Sizewell B operations extended for another 20 years

EDF-OWNED power station Sizewell B is set to run for two decades more than its expected end-of-life date as part of the UK’s efforts to keep energy prices low.

As part of Contracts for Difference between the energy company and the UK government, the nuclear power station will now run until 2055 and run at a fixed cost of £70.50/MWh in 2025 prices starting from 2035. The cost will be supported by investment from British energy company Centrica.

The government said that the deal will “reduce the costs of Britain’s energy system” and “strengthen energy security”.

Based in Suffolk, Sizewell B is the UK’s only pressurised water reactor and produces around 9 TWh/y of electricity – around 3% of the UK’s total electricity needs.

'Critical' upgrades

If the deal goes ahead, EDF will invest around £800m (US$1bn) into the plant for “critical” maintenance works and upgrades, including replacing infrastructure and fitting in a new automated plant operating system and environmental monitoring system – similar to the one being built at Hinkley Point C.

EDF says these works will be delivered across the next 15 years, during the station’s planned outages that take place every 18 months.

A spokesperson for the UK’s Office of Nuclear Regulation said: “Safety cases at Sizewell B are likely to require updating to achieve EDF’s stated ambition, together with investment in plant to sustain equipment reliability, all while ensuring that the necessary people and skills are available throughout the extended lifetime.

“The ongoing safety and security of operations at any nuclear site must be fully demonstrated to us as part of ongoing regulation, which will be informed by our extensive, proportionate and targeted inspection and assessment regime.”

Fixed cost

A fixed energy price for the extension follows news of mounting costs for EDF’s highly-anticipated and expensive Sizewell C nuclear project.

Estimated to cost around £38bn, the funding for Sizewell C includes taxpayers also footing the bill for construction.

This model pushed more risk towards taxpayers, according to the UK’s National Audit Office, which said that the funding model relied on the “big assumption” that a £4 increase on energy bills will save consumers around £18bn once the site is open.

Taxpayers began paying for Sizewell C in November 2025. The UK’s Department for Energy Security Net Zero predicted that energy cost will rise up to £17-19 by 2039, the site’s expected opening.