Great Britain's grid operator, the National Energy System Operator (Neso), has commissioned an independent legal firm to investigate allegations that its staff engaged in a cover-up regarding the risk of blackouts during the June heatwave. The accusations, raised in parliament by Conservative shadow minister Claire Coutinho, include claims that senior bosses prioritized protecting Neso's reputation over grid safety.
Whistleblower Allegations
A whistleblower alleged that control room staff were instructed not to leave a paper trail of key decisions made to stabilize the power system during record high temperatures in late June. Coutinho told parliament that staff were told to avoid keeping permanent records and that Neso's corporate affairs team pressured operators to make decisions to protect the organization's reputation. "If true, this is nothing short of a scandal," she said.
Industry data shows power grid frequency fell below operational limits as a high-pressure heat dome reduced renewable energy generation and caused unplanned outages at gas plants, while demand for air conditioning surged. The whistleblower claimed senior bosses ordered staff to ensure no audit trail existed for decisions related to managing frequency fluctuations.
Grid Performance During Heatwave
Neso stated that despite unprecedented conditions, the grid operated securely, with frequency and voltage within statutory limits. However, grid frequency slumped below Neso's operational limits of 49.8Hz to 50.2Hz for most of the period between 17:30 and 18:30 on 23 June. The lowest recorded frequency was 49.66Hz, still above the statutory lower limit of 49.5Hz set by government regulations.
The system operator raised the alarm over electricity supplies twice in the last week of June due to the heatwave's impact. It is estimated to have paid millions for a few hours of emergency electricity from gas power plants, a major source of carbon emissions.
Independent Investigation
Craig Dyke, a director at Neso, said a "full deep dive" into system operations would be undertaken. "Neso has commissioned an independent investigation into recent allegations around decision-making and record-keeping," he added. Both reports are expected to be published.
Political Reaction
Coutinho said whistleblowers approached her because they worried the grid is becoming increasingly unmanageable and lacked faith that their concerns were being taken seriously internally. The allegations have prompted scrutiny from the UK's data watchdog.
