Britain’s electricity grid operator has issued a request for increased power generation amid the country’s third heatwave of the year, citing concerns over tight electricity margins caused by extreme temperatures across Europe. The National Energy System Operator (Neso) announced the issuance of a so-called electricity margin notice beginning from the evening of July 9 as demand for electricity surged due to widespread use of cooling appliances such as fans and air conditioning.

This is the third time Neso has issued such a margin notice in 2026, a practice more commonly associated with winter months when electricity consumption rises as households heat their homes. However, the current heatwave has similarly placed pressure on the electricity system since high temperatures can reduce the efficiency of power generation methods including nuclear plants, gas stations, and water cooling systems.

Neso emphasized that the notice signals a desire for a larger safety margin between electricity supply and demand rather than an immediate risk of blackouts or inadequate generation capacity. A spokesperson explained that forecasts indicated narrow margins during peak usage periods, influenced by the ongoing extreme heat which reduces the availability of some power sources. The margin notice serves as a measure to allow increased production if necessary to maintain grid stability.

The grid operator reiterated that it would continue to monitor conditions closely and take actions as required to secure electricity supplies. Earlier this year, Neso issued similar requests for additional generation capacity in June, both of which were withdrawn before implementation, demonstrating confidence in the overall supply situation.

The heatwave has prompted health and fire warnings across the United Kingdom, with temperatures expected to reach well above 30 degrees Celsius in many regions and peak near 36 degrees Celsius in parts of England. The Met Office forecasts that this extreme heat will persist through Friday, contributing further to the high demand for electricity as residents and businesses seek relief from the soaring temperatures.