The UK’s sweltering temperatures could cause chaos for power grids – leaving Brits at risk of blackouts this summer.
National Energy System Operator (Neso), which operates the electricity grid, warned that a surge in wildfires could plunge parts of the UK into darkness.
There has been a 600 per cent increase in the number of wildfires tearing through the UK over the last two years, according to the National Fire Chiefs Council.
These fires don’t just damage homes and wildlife; they also pose a serious threat to the pylons and transmission lines that make up the backbone of the grid.
Many of the UK’s 22,000 pylons and much of the 13,000 miles (21,000 km) of high–voltage transmission lines pass through upland areas that become a tinderbox in hot weather.
During intense heat, these cables sag and droop into the bone–dry vegetation below, sparking blazes and triggering widespread blackouts.
Deborah Petterson, Neso’s director of whole energy system resilience, told The Telegraph: ‘We can see that there might be more unexpected outages.
‘We very much focused on intense heat, followed by heavy rainfall and wildfire, because we’ve seen this very rapid change in the sort of physical aspects of climate that our industry hasn’t necessarily seen before.’
Experts warn that wildfires could cause blackouts this summer, as blazes damage the UK’s power grid. Pictured: The Daviot fire near Inverness, which caused blackouts in 2025
While energy pylons might look fire–resistant, they can actually be badly damaged by both smoke and flames.
When a pylon is engulfed in a plume of smoke or thick pollution, it can cause a phenomenon called flashover.
This is where carbon and ionised particles in the smoke allow electricity to arc to the ground like a bolt of lightning.
That sudden surge of power causes the grid’s safety systems to kick in, cutting off the power and causing local blackouts.
If the fire actually reaches the pylon itself, the situation can be even more dire.
Once temperatures reach a critical level, the heat begins to soften the aluminium cables, eventually causing them to sag or crack.
These failures cause significantly longer blackouts while time–consuming and costly repairs are made, typically costing £2.3 million per mile.
A Neso spokesperson told the Daily Mail: ‘Great Britain has a highly reliable and resilient electricity system. We are not expecting national critical infrastructure failures due to the hot weather.
Smoke from wildfires can trigger an effect called flashover, in which carbon particles allow an arc of electricity to jump to the ground. This causes safety systems to activate and power to cut off. Pictured: Pylons on a Scottish moor, which is highly at risk of wildfire
‘We are monitoring conditions closely and working with industry and government partners to keep the electricity system resilient. People should follow public health advice and continue to use electricity as normal.’
However, with the UK now facing one of the most intense heatwaves in recent history, there are now mounting concerns that wildfire–driven blackouts could become more common.
The Met Office has issued a rare red alert for extreme heat in central and southern England and parts of Wales for Wednesday and Thursday, when temperatures are expected to climb above 30°C.
As vegetation becomes drier and more prone to burn, the Met Office’s fire severity index now shows a ‘very high’ warning for areas surrounding Brighton, Southampton, Birmingham, Nottingham, and Sheffield.
That rating means that, if a fire were to start, it could spread faster than authorities can control and cause serious damage.
This has come alongside an intense thunderstorm over London and the West Country, which lit a house on fire in Bristol after a direct lightning strike.
While this week’s heatwave is exceptional, experts warn that the risk posed by wildfires will only become more severe in the future.
Professor Bill McGuire, an expert on climate hazards from University College London, says: ‘In the current climate, UK summer temperatures of 40°C plus will become possible, with heatwaves potentially lasting for multiple days at temperatures close to 40°C plus.
This comes as the Met Office issues a rare red warning for extreme heat, after forecasts predict temperatures reaching 38°C
This comes after the UK’s worst fire season on record. By October 2025, 46,907 hectares of land had been burned, compared to the previous record of 28,100 hectares in 2019
‘As 40°C plus temperatures become ever more common, expect many thousands sleeping in the streets as poorly insulated homes become uninhabitable heat traps, widespread power cuts as power cables sag and break, transport chaos as rails, overhead wires and signalling fail.’
This comes after 2025 became the worst year on record for wildfires in the UK, with the Global Wildfire Information System estimating that 47,026 hectares of land were burned in the first 11 months of the year.
That included the Daviot fire, which ignited south of Inverness and passed through overhead power lines, triggering widespread blackouts that left hundreds of rural homes without electricity.
Last year the Carrbridge and Dava Moor in the Scottish Highlands was devastated by the worst wildfire in living memory.
The blaze burned over 11,000 hectares (42.5 square miles) of forest and peatland, killing thousands of animals in its path – making it the UK’s first ‘mega fire’.
The Moorland Association warns that the one million hectares of heather uplands in the UK are particularly vulnerable to fires and are also home to thousands of vital pylons.
The group says: ‘Britain’s race to Net Zero depends on high–voltage overhead lines traversing our uplands. These lines don’t need to melt to fail – they just need smoke.
‘Preventing moorland fires is the only economically viable strategy for protecting our energy transmission network.’
HOW DO WILDFIRES AFFECT LOCAL TEMPERATURES?
Wildfire smoke lingering in the air can block out the sun enough to cause measurable temperature differences at the surface, even after the flames have died down.
Scientists say the interactions between smoke and the sun’s rays can either cool the air or warm it; when the rays are scattered, the air becomes cooler, while temperatures rise when the rays are absorbed.
Pictured, the San Francisco skyline is obscured by smoke and haze from wildfires behind Alcatraz on Nov. 14, 2018
A study published earlier this year found that the cooling effect can even extend to river and stream temperatures.
Brown carbon, in particular, has been found to have a significant effect, as it is more likely than black carbon to reach higher levels of the atmosphere, according to NASA.
But, the space agency explains, ‘as particulate matter in the atmosphere, both can interfere with solar radiation by absorbing and scattering the sun’s rays.’
Brown carbon is a major product of wildfires, as it’s created when grasses, wood, and other biological material burns.
‘Most of the brown carbon released into the air stays in the lower atmosphere, but we found that a fraction of it does get up into the upper atmosphere, where it has a disproportionately large effect on the planetary radiation balance – much stronger than if it was at the surface,’ Rodney Weber, a professor in Georgia Tech’s School of Earth & Atmospheric Sciences, said last year in a study on the phenomenon.
The graph above shows the amount of sunlight reflected by the landscape after a forest fire in North America (NA), Eurasia (EU), north east Eurasia (NEEU), southern Eurasia (SEU) and northwest Eurasia (NWEU)
Fires can also cause temperatures to drop by transforming the landscape, and increasing a property known as albedo – or the measure of light reflected by a surface.
As vegetation is destroyed in the fires, there is less foliage to absorb the sunlight and its warmth.
Studies in recent years have found that the resulting cooling effect can linger for years, particularly during the winter months.
