UK National Grid interim report on blackout expected next week

London — The UK's National Grid interim technical report into the blackout on August 9 is expected to be published next week (week 34) giving regulator Ofgem time to deliberate on the report, a source close to the matter said Friday.

UK energy regulator Ofgem asked Monday for an "urgent detailed report" from National Grid by Friday to decide on next steps after two generators failed causing blackouts across England and Wales.

National Grid said August 10 it had launched an investigation into why the generators failed within seconds of each other.

The outages occurred last Friday at 16:54 BST at the Little Barford gas plant in Bedfordshire and the Hornsea One offshore wind farm off the Yorkshire coast.

This caused frequency on the 50 Hz transmission grid to drop to 48.9 Hz.

A media report suggested that a lightning strike on power lines may have contributed to the shutdowns of the generators, the Times newspaper reported Friday.

National Grid declined to comment on the report when contacted by Platts.

Earlier this week, National Grid ESO denied media reports of similar frequency deviation incidents earlier this year.

"All the time until Friday's events, the system has remained within safe limits," National Grid said in one of five brief media statements this week.

"We work with Ofgem to set the agreed limits of frequency of electricity output to keep the whole system safe," it said.

WIND FARM TECHNICAL FAULT

Wind farm operator Orsted said Friday its 800 MW Hornsea One offshore wind farm did experience a technical fault.

"During a rare and unusual set of circumstances affecting the grid, Hornsea One experienced a technical fault which meant the power station rapidly de-loaded," a spokesperson said in a statement Friday.

"Normally the grid would be able to cope with a loss of this volume," the spokesperson said. "The relevant part of the system has been reconfigured and ... should this extremely rare situation arise again, Hornsea One would respond as required."

The UK government, meanwhile, launched its own review into the blackout.

"The Energy Emergencies Executive Committee will establish what happened to cause the outage and if correct procedures were followed," the Department for Business, Energy and Industrial Strategy (BEIS) said Wednesday.

The committee will provide a report on its initial findings within five weeks to the secretary of state for business, followed by a comprehensive report within 12 weeks.

Energy minister Kwasi Kwarteng was visiting the National Grid control room on Friday, the grid operator said.

The review will complement the investigation being undertaken by the energy regulator Ofgem into how the electricity operator responded in line with its license conditions and system security standards.

"National Grid has already confirmed that the incident was not linked to the variability of wind power," business secretary Andrea Leadsom said.

The committee is a partnership between the government, the regulator and industry, which co-ordinates resilience planning across the energy industry.

-- Andreas Franke, andreas.franke@spglobal.com

-- Edited by James Burgess, newsdesk@spglobal.com