The National Grid has warned of a potential electricity supply shortfall in Great Britain this Wednesday evening. The alert comes as a near-total solar eclipse is set to obscure up to 95% of the sun, significantly impacting the nation's solar energy output. Estimates suggest that between 300 megawatts (MW) and 1,100MW of solar power could be lost during the event.

The timing of the eclipse presents a particular challenge for grid operators, as it coincides with the fifth heatwave of the summer. This weather pattern has already driven up electricity demand as residents and businesses increase their use of air conditioning and cooling systems. The combination of reduced renewable generation and heightened consumption has prompted the grid operator to raise an official alarm to ensure system stability. While the grid is designed to handle fluctuations, the scale of this eclipse—the most significant visible in Great Britain since 1999—requires careful management to prevent supply gaps.