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Nuclear Energy Has New Appeal as Climate Pressures Mount

Though a large share of the country’s clean electricity comes from nuclear power plants, states have made plans to retire them. But as they set steeper emission targets, many are reconsidering the role of nuclear energy.

Power Plant.jpg
A nuclear power plant in Illinois.
The recent Supreme Court decision limiting the scope of the federal government’s greenhouse reduction efforts was described as a “body blow” to the country. The ruling came during one of the warmest Junes in more than a century, in a year that had already seen nine billion-dollar weather and climate disasters.

Greenhouse gas emissions trended upward in 2021. By the end of the year, a 17 percent increase in coal-fired power generation and a jump in freight transportation pushed levels 6.2 percent higher than the year before.

Globally, human-caused emissions of all groups of greenhouse gases are continuing to rise, according to the most recent report from the Intergovernmental Panel on Climate Change. Every possible tool and strategy will be needed to stay anywhere near the limit of 1.5 degree Celsius of warming the Paris Agreement hopes to achieve, the threshold for even more dangerous climate impacts.

These pressures have set the stage for another look at nuclear power in the zero-carbon energy mix. Nuclear plants generate 20 percent of the nation’s electricity, more than half of its clean electrical power and more than all other emission-free sources combined.

According to the U.S. Energy Information Administration (EIA), 93 commercial nuclear reactors were operating in 28 U.S. states at the end of 2021, the most of any country in the world. As of November 2021, another 23 were in various stages of decommissioning.

This is the wrong direction, says Kathryn Huff, the scientist serving as assistant secretary for nuclear energy at the U.S. Department of Energy. “To achieve our nation’s carbon reduction goals, we must aim to prevent closure of any and all nuclear power plants that can be licensed to continue operating.”

The Bipartisan Infrastructure Law included $6 billion for a Civil Nuclear Credit Program to support plants at the highest economic risk of closure.

Running in Reverse

Electricity production is responsible for a quarter of all U.S. greenhouse gas emissions, and 60 percent comes from fossil fuels. The Biden administration has set a goal of net-zero energy production by 2035, and nuclear sources can make contributions during this transition, and beyond.

The “capacity factor” of nuclear power plants — the amount of time they are actually producing power — is over 92 percent, much greater than green stalwarts solar and wind and significantly greater than hydropower. Only geothermal energy, productive almost three-fourths of the time, comes close. But at present only about .4 percent of electricity is generated using geothermal power.

These differences also mean that it could take three or four wind or solar plants, consuming vast amounts of land, to put the same amount of emission-free electricity on the grid as one nuclear plant could. (Nuclear plants have twice the capacity factor of coal and gas facilities.)

The “always on” nature of nuclear generation can also help ensure an uninterrupted electricity supply compared to the intermittent generation of power by solar and wind.

The EIA projects that the share of all electricity generated from nuclear power will decline from 20 percent to 12 percent by 2050. Huff believes that advanced reactor technologies, if validated in a demonstration and deployment program, could reverse this trend. A nuclear production tax credit proposed in the House, if passed, could support innovation as well as keeping plants open.

To date, lost nuclear power generation has been replaced by fossil plants. “In the race to reduce emissions, the closure of emissions-free nuclear generation is a step backward,” says Huff. “Replacing those assets with unmitigated fossil generation is doubly antithetical to the mission, like running in reverse.”
Diablo Canyon, California’s last nuclear power plant, was scheduled to close in 2025. Gov. Newsom now plans to apply for federal funds to keep it open.
(Joe Johnston/TNS)

Reconsidering Nuclear Assets

California’s last operating nuclear power source, the Diablo Canyon Power Plant, exemplifies the hurdles that emerge in the pursuit of emission reductions. In 2018, the California Public Utilities Commission approved a settlement that would lead to the permanent closure of the plant in 2025.

However, California has set a goal of zero carbon by 2045, and Diablo Canyon is its single largest source of carbon-free electricity. In addition, the state has committed to setting aside 30 percent of its land for conservation purposes, constraining opportunities for building large solar or wind arrays.

