Sizewell C Nuclear Project Costs Soar as £38 Billion Deal Finalized

The construction of the Sizewell C nuclear power plant in Suffolk will cost approximately £38 billion, nearly double the original budget, following a significant investment agreement finalized by the UK Government. Energy Secretary Ed Miliband announced the deal on July 22, 2025, which officially greenlights the long-anticipated project.

The soaring costs come as energy bills for consumers are set to increase by an average of £1 per month during the construction phase, beginning in the autumn. The Department for Energy Security and Net Zero (DESNZ) confirmed that the UK Government will hold a 44.9 percent equity stake in Sizewell C, making it the largest shareholder.

New investors include the Canadian investment firm La Caisse with 20 percent, Centrica, the owner of British Gas, with 15 percent, and Amber Infrastructure with an initial stake of 7.6 percent. Following the announcement, Centrica’s shares rose by 4 percent. French energy firm EDF, which had previously indicated a 16.2 percent stake, will now contribute 12.5 percent to the project.

Project Impact and Long-Term Goals

Once operational, Sizewell C is expected to power approximately six million homes and create around 10,000 jobs. The project is anticipated to begin generating power in the 2030s. Miliband emphasized the importance of this investment, stating, “It is time to do big things and build big projects in this country again… This government is making the investment needed to deliver a new golden age of nuclear.”

The total investment will surpass the £38 billion target, which is intended to act as a buffer against potential cost overruns. The National Wealth Fund, the government’s investment vehicle, is providing the majority of the debt financing, amounting to up to £36.6 billion. This agreement marks a significant milestone for the Sizewell C project, which has been in the pipeline since its initial development plan was proposed in 2010.

The anticipated benefits include estimated savings of up to £2 billion per year across the low-carbon electricity sector once the plant becomes operational. The DESNZ reported that the cost of developing Sizewell C is approximately 20 percent lower than that of the Hinkley Point C nuclear power station, which is currently under construction in Somerset and is scheduled to open in 2031.

Government Commitment to Energy Independence

Chancellor Rachel Reeves highlighted the strategic importance of this development, noting it will help reduce the UK’s reliance on foreign energy sources. “This is a public-private consortium… taxpayers will get a return on that investment,” she stated. Reeves underscored that the participation of La Caisse, Centrica, and Amber Infrastructure signifies confidence in the UK as a viable hub for nuclear energy.

Nuclear power is increasingly viewed as a crucial component of the UK’s strategy to decarbonise its electricity grid by 2030, replacing fossil fuels with renewable energy sources. The last nuclear power station completed in the UK was Sizewell B in 1987.

Chris O’Shea, the Chief Executive of Centrica, expressed optimism regarding the project, describing it as “a compelling investment for our shareholders and the country as a whole.” He emphasized that this initiative represents not just a commitment to a new power station, but also to Britain’s energy independence and the journey towards net-zero emissions.

Investment Director at AJ Bell, Russ Mould, remarked on the dual nature of the project, stating, “Sizewell C might generate a significant amount of jobs and energy… yet its overall cost has nearly doubled from the previous estimate.” This highlights the ongoing financial challenges associated with large-scale infrastructure projects in the energy sector.

As Sizewell C moves forward, the government remains focused on enhancing energy security and fostering economic growth through significant investments in clean energy infrastructure.