Only one nuclear plant to bid in T-4 Capacity Market auction

Only one nuclear plant has prequalified for the upcoming four-year-ahead (T-4) Capacity Market auction for delivery starting in 2025/26.

Tom Edwards, senior modelling consultant for Cornwall Insight, described the absence of the Torness and Heysham 2 nuclear power stations from the prequalification register as “very worrying” as they were the last advanced gas-cooled reactor plants to be commissioned in Britain and were expected to continue operating until the end of the current decade.

More than 53.2GW of de-rated capacity has prequalified for the T-4 auction, of which around 33GW is existing generation. Just two nuclear units from Sizewell B in Suffolk have prequalified, representing 990MW of de-rated capacity.

Edwards said the Torness and Heysham 2 power stations in Lancashire and East Lothian are still expected to be running in 2025/26 and he has seen no indications of operational difficulties at the plants so far.

But he said EDF’s decision to withhold them from the auction suggests it would “rather not take the risk” of being exposed to termination fees. He said the company has already been forced to terminate Capacity Market agreements for other plants in its nuclear fleet after being unable to meet satisfactory performance requirements.

He noted that the decision means Torness and Heysham 2 plants will also be “locked out” of the year-ahead (T-1) auction for 2025/26.

According to EDF’s website, both power stations are expected to cease generating in 2030, with Sizewell B going five years later in 2035. Heysham 1 and Hartlepool are scheduled for closure in March 2024.

In August 2020, EDF announced it would cease generation at Hunterston B by January 2022 – at least a year earlier than previously planned – due to the deterioration of the graphite bricks that make up the reactor cores, and the following November, the company brought forward the closure of Hinkley B by eight months to July 2022 for the same reason.

In June of this year, EDF announced that it would immediately begin decommissioning Dungeness B, which had been offline since 2018, after finding faults at the plant.

The procurement target for the T-4 auction was provisionally set at 42.1GW in July by the energy minister energy and clean growth minister at the time, Anne-Marie Trevelyan.

Edwards said the secretary of state for energy will likely lower the target to reflect the absence of Torness and Heysham when they finalise the figure in January: “They are supposed to adjust the auction capacity at that point to take into account things like plant that has opted out but will remain operational”.

He said if the target is not reduced, this will open up opportunities for the many gigawatts of new capacity competing in the auction.

Nearly 11.3GW of new build generation has prequalified, with gas generation and battery storage accounting for the vast majority at around 8.6GW and 2.5GW respectively. There is also nearly 25MW of onshore wind and 10MW of solar as well as Highview Power’s liquid air energy storage facility – dubbed a CryoBattery – being built by the company in Greater Manchester.

The prequalifying capacity additionally includes: 170MW of refurbished generation; almost 4.2GW of existing interconnectors; three new build interconnectors – North Sea Link, Viking Link and ElecLink – with a combined capacity of nearly 2.8GW; around 199MW of unproven demand-side response (DSR); and 199MW of proven DSR.

Notably, the Sutton Bridge and Severn Power combined-cycle gas turbine plants, bidding as refurbished generation, were both rejected from the auction.

The power stations were placed into a “dormant” state in August 2020 after the owner, Calon Energy, went into administration the month before. The company’s directors regained control of the plants in May of this year.

Around 5.5GW of de-rated capacity has prequalified for the year-ahead (T-1) auction for 2022/23, for which the procurement target is currently 4.5GW.

Just over 3.1GW of existing generation has prequalified, including the fourth unit at Uniper’s Ratcliffe-on-Soar coal-fired power station. The second and third units have already secured agreements in the T-3 auction for 2022/23.

There is additionally more than 1.6GW of new generation, including around 1.3GW of gas generation and 378MW of battery storage, as well as 564MW of unproven DSR and 173MW of proven DSR.

Both the T-1 and T-4 auctions are due to take place in February.