UK grid operator issues third electricity margin warning

Britain's National Energy System Operator (NESO) has issued its third electricity margin warning of the summer, forecasting a tight supply period for Thursday evening as a severe heatwave strains power grids across northwestern Europe. The notice, covering the peak demand hours from 6:30 p.m. to 10:30 p.m., calls on energy companies to make additional generation available to cover a projected shortfall.

The operator stated the warning is due to extreme temperatures across the continent reducing the availability of some generation and is not an indication of imminent blackouts. Historically, such margin notices were associated with winter heating demand, but their repeated issuance this summer signals a shift in seasonal pressure on the grid. The current heatwave, the third of the year, has pushed temperatures in parts of England toward 36 degrees Celsius, increasing demand for cooling from fans and air conditioning while simultaneously hampering supply.

A key factor is the significant reduction in wind power output due to calm conditions, with one report noting wind contributed just 6.6 percent of the electricity mix on Wednesday. This has increased reliance on other sources,...