EDF and Centrica are extending the lifetime of two British nuclear power plants with a combined 2.3 GW by another year to 2028, the companies announced Sept. 2.

The 1.15-GW Heysham 1 and 1.1-GW Hartlepool plants in northern England will now run until March 2028, adding up to 15 TWh of additional power supply. EDF's UK unit owns 80% in the reactors, while Centrica has a 20% stake. Both Heysham 1 and Hartlepool are comprised of two advanced gas-cooled reactors.

"Extending the life of these stations makes sense. It secures employment for longer for more than 1,000 people who work at those sites, and it supports the UK's ambitions to have a clean, secure electricity supply," said Mark Hartley, managing director of EDF Energy's nuclear operations business.

Extended operations at Heysham 1 and Hartlepool will also reduce the need for imported gas, Hartley added.

The Heysham 2 and Torness plants are still expected to shut in March 2030, after having their lifetimes extended in December 2024.

Graphite cracking, for which there is no known solution beyond reducing the output of an impacted reactor, is the main life-limiting factor in the operations of EDF Energy's AGR fleet and has already led to the early closure of some units. However, in the case of the four AGRs at Heysham 1 and Hartlepool, graphite cracking is not really an issue at present, based on a series of recent inspections, a spokesperson for EDF Energy said Sept. 2.

The spokesperson said that, based "on a series of inspections over the last nine months," the decision to proceed with the life extensions was "almost exclusively due" to the lack of graphite cracking, adding that there was no cracking at Hartlepool and that cracking was "at the very earliest stages" at Heysham 1.

According to Centrica, the additional extensions announced Sept. 2 would boost its share of power supply by 3 TWh, which would be a total 15 TWh from the two plants for Summer 2027 and Winter 2027.

Total UK nuclear life extensions announced since last December are projected to add approximately 12 TWh to Centrica's generation volumes between 2026 and 2030, which would be a total 60 TWh for the plants.

Centrica also recently acquired a 15% equity stake in the 3.2-GW Sizewell C reactor project in England, with committed construction funding of GBP1.3 billion.

"We believe in having a diversified energy system, with nuclear power playing a key role in ensuring stability and sustainability for decades to come," Centrica CEO Chris O'Shea said.

The EDF Energy spokesperson also said that while the current end date for Hartlepool and Heysham 1 was 2028, the "ambition is to go for longer [have further life extensions]," as it was at all of the remaining eight AGRs in the UK.

Platts, a unit of S&P Global Commodity Insights, last assessed UK summer 2027 baseload power at GBP69/MWh, while winter 2027 was pegged at GBP78.45/MWh.