The National Energy System Operator in Great Britain mobilized emergency measures to secure additional power supplies as an intense heatwave created strain on the energy system. The operator issued a notice late on Tuesday requesting generators to provide extra electricity to meet anticipated demand as households increased consumption of air conditioning and electric fans during peak evening hours. The operator initially sought an additional 1,900 megawatts of power to maintain supplies within normal safety margins during the evening peak between 7pm and 10pm. After securing commitments for approximately 1.7 gigawatts of imported electricity from continental Europe, the operator cancelled the notice on Wednesday afternoon. The arrangement cost roughly £1,400 per megawatt-hour, substantially higher than typical market pricing and nearly 20 times the average rate recorded in the previous June. The heatwave conditions gripped much of Europe and created cascading effects across the continent’s energy systems. An area of high pressure trapped heat over the region while simultaneously reducing wind speeds, thereby limiting renewable energy generation. Additional complications arose from lower output at some nuclear facilities in France, where elevated river water temperatures complicated cooling operations. The combination of surging demand and constrained supply pushed electricity prices across European markets to multiyear highs. The extreme temperatures also disrupted broader aspects of British infrastructure and daily life. The nation recorded its highest-ever temperature for the month of June, with 35.8 degrees Celsius measured in West Sussex. Train operators advised passengers to limit travel, educational facilities across southern regions remained closed, and hospital services were disrupted. Union organizations called for strike action on the hottest day, while discussions continued regarding workplace temperature protections.