Great Britain’s electricity grid operator, the National Energy System Operator (NESO), issues a rare summer warning as a heatwave raises electricity demand and strains the power system. Multiple outlets report that NESO publishes a “margin notice” ahead of Wednesday evening, asking power plant owners to make any additional capacity available. The notice reflects concerns about the gap between expected demand and available supply, which NESO says is coming under pressure as temperatures rise. The warnings are linked to widespread use of cooling, including fans and air conditioning, as households respond to hotter weather. Bloomberg reports the warning is timed for Wednesday evening, while other sources describe it as a call-out that is uncommon for summer conditions. The Independent and Evening Standard note the heatwave is expected to bring record-breaking temperatures, increasing the likelihood of higher-than-usual electricity load. Overall, the reporting agrees that NESO seeks to protect system reliability by ensuring sufficient generation margin during peak demand caused by extreme temperatures.