EDF’s Torness plant east of Edinburgh has previously been taken offline due to jellyfish

This article is more than 2 years old

This article is more than 2 years old

Roving jellyfish and seaweed have long been unwanted guests at Scotland’s last two nuclear power stations. Now the marine algae have hit again, forcing one of the plants to partially power down despite freezing temperatures pushing up demand for electricity.

During last week’s cold weather, excessive amounts of seaweed entered the cooling system of the Torness plant in East Lothian, causing one reactor to be closed on Thursday.

Its owner, EDF Energy, said the measure had been taken due to the “risk of marine ingress”. After several days of reduced output, the power station was gradually returning to full power on Monday.

Freezing weather costs UK economy £1bn a day Read more

Together with Hunterston on the west coast, the plants normally provide about a third of Scotland’s electricity needs.



An EDF spokesperson said: “We know that at certain times of year particular weather conditions in this part of the Forth estuary can lead to increased seaweed volumes which can enter the station’s cooling water intake system. Our staff are trained to respond in this situation, and to take the plant offline if necessary.”

It is not the first time that Torness has been affected by seaborne nuisances. The site was closed twice in 2013 due to seaweed clogging the plant’s cooling system, and jellyfish caused the plant’s units to temporarily shut down in 2011.

Torness, which opened in 1988, was scheduled to close in 2023 but two years ago EDF Energy announced it was extending the plant’s lifetime to 2030 to maintain secure electricity supplies.



Several of the UK’s other eight remaining nuclear power stations are due to shut earlier, in the 2020s.

Heysham nuclear power station in Lancashire and Sizewell B in Suffolk are also running at reduced power, due to planned maintenance.

However, during the recent freezing weather, Britain’s nuclear sector has been consistently providing about a fifth of UK electricity supplies.

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EDF Energy, along with other generators, will have benefited from high power prices in the past few days, a knock-on effect of the extremely strong gas demand for heating.

Wholesale electricity prices, which are normally about £45 per megawatt hour, reached spikes of £990/MWh on Thursday, the coldest spring day on record. Prices remained high on Monday, hitting £109/MWh in the morning.

Analysts ICIS said weekend power prices were roughly double the average seen in 2017.

Britain’s rapidly dwindling fleet of coal power stations have surged in the past few weeks, with coal providing a quarter of electricity on Saturday.

Experts at Bernstein bank said the “beast from the east” would have been particularly positive for Drax, which runs a large coal and biomass power station in North Yorkshire.

• This article was amended on 8 March 2018 because an earlier version abbreviated megawatt hour to mWh.