Sizewell C Secures Private Investment Backing for £38 Billion Nuclear Deal

After more than a decade of uncertainty, shifting investors, and concerns over public funding, the UK Government has finally secured private-sector backers for the Sizewell C nuclear power plant. A final investment decision, taken yesterday (22 July), locks in a massive £38 billion commitment to the long-awaited project, marking a pivotal moment in Britain’s energy strategy.

As of late 2024, the UK Government held a commanding 84% stake in Sizewell C, a figure many feared would remain unless private investors stepped up. Today, that picture has undergone a dramatic shift.

Under the new structure, the Government retains the most significant single share at 44.9%. However, it is now joined by an international consortium: Canadian giant La Caisse with a 20% stake, British utility Centrica with 15%, France’s EDF with 12.5%, and Amber Infrastructure, which rounds out the ownership with 7.6%.

EDF, the original project developer, remains in the driver’s seat.

“La Caisse’s decision to take a 20% stake in the project reflects growing international backing for UK nuclear and confidence in Sizewell C. As one of the world’s leading institutional investors, La Caisse brings significant experience in sustainable infrastructure and in delivering projects that drive economic growth and long-term value creation,” said the Sizewell C management team in a statement.

Meanwhile, La Caisse, one of the world’s most prominent institutional infrastructure investors with CAD 64 billion in assets, brings deep credibility to the deal. Nearly 40% of its infrastructure portfolio is already concentrated in the energy sector, further underscoring its long-term commitment to the industry.

The inclusion of these players didn’t happen overnight. Their entrance comes after years of wrangling—much of it triggered by the controversial departure of China General Nuclear (CGN) due to national security concerns. That departure, while politically expedient, left a significant hole in the financing plan. It’s taken until now to fill it.

Sizewell C isn’t just another infrastructure project; it’s a generational investment. With an expected operating life of at least 60 years, the plant represents a long-term anchor in the UK’s low-carbon energy transition.

But it hasn’t come cheap. Original cost estimates hovered around £20 billion. Now, with inflation and global supply chain pressures, the final bill has nearly doubled in price. Still, the Government insists the numbers add up. Ministers argue that the plant will save £2 billion annually in electricity system costs compared to alternatives that rely heavily on renewable energy sources.

Consumers, too, are being reassured. Officials claim that, throughout construction, the average household will see bills rise by no more than £1 per month.

The project's roots stretch back to 2009, when then-Energy Secretary Ed Miliband earmarked Sizewell C as one of eight sites for future nuclear expansion. More than 15 years later, it’s finally moving forward—but full operations aren’t expected until the mid-2030s.

Sizewell C’s economic impact is expected to be substantial. Government estimates suggest 10,000 direct jobs will be created at the peak of construction, alongside 1,500 apprenticeships. Roughly 70% of supply contracts are expected to be awarded to UK firms, providing a much-needed boost to the domestic industry.

Yet not everyone is celebrating.

Residents and environmental groups have voiced deep concerns. The campaign group Together Against Sizewell C has launched a High Court challenge against EDF’s proposed coastal defence infrastructure. Backed by the RSPB, the group fears that irreversible damage will be caused to the Suffolk Coast and Heaths Area of Outstanding Natural Beauty.

Marine ecosystems are also in the spotlight. Critics warn of disruption caused by the plant’s cooling system, which requires substantial water abstraction and discharge, an intervention that could impact local biodiversity.

Nonetheless, the project has passed key regulatory milestones. In spring 2025, Sizewell C was granted a nuclear site licence, following updated environmental impact assessments.

The years of waiting and political wrangling may be over. But with construction, litigation, and environmental mitigation all ahead, the real challenge for Sizewell C may just be beginning.