Climate Change: How Heatwaves are Affecting Power Grids
Heatwaves have already struck a large number of countries in 2025, including China, the US, Canada, France and the UK.
The year so far is seeing near-record heat around the world, with Q1 being the second warmest on record.
Human-caused climate change has increased the frequency and intensity of heatwaves since the 1950s and is set to continue to do so according to the World Meteorological Organisation.
As temperatures continue to stay hot, power grids and markets are facing strain.
“Growth in global electricity demand this year and next is set to be among the fastest in the past two decades, highlighting the growing role of electricity in our economies as well as the impacts of severe heatwaves