Blame it on the sunshine

When the frequency broke on 23 June, demand was running above NESO's forecast. Air conditioning and AI cooling were blamed — five summers of settlement data show where that heat-driven load lives, and how demand can be shadowed by sunshine.

On 23 June, with temperatures at 34.6 °C, Britain's grid had its most uncomfortable evening in years. From eight in the morning actual demand ran above NESO's forecast; by late afternoon the error exceeded 1,500 MW — more than the 1,400 MW of reserve the operator is obliged to hold against the loss of its single largest infeed. Between 18:51 and 20:03 t…