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UK nuclear output falls again as Scottish AGR is shut down
Electricity generation at one of the UK’s nuclear power stations, the Hunterston B Advanced Gas-cooled Reactor (AGR) in North Ayrshire, Scotland, has ended after almost 46 years. Reactor 4 at the EDF-run site was shut down at midday on 7 January.
Since the station came online in 1976 it has produced enough zero carbon electricity – almost 300 TWh – to power every home in Scotland for nearly 31 years, says EDF. Originally planned to operate for 25 years, investment in the plant meant an extension to 46 years was possible. The station’s other unit, Reactor 3, was taken offline in November 2021.
Both reactors will now undergo a statutory outage to make sure they are ready for the defueling stage, where the nuclear fuel is removed from the reactors and transported by rail to Sellafield for storage. Defueling at Hunterston B is expected to take around three years.
EDF has been consulting with staff about their futures for the past two years, with the majority indicating that they would like to continue working at Hunterston B. All of those have secured an ongoing role through defueling, says the company. Others have been supported to move to other EDF sites and some have opted to retire.
Under a contract agreed with the government in June 2021, EDF will carry out defueling at all seven of the UK’s AGR stations before the sites are transferred to the Nuclear Decommissioning Authority (NDA) for its subsidiary, Magnox, to continue with decommissioning.
The closure of Hunterston B is only part of an ongoing programme of closure of the oldest nuclear plants in the UK as they reach the end of their operational lives. Electricity generation from the UK’s nuclear power plants fell by 9% in 2021 to just 46 TWh, less than half the peak in 1998 and the lowest in nearly four decades, according to the Carbon Brief website.
The 9% drop in 2021, due to retirements and outages at ageing reactors, contributed to a record 17 TWh fall in low-carbon electricity last year, say Carbon Brief. Wind generation also fell by 15% during the year, primarily due to lower wind speeds.
As a result, the carbon intensity of UK electricity generation rose last year by nearly 10% to 199 grams of carbon dioxide (CO2) per kWh (gCO2/kWh), up from a record-low 183 gCO2/kWh in 2020, according to analysis by Carbon Brief. The figures had previously been falling for several years. Electricity generation from fossil fuels was therefore 9% higher than a year earlier, of which nearly 90% came from higher gas output. Coal’s share remained below 2% compared with a year earlier, while gas increased its share from 34% to 37%.
Nevertheless, low-carbon sources still generated more than half of UK electricity in 2021, including 19% from wind, 14% from nuclear, 12% from biomass and 4% from solar, says Carbon Brief.
Hunterston B nuclear power station