National Grid Electricity Transmission plc (NGET) has today agreed to pay £20 million into Ofgem’s Energy Industry Voluntary Redress Scheme after it accepted it had failed in monitoring, maintaining and repairing the Harker 132kV substation near Carlisle, Cumbria between November 2016 and November 2021. The substation connects to the 132kV transmission network in Scotland, making it part of the overall network capability across the Anglo-Scottish border.
Embedded generation (including renewable generation) has been seeking to connect to the distribution network in the region. An Ofgem investigation, launched in March 2022, concluded that NGET delayed the connection of embedded generation.
Separately, Ofgem has asked NGET to present a plan by the end of March for five areas where an independent review found it could make improvements. The review, by DNV, followed a 2025 fire in a substation serving Heathrow airport. The airport was closed after the substation fire.
DNV said NGET generally adheres to good asset-condition, health data management and general asset management practices. But it suggested NGET should:
• Review differences with international standards for in periodic maintenance requirements for main plant.
• Review performance targets for key maintenance activities against industry benchmarks and best practice (e.g. scheduled maintenance, target dates for defects and bushing oil sampling) and publish these within NGET.
• Review escalation processes for deferred maintenance to ensure timely follow-up, including engagement with NESO where scheduled outages are being delayed due to outage constraints. Put in place key performance indicators for deferred activities
• Set out how NGET plans to improve compliance for oil testing for transformer bushings, with a deep dive into transformer bushing oil sampling and a review of wording in maintenance guidance documents
• Provide regular updates on progress with implementing the new asset management platform, and improvements to scheduling and tracking maintenance activity, monitoring and reporting.