Is the U.K. finally reversing its nuclear decline?

Posted: June 17, 2025

Last week, the U.K. government announced a £16.5 billion investment in British nuclear energy, including £14 billion to build a new nuclear power station and a £2.5 billion investment in small modular reactors (SMRs). The announcement reverses a longstanding decline of nuclear energy in the U.K.

Britain’s nuclear decline

In the 1990s, nuclear made up around 25% of the U.K.’s annual electricity generation. Over the years, older plants shut down and were not replaced and today, nuclear accounts for only around 15% of the U.K.’s total energy portfolio, with 6.5 GW of total nuclear capacity.^[1]

While the 1986 Chernobyl disaster certainly didn’t help nuclear power’s popularity, it’s not the only reason for its decline. The 1990 privatization of Britain’s formerly nationalized electricity saw utilities reducing their workforces, cutting overhead, and reducing investment in nuclear. As Joe Renshaw recently explained in China’s nuclear know-how, a government that invests in publicly funded nuclear power helps ramp up production by shifting the risk and financial considerations from private entities to the state.

The recent uptick in public funding for nuclear in the U.K. is partly due to a new finance model for large-scale infrastructure. The government’s regulated asset base model gives a company a licence to charge consumers a regulated price in exchange for providing the infrastructure, enabling investors to share some of the project’s construction and operating risks with consumers. The model means consumers pay a small extra charge on their utility bills during construction.

The U.K.’s nuclear capacity is predicted to continue to fall for the next five years as eight of the U.K.’s nine aging nuclear reactors reach their scheduled closing dates. In 2031, Hinkley Point C—a nuclear power station that began construction in Somerset in 2017—is due to come online six years later than originally planned, providing the U.K.’s first new nuclear power station in over 35 years. Sizewell C, over 15 years in the planning, will connect to the grid a few years later. Its design and capacity are a replica of Hinkley Point C, making the Sizewell C build a supposedly quicker and cheaper venture than the much-delayed Hinkley project.

Sizewell C: Clean energy for six million homes

The new Sizewell C power station will perch on the Suffolk coast, close to the previous nuclear sites of Sizewell A and B. Sizewell A opened in 1967 and was decommissioned in 2006. Sizewell B remains the U.K.’s newest nuclear power station—despite opening 30 years ago—and is slated for decommissioning in 2035, although its operator, EDF, hopes to extend its life by another 20 years.^[2]

The two-reactor Sizewell C site will add 3.2 GW of energy to the U.K.’s supply, enough to power about six million homes with low-carbon, reliable energy. It promises to provide 10,000 jobs and 1,500 apprenticeships during construction and pour £4 billion into the regional economy.

The U.K. government sees investing in nuclear as integral to its plan to diversify, decarbonize, and domesticate the country’s energy production, reducing its dependence on imported fossil fuels. Simone Rossi, CEO of EDF in the U.K., said, “Nuclear is essential to a secure, low-carbon energy system and is the ideal partner to renewables.”

Government stats released in March 2025 showed that in 2024, renewable energy sources made up 50.8% of Britain’s electricity generation, surpassing half of total generation for the first time. If you include “low-carbon” nuclear, that percentage rises to 65%. But there’s still a long way to go. “We need new nuclear to deliver a golden age of clean energy abundance, because that is the only way to protect family finances, take back control of our energy, and tackle the climate crisis,” said Ed Miliband, the Secretary of State for Energy Security and Net Zero.

The Sizewell C website claims the reactor will help the U.K. avoid 9 million tons of carbon emissions each year it operates. The Sizewell C Consortium is also planning to use other net-zero technologies on site with the reactor—it has partnered with the University of Nottingham, Strata Technology, Atkins, and Doosan Babcock to build a demonstrator direct air carbon capture unit that can extract 100 tons of CO₂ from the atmosphere each year. The consortium hopes to develop a full-scale system, powered by heat from the nuclear power station, that could one day capture 1.5 million tons of CO₂ annually.^[3] Once the site is operational, it could also produce low-carbon hydrogen, using nuclear energy to power an electrolyzer.

Rolls-Royce SMRs: U.K.’s first modular reactors

While Sizewell C is under construction, small modular reactors could provide a way to increase the country’s nuclear capacity quickly and relatively affordably. Recently, the government announced that it had selected Rolls-Royce SMR to build the country’s first three SMRs, which are expected to power the equivalent of around 3 million homes. The company says each of its SMR power stations will occupy the footprint of two football pitches, and their modular construction means the government can select sites more flexibly than for a full-scale nuclear power station.

The power plants are almost entirely manufactured and assembled in factories before being installed on site. The modular approach “de-risks” building a nuclear power station “very, very, very substantially”, Sir Stephen Lovegrove, chair of Rolls-Royce SMR, told the Guardian in January.

Nuclear provides stable baseload power (unlike renewable energies such as wind, which can fluctuate and place demands on the grid), helping to create a more resilient clean energy system. While critics have described nuclear as slow and expensive, many agree that the world can’t meet its net-zero climate goals without increasing nuclear capacity. The National Energy System Operator, responsible for managing and planning the U.K.’s energy system, says that while the U.K. is committed to expanding zero-carbon renewables like wind and solar, “nuclear power will continue to be a key generation source on the road to net zero in 2050.” Last week’s announcements have finally set that plan back in motion.

To learn more about baseload power and the importance of SMRs, look out for our upcoming podcast episode with Steve Holliday, former CEO of National Grid.

^{[1] Nuclear power in the U.K, World Nuclear Association
[2]Investment boost to maintain UK nuclear output at current levels until at least 2026, EDF
[3] Sizewell C and partners awarded direct air capture funding, Sizewell C}