Orsted is investigating after an outage hit its 1218MW Hornsea 1 offshore wind farm, contributing to a wider power system failure that left hundreds of thousands of people across England and Wales without electricity.
The Danish offshore wind developer said the project off Yorkshire, which is not yet completed but exporting power, “lost load” on Friday afternoon.
“We are investigating the cause, working closely with National Grid System Operator, which balances the UK’s electricity system,” said a spokesperson.
National Grid said the “root cause” of the wider system outage was the “almost simultaneous” loss of two large generators, the other being a gas-fired power plant, at 16.54 on Friday.
“We are working with the generators to understand what caused the generation to be lost,” said a statement on Twitter.
“Following the event, the other generators on the network responded to the loss by increasing their output as expected. However due to the scale of the generation losses this was not sufficient, and to protect the network and ensure restoration to normal operation could be completed as quickly as possible.”
Power was reconnected at 17.40.
“We appreciate the disruption caused and will continue to investigate, with the generators involved and wider stakeholders, to understand the lessons learnt,” added the statement.
Regulator Ofgem has requested an “urgent detailed report” from National Grid “so we can understand what went wrong and decide what further steps need to be taken”, which “could include enforcement action”.