UK extends Sizewell B’s life to 2055 with £1.2 billion deal

UK ministers and EDF agreed terms that will keep Sizewell B running for another 20 years, extending the Suffolk reactor’s operating life to 2055 and preserving a large block of low-carbon nuclear generation while Britain’s new-build pipeline stays uncertain.

The deal turns the UK’s only operating pressurised water reactor into a longer-term fixture of the electricity system. Sizewell B first supplied power to the grid on 14 February 1995, was built between 1987 and 1995, and was originally due to close in 2035 after a 40-year life. EDF says the station has already produced more than 270 terawatt hours of low-carbon electricity and now covers around 3% of UK electricity demand, enough to power about 2.5 million homes.

The extension rests on a 20-year Contract for Difference running from 2035 to 2055 at a strike price of £70.50 per megawatt hour in 2025 prices. That level is below the agreed strike price for Hinkley Point C and sits under current wholesale electricity prices, giving the plant a long tail of predictable revenue while the government tries to keep existing clean generation online.

EDF said it will fund about £800 million of refurbishment work over the next 15 years during planned outages. The wider investment support tied to the extension totals about £1.2 billion over 2026 to 2028 and includes a new environmental monitoring system, new automated plant-monitoring systems, and replacement of pipework, valves and pumps across the site. EDF says the package could secure about 900 jobs at the plant for longer.

The government has cast the agreement as part of a wider attempt to protect billpayers, skilled jobs and domestic supply chains. Centrica, which holds a 20% stake in Sizewell B, backed the deal. Simone Rossi, EDF UK’s chief executive, Ed Miliband, the energy secretary, Lord Vallance, the science minister, and Centrica chief executive Chris O’Shea all framed the extension as a win for energy security and long-term clean power supply.

The Office for Nuclear Regulation said life-extension decisions do not need formal permissioning, but valid safety cases still have to be maintained and reviewed. The regulator said it works in an enabling manner, assessing technical and safety-case issues while making sure safety and security standards are met.

Sizewell B now matters as more than a single asset. Government material describes it as the last nuclear reactor opened in the UK, and the country currently has eight operational nuclear power stations. With Hinkley Point C, Sizewell C and small modular reactors in Anglesey still forming the next wave, the Sizewell B extension keeps a major slice of Britain’s nuclear fleet on the board well into the 2050s.