In 2021, a group of scientists from Stanford and MIT published an assessment of the potential energy, economic and environmental benefits from keeping the plant open until 2035, or beyond. They estimated that delaying the retirement by 10 years could save California $2.6 billion in power system costs and reduce power sector emissions by 10 percent compared to 2017 levels. Operating the plant to 2045 and beyond, they said, could save as much as $21 billion in system costs and avert the need to use 90,000 acres of land for energy production.

In addition, they said, the plant’s firm capacity “would be especially valuable during electric reliability events” noting that the absence of power from Diablo Canyon during outages in 2020 would have tripled the state’s electricity shortage. In April of this year, California Gov. Gavin Newsom told the Los Angeles Times that California would pursue federal funds to keep the plant open.

Economist John Parsons, associate director of MIT’s Center for Energy and Environmental Policy Research, was an author of the Diablo Canyon report. California isn’t the only state to rethink its policy regarding nuclear power, he says.

“You’ve seen the same thing happen in other states — New York, Illinois, New Jersey, Connecticut — they were all expecting many of their nuclear plants to close, but as they begin to really chart a path to decarbonization, the numbers looked daunting,” says Parsons. “It dawned on them how valuable the assets that they had were, and so they have changed their tune.”

In their study, Parsons and his colleagues looked beyond Diablo Canyon’s contributions to the state’s clean electricity supply. They also considered the benefits attainable from using the plant to power desalination and recharge overdrafted water basins and to produce clean hydrogen, suggesting that the integration of different technologies to produce power could increase the plant’s value by 50 percent.
The laboratory for the U.S. Department of Energy's Office of Nuclear Energy, the Idaho National Laboratory leads the country's nuclear energy R&D efforts.

We Need Everything

Attaining a net-zero economy by 2050, the goal set by the Biden administration, means moving entirely away from the fossil fuels that now provide 80 percent of the country’s energy resources — not just for electricity generation, but for industry and transportation.

Nuclear engineer Shannon Bragg-Sitton, director of the Integrated Energy and Storage Systems Division at Idaho National Laboratory (INL), is certain that nuclear power will play a long-term role in the country’s energy sector. “We need everything,” she says. “If we have a non-emitting energy source, we need to be using it; wind and solar and hydro are great resources, but they do have limitations.”

Nuclear currently provides just under 20 percent of the country’s electricity, but heat is the fundamental output of a nuclear reaction, she says. The heat could be used directly for industrial applications — an emission-free substitute for heat generated by fossil fuel combustion. This could be enabled by co-locating users and producers.

At present, some plants produce more energy than users need and pay to have it taken from them. The excess could be used to produce hydrogen, a valuable clean energy asset with multiple applications.

The advent of the small modular reactor (SMR), with lower output and a significantly smaller footprint that can be factory built and assembled, will create new opportunities for co-location and distributed power generation, even though deployment is years away.

SMRs could be a solution to the high cost and long timelines involved in building new plants that have made it difficult to add new nuclear capacity. These next-generation reactors can change both elements of this paradigm. Bragg-Sitton is aware of more than 60 private-sector developers working on SMRs.

“We’ve got to actually build some of these systems, get them online and prove the concepts,” she says. “Then they will take off on their own, and we’ll see more rapid development; we’re starting to see the opportunity to completely change the way economics works for nuclear.”

The nation’s first SMR project is being built on DOE-owned land west of Idaho Falls where INL is located.
UAMPS SMR Plant.jpg
The Carbon Free Power Project of the Utah Associated Municipal Power Systems will be the nation's first to generate power from small modular reactors. It is expected to be operational in 2030.

Carbon Free Power Project

The Utah Associated Municipal Power Systems (UAMPS), a nonprofit providing energy services in the Rocky Mountain region, launched the Carbon Free Power Project (CFPP) in 2015 to generate electricity from small modular nuclear reactors.

“For decades, the NRC [Nuclear Regulatory Commission] process has been very long and onerous,” says UAMPS spokesperson LaVarr Webb. “These modules will be built in factories rather than onsite like the traditional reactors, and it has required the NRC to think in new and different ways.”

The first step was to obtain approval for the reactor technology, which was developed by NuScale Power. The process took several years and involved millions of pages of documentation, says Webb, but it was completed and the NuScale reactor became the first SMR to be approved by the NRC.

Now UAMPS is working to obtain a license to build and operate the plant, another extensive process that will involve such things as seismic testing, surveys, two years of meteorological data and completed planning and engineering. The application will be submitted by January of 2024, and construction could begin in 2025 or 2026.

The CFPP will have six reactors, each capable of generating 77 megawatts of power. It is expected to be operational in 2030 and will be the first SMR plant to come online in the U.S.

UAMPS has 50 members in seven states; 27 are participating in the CFPP. The DOE has approved a $1.35 billion cost share for the project, most of which will be used to finance preparatory work and the early stages of construction.

At present, CFPP expects the cost of its power to be $58 per megawatt hour over the life of the project. “If you built a new natural gas plant, it would probably cost you about $70 per megawatt hour,” says Webb. “So, $58 per megawatt hour is a very good price for stable, dispatchable, carbon-free energy.

Having the nation’s premier nuclear energy research lab as a partner was one of the smartest decisions in the planning of CFPP, says Webb. “DOE wants to see these SMRs be successful to deal with climate change, but also so that the United States maintains leadership in nuclear innovation and development and we don't cede all of that to Russia and China.”
The partial meltdown of a reactor at the now-closed Three Mile Island plant did not result in injuries, deaths or direct health effects on the public. Even so, it affected public perceptions and public approval of nuclear power remains mixed, a 2022 Pew survey found.
(Dan Gleiter/TNS)

Nuclear Dilemma

A 2018 report from the Union of Concerned Scientists, The Nuclear Power Dilemmaattracted wide attention for recommending continued support for nuclear plants, provided that it came with “rigorous safety, security and performance requirements.” This embrace of nuclear power by the respected environmental nonprofit was celebrated by the American Nuclear Society, which characterized it as a “political seismic shift.”

Edwin S. Lyman, the director of nuclear power safety with the Union of Concerned Scientists and the co-author of Fukushima: The Story of a Nuclear Disaster, didn’t contribute to the 2018 report. He retains concerns about the safety of nuclear power.

“There are two separate baskets of issues,” says Lyman. One is whether existing plants should be subsidized, and another is whether new plants should be built. Both involve financial and safety criteria, and he has concerns that the safety criteria for plants receiving federal funds to stay in operation are not stringent enough.

There are also technical uncertainties regarding the long-term disposal of nuclear waste, Lyman says. “How do you predict the performance of a geological repository of hundreds and thousands and millions of years? There’s fundamental work that can be done, but the larger issue is the inability to develop a process that could find a site that’s both technically and politically acceptable.”

The NRC has authority over plant safety, but state and local officials would do well to take their own look at issues such as seismic risk. Lyman is also concerned about the amount of spent nuclear fuel stored in pools at nuclear facilities.

If too much water drains from them, as came very close to happening during the Fukushima accident, the fuel could catch fire and release radioactive smoke. A major fire of this sort could “dwarf” the consequences of Fukushima, Lyman told Science.

Bragg-Sitton points out that the amount of used nuclear fuel from the commercial nuclear industry is small. “We know where every bit of it is, and we have technical solutions that can be implemented, but we have some political challenges associated with pushing them through,” she says.

The Right Mix

Risks are value judgments, according to MIT’s Parsons, who served as co-chair of an exhaustive 2018 study of the future of nuclear energy. He says the total number of people who have died or had health problems as a result of nuclear power is extremely small.

Germany has been closing nuclear facilities, he notes, replacing them with coal-fired power plants that over time will damage health in predictable and quantifiable ways that are far beyond what any nuclear plant has done. “I appreciate why the public is very concerned, but the track record compared to the alternatives is very good.”

Over time, innovation in technologies such as long-duration storage and geothermal could compete with nuclear power, says Michelle Solomon, a policy analyst in the Power Sector Transformation program at Energy Innovation.

“If you provide the right mix of renewables, such that they're compatible with each other, you can meet a lot of the same base load power needs,” Solomon says. “A really diverse portfolio of renewable resources can sometimes have a bigger role than we realize.”

“There are always many ways to achieve something,” Parsons says of the pursuit of zero-carbon energy. “But I think it's obvious that we should keep most of the existing nuclear plants — it’s such a cost-efficient contribution that if we chose not to I would worry that we're not really keeping our eye on the ball.”
Carl Smith is a senior staff writer for Governing and covers a broad range of issues affecting states and localities. He can be reached at or on Twitter at @governingwriter.
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