EDF Energy’s top priority for the UK is to deliver value from the Sizewell B NPP, according to its annual fleet update, which reviews 2025 performance and outlines future developments. “Nuclear is not weather dependent and Sizewell B achieved a load factor of 99% for the year, generating 10.4 TWh or over 30% of total UK output. Progressing a 20-year life extension opportunity (2035 to 2055) is a priority but dependent on agreeing the appropriate commercial model to ensure such an extension is viable,” EDF noted. Work continues to agree a commercial model that is required to support life extension and unlock £800m of investment in the station.
The other priorities are to:
- maximise output from the four generating Advanced Gas-cooled Reactor (AGR) nuclear stations – Hartlepool (County Durham) scheduled for closure by March 2028, Heysham 1 (Lancashire) scheduled for closure by March 2028, Heysham 2 (Lancashire) scheduled for closure by March 2030, and Torness (East Lothian, Scotland) scheduled for closure by March 2030.
- defuel the AGR stations efficiently – these include Dungeness B (Kent), which ceased generation in June 2021, Hinkley Point B (Somerset), which ceased generation in 2022 and Hunterston B (Ayrshire, Scotland), which ceased generation in 2022.
- seamlessly transfer them to Nuclear Restoration Services (NRS) and to develop our long-term future, recognising that by the mid-2030s all seven of the AGR stations will be owned by the UK Government.
However, “maintaining a strong nuclear safety track record remains the over-riding priority”.
EDF said that, since acquiring the nuclear fleet in 2009, EDF has invested around £8.6bn ($11.5bn) and will invest a further £1.2bn over the next three years (2026-28) “to help sustain current levels of generation, boost energy security and cut carbon”. In 2025, EDF’s Nuclear Operations business expects to pay around £400m in taxes.
Since 2009, “UK’s nuclear stations have generated 263 TWh more electricity than expected through life extensions and better operational performance”. UK nuclear output in 2025 totalled 32.9 TWh – this was lower than 2024 but more than three times the output anticipated at the point of acquisition in 2009. The objective is to achieve about 36 TWh of output in 2026. “The UK imported some 21 TWh from France in 2025, the majority of which will have been generated by French nuclear reactors.”
EDF noted that the estimated generating lifetimes of the Hartlepool and Heysham 1 NPPs had been extended by a further one year (to March 2028). “EDF’s ambition is to generate beyond these dates, subject to plant inspections, reliability and regulatory oversight.”
EDF said it continues to deliver on its defueling contract with two of the decommissioning stations now free of used nuclear fuel. Hunterston B and Hinkley Point B are on schedule to transfer to NRS in 2026.
As to new nuclear, “We are working with government and private companies to develop the future of our sites with plans starting to be shaped for new nuclear at Cottam and Hartlepool. Heysham in Lancashire and Torness in Scotland are both sites with lots of advantages for new developments.”
EDF noted: “Since our last stakeholder update in January 2025 there have been several significant developments in the UK nuclear industry with financial close for Sizewell C and plans for new nuclear developments at Cottam, Hartlepool and Wylfa, signalling growth not seen for decades.”
EDF’s UK Nuclear Operations business is 80% owned by EDF Group and 20% by Centrica plc and employs around 5,000 people at 10 main sites. EDF and Centrica “have an ambition to generate from the AGR power stations until at least 2030, subject to plant inspections, reliability and regulatory support.
Dr Mark Hartley, Managing Director of EDF’s Nuclear Operations business said: “In November, the UK Government said that the retirement of the AGRs risks leaving a dangerous gap in Britain’s low-carbon energy supply. It is our ambition to generate from the remaining AGR stations for as long as it is safe and commercially viable to do so and we will keep their lifetimes under review to assess whether further life extensions can be achieved.
He added: “Sizewell B had a strong year, operating for 99% of the time and delivering the second highest output in its 30-year history, once again demonstrating the value of nuclear as a stable baseload generator.”
