Stretching from Hunterston, Ayrshire, to Connah’s Quay, Flintshire, the cable is arguably the key element of the Scottish government’s renewable energy network. Data collected by the Renewable Energy Foundation (REF), showed that £39.4 million had been paid in “constraint payments” to energy companies while it was down.
Operators of onshore wind farms receive constraint payments to power down turbines when electricity supply outstrips demand and bottlenecks in the grid prevent exports. The money is paid out by National Grid ESO but is charged to consumers through electricity bills.
Concerns about the reliability of the interconnector have been heightened by the failure of another subsea cable, the £515 million BitNed link between the Isle of Grain, Kent, and Maasvlakte in the Netherlands. An “unplanned outage” on March 9 is not expected to be repaired until May 8. The interconnector is said to be “vital to the energy needs of Great Britain and the northwestern European region”.
John Constable, the director of REF, who has been accused of campaigning against wind farms, said: “UK and Scottish energy policy is dependent on electricity interconnectors, but reliability issues put that policy in jeopardy. A firm intervention from the regulator Ofgem is long overdue.” Ofgem said it was investigating the latest incident.
National Grid Electricity System Operator said it used its assets to balance supply and demand “second by second, always choosing the most efficient mix to keep costs down for consumers”. It added: “ The alternative to constraint payments is building more electricity transmission assets which is more costly, meaning bills would rise.”
Western Link became fully operational in October 2018, three years behind schedule. Its record for reliability was “abysmal”, Constable said.
A spokeswoman for National Grid Electricity Transmission said: “The cause of recent failures has been isolated to a section of the cable of 1km length which will be replaced later this year at no extra cost to consumers.”