A welcome and unexpected result from COP28 Dubai was a pledge as part of the stock-taking process by twenty-four participating countries “to work together to advance a global aspirational goal of tripling nuclear energy capacity from 2020 by 2050, recognizing the different domestic circumstances of each Participant.” The pledge is an important aspirational statement that recognizes the unique contribution nuclear energy makes as a baseload power source in comparison to intermittent solar and wind renewable energy. Beyond producing power, nuclear energy can also produce high-temperature steam necessary to decarbonize industrial sectors such as steel and cement. The statement also reflects the changed opinion among many (but not all) public and private groups that nuclear energy’s benefits for combatting climate change balance its risks—notably safety, waste management, and proliferation.

Not surprisingly, nuclear industry groups welcomed this initiative. The International Atomic Energy Agency (IAEA) stated the pledge “demonstrates there is now a global consensus on the need to scale up this (nuclear) clean and reliable technology to achieve our vital goals on climate change and sustainable development.” In the IAEA’s ambitious annual nuclear power projections, the high case for global installed nuclear power will reach 890 GWe by 2050, compared to 369 GWe today; a tripling would mean 1,107 GWe installed by 2050.

Growth of this magnitude implies expansion to countries that do not presently have nuclear power, so-called “embarking” countries. Much to their credit, three organizations, the Energy Futures Initiative Foundation, the Clean Air Task Force, and the Nuclear Threat Initiative, collaborated on a report presented at the Dubai conference outlining pathways for the responsible and effective development of new nuclear energy projects. The report suggests six essential areas for attention: project execution, regulatory system, project bankability, and finance, nuclear nonproliferation and security, spent fuel, and workforce development.

Not all observers have noticed the Dubai nuclear announcement. The Financial Times, in its December 15 report on the Dubai COP, identified “COP Commitments that Really Count,” mentions control of methane emissions, tripling renewable energy generating capacity to at least 11,000 GWe by 2050, and increasing the rate of energy efficiency improvement by a factor of two, but did not mention nuclear energy. Neither did Robert Stavins, in his annual Harvard Kennedy School COP report, mention the nuclear announcement.

The six areas mentioned in the global playbook are general and appropriate for a thirty-year time horizon that anticipates significant international expansion for nations embarking on nuclear power. However, to reach the future, today’s prospects for nuclear energy also deserve attention. The outlook for nuclear expansion in the United States, the country with the largest number of deployed reactors, about 22 percent of the world total, faces immediate challenges, including extending the lifetime of the existing fleet; establishing a record of declining unit reactor overnight capital costs; adopting a stable system for comparing the cost generation alternatives; extending the lifetime of the existing fleet. The existing fleet of ninety-three reactors with 95 GWe capacity has an average age of about forty-two years. There has been a steady decline since 2012 in the number of operating reactors for several reasons. Still, summer generation has held steady because the industry has maintained high-capacity utilization rates. Seven reactors (about 5.5 GWe) have retired over the past five years for a variety of reasons.

Recent federal legislation (the Inflation Reduction Act and the Bipartisan Infrastructure Act) established a production tax credit (Section 45Y) and an investment tax credit (Sec. 48) to delay further retirements. However, eventually, reactors that have commercial value will need to go to the Nuclear Regulatory Commission for license extensions. Maintaining the existing nuclear fleet, which provides about 18 percent of U.S. electricity, deserves the highest priority.

Establishing a record of declining unit reactor overnight capital costs to ~$3,000 per kWe-hr is essential to attract the private investment necessary to build new nuclear power plants. During the past decade, the industry has shifted its attention from constructing relatively large scale ~1,000 MWe pressurized and boiling water reactors to considering small modular reactors, SMRs ≤ 300 MWe. It is widely believed that SMRs will be of lower cost than the disastrous cost levels experienced at the Vogtle, GA, and abandoned V.C. Summer, South Carolina, plant construction. Accordingly, SMRs have attracted a great deal of private and federal investment, but low overnight capital cost has yet to be demonstrated.

Optimism arose beginning in mid-2022 that nuclear deployment in the United States was entering a period of growth. The GE-Hitatchi BWRX-300 MWe SMR was selected for deployment by the Ontario Power Group at its Darlington site. It is under consideration by Saskatchewan’s SaskPower and the TVA at Clinch River, Tennessee. NuScale, partnering with Utah Associated Municipal Power Systems (UAMPS), planned to combine twelve 77 MWe pressurized water modules to produce a 924 MWe plant at the Department of Energy’s (DOE) Idaho Falls ID site by 2030.

The DOE’s GEN IV Advanced Reactor Demonstration Program selected X-Energy’s Xe-100 high-temperature gas reactor (four 80 MWe modules ganged together to produce 320 MWe) and TerraPower’s 345 MWe molten salt Natrium reactor, each to receive $110 million 50/50 cost share. X-Energy has selected DOW’s Seadrift TX chemical plant as its first location. TerraPower was selected at a retired coal plant at Kemmerer, WY, which PacifiCorp will operate.

Toward the end of 2023, expectations collapsed. COVID-19, unexpected inflation, and high borrowing rates have caused all the early participants to extend their anticipated completion dates, exceed initial cost targets, and indicate additional financing will be needed. After the massive budget outlays of the Bipartisan Infrastructure Act and Inflation Reduction Act legislation, it is unlikely that major additional support will come from the federal government.

In November, NuScale announced the cancelation of its UAMPS project, delivering a major setback to nuclear energy expectations. The DOE has provided $232 million for the project since 2020, and the department has backed the project with a $1.4 billion cost-share deal. The project was abandoned because of the substantial cost overruns and the unwillingness of UAMPS members to pay higher prices for the off-take electricity.

Accordingly, the United States will not have acquired a record declining unit cost on SMR reactors, at least until the mid-2030s.

Designing a method for comparing the costs of baseload nuclear power and intermittent renewable power is a complex matter. The low unit costs for wind and solar must be augmented by storage costs to avoid shedding demand in supply scarcity. As the requirement for meeting demand in all conditions increases, storage costs climb, and nuclear power costs compared to renewable power plus storage costs decline and eventually will be less.

Electricity pricing also plays a vital role in this process. Replacing constant volume-based pricing with time-of-day pricing can dramatically reduce the profile of renewable plus storage costs. Recall that nuclear electricity generation, not power capacity, determines carbon-free emissions. This places a premium on high-capacity factors, which in turn depend on electricity pricing, especially the generation dispatch rules. Without an agreed process for comparing electricity configuration’s cost, it is impossible to assess the likelihood of a tripling of nuclear electricity generation in either the United States or countries “embarking” on nuclear power across the globe.

In sum, we are confronted with an aspirational goal for the growth of international nuclear energy deployment at mid-century and a decidedly guarded assessment of nuclear energy progress today based on conditions in the United States, the country with the largest deployment of nuclear reactors and a history of leading the world in nuclear technology. The role nuclear energy might play in the future global energy mix should be supported by realistic analysis, not hope about what might be accomplished on hypothetical pathways.

John Deutch, an emeritus Institute Professor at MIT, was director of energy research, deputy secretary of energy, as well as deputy secretary of defense and director of central intelligence in the Clinton administration.

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