Britain’s effort to avoid blackouts hinges on a control centre in Berkshire, where engineers balance supply and demand second‑by‑second. Neso’s Julian Leslie called the task “more complex than flying an airplane.”

During a June heatwave, a surge in evening demand forced Britain to cut exports to the Netherlands and triggered an emergency call for extra generation. Data from Montel showed the system frequency fell below the operational limit of 49.8Hz for almost two hours, with the longest breach lasting 26 minutes.

Conservative shadow energy secretary Claire Coutinho alleged operational decisions were made without audit trails and that corporate affairs interfered. Neso denied the claims and commissioned a review by Eversheds Sutherland.

The shift to renewables has removed the inertia once provided by coal and gas turbines. Neso is lowering minimum inertia to 102 GVAs, expecting to save £96mn a year, though EDF and EP UK Investments warned of stability risks. Ofgem approved the change after a review by Professor Keith Bell.