Great Britain’s electricity system operator has stood down two coal-fired power stations that were put on emergency standby to keep the lights on amid a spell of cold weather. Earlier on Monday, National Grid’s electricity system operator (ESO) said the two “winter contingency coal units” would be available if required as temperatures dip below zero and demand soars. It said the public should continue to use energy as normal. But the units will not now be needed, with Great Britain’s energy needs met by other sources, including an anticipated pickup in wind power. The government this summer asked the owners of coal-fired power stations to slow closure plans as ministers looked to shore up energy supplies after the Russian invasion of Ukraine. Russia was previously a big supplier of natural gas to Europe, so the invasion roiled global energy markets and prompted a scramble for alternatives. The coal plants in North Yorkshire that were preparing to operate on Monday are owned by the energy company Drax. They would only operate if instructed to do so by National Grid, and Drax would not have been able to sell the electricity on the open market. A Drax spokesperson said: “National Grid ESO instructed the units to be warmed earlier today so that they were ready to generate power should the country require it. That instruction has since been stood down.” It comes as snowfall and ice caused travel disruption and forced school closures across the UK. The drop in temperatures prompted UK power prices to hit a record high on Sunday. Great Britain’s electricity generation system has rapidly moved away from coal in recent years: its first coal-free day was achieved in 2017, while in 2020 the island ran without coal-powered electricity for a month during a sunny May. The use of zero-carbon renewables has increased rapidly to replace it, but the UK has also increased its reliance on natural gas, a fossil fuel. That reliance has proved problematic during 2022 after Russia invaded Ukraine. Great Britain was heavily dependent on burning gas for electricity generation over the weekend, with low winds and cloudy skies. On Saturday, gas generated 62% of electricity in Great Britain, according to National Grid data. Nuclear power stations generated 14%, while wind and solar accounted for 8% and 1% respectively. Coal accounted for 4%. (Northern Ireland’s energy system operates separately.) National Grid ESO sought to emphasise that asking the coal-fired power stations to heat up did not mean it had any concern over blackouts on Monday. “This measure should give the public confidence in Monday’s energy supply,” National Grid ESO said. “The ESO as a prudent system operator has these tools for additional contingency to operate the network as normal and the public should continue to use energy as normal.” EDF, the French energy giant, said the nuclear fleet in the UK was running at full available capacity for the first time this winter after the return of Hartlepool Unit 1 from a planned refuelling outage. EDF operates the fleet, in which the British Gas owner, Centrica, is a minority investor. National Grid warned in October that severe conditions could trigger planned power cuts this winter. Fintan Slye, the executive director of the ESO, said that was still a possibility. But he told BBC Radio 4’s Today programme: “We remain cautiously optimistic through the winter that we will be able to manage it. We have enough supplies secured through the rest of the day that we can manage that and ensure there’s no disruption to customers’ supplies.” National Grid will run a test of its “demand flexibility scheme”, which encourages households to reduce their energy use during peak times, on Monday evening. Octopus Energy said its customers had been paid £1m for reducing their energy usage during the company’s first four “saving sessions” as part of the scheme. Customers saved on average more than £4 across the four sessions, with the top 5% of savers bringing in almost £20.