dramatically reduce costs, if they prove safe. 

A magic wand solving the cost problems would still leave the problem of waste, and give policymakers a choice between nuclear waste—deadly but concentrated poison that lasts thousands of years—and fossil-fuel waste—invisible, diffuse carbon pollution that in sufficient amounts will transform the Earth for thousands of years. 

Some climate skeptics may cite this as a Hobson’s choice, but experts warn that it’s not that simple, especially when considering the economic component. While nuclear waste is nasty stuff, so are the conventional pollutants of fossil-fuel burning. The Brattle Group has previously found that “nuclear power avoids air emissions of over one million tons of sulfur dioxide and 650,000 tons of nitrogen oxides each year, as well as significant particulate emissions.” Restricting these toxins saves America more than $9 billion a year.

Emissions cuts made today are worth more than the same cuts made down the road, authors of a Brattle Group report wrote in December. “Since CO2 emissions persist for many years in the atmosphere,” they said, “near-term emission reductions are more helpful for climate protection than later ones.”