Britain is set to experience a significant drop in solar energy output next Wednesday due to a solar eclipse, prompting the National Energy System Operator (Neso) to increase reliance on gas-fired power plants to maintain grid stability. The eclipse, expected to be the largest visible in the UK since 1999, will cause solar generation to fall by as much as 1.3 gigawatts (GW), a reduction comparable to the output of two nuclear reactors.
The eclipse will take place between 6 p.m. and 8 p.m., with the moon obscuring up to 95 percent of the sun's light. The most pronounced effects are anticipated in western regions of Britain, including Wales, Devon, and Cornwall, where solar generation is expected to experience the steepest declines. The reduction may range from approximately 0.7 GW to 1.3 GW, depending on weather conditions in the hours leading up to the event. On sunny days, solar power can contribute up to 16 GW to the UK’s energy mix.
Neso officials have been monitoring the eclipse's potential impact on embedded solar generation for about a year. According to a Neso analyst, the geographic scope of the eclipse’s influence extends across Europe and reaches as far as the United States. While fluctuations in power output can risk destabilizing the grid, the system operator has prepared contingency measures, including ramping up gas-fired plants and utilizing battery storage, to manage the anticipated drop.
The timing of the eclipse during early evening hours means the reduction in solar energy will be less severe than if it had occurred at peak midday sunlight. Nonetheless, energy producers have been instructed to maintain additional generating capacity as a precautionary measure.
Neso emphasized that the eclipse is a predictable occurrence that has been accounted for in operational planning well in advance. A spokesman noted that the UK electricity system is engineered to handle daily variations in energy generation, and market participants are able to adapt their strategies accordingly. Neso will continue its standard operational procedures to ensure supply and demand remain balanced during the event.
The operator has recently faced scrutiny unrelated to the eclipse, including allegations of a cover-up regarding power outage risks during June’s heatwave and criticism over management of the renewable energy connection queue. Neso has engaged an independent law firm to investigate claims involving staff instructed not to document grid stabilization attempts. Despite these challenges, Neso maintains that the anticipated reduction in solar output caused by the eclipse is well within the system’s capability to manage without disruption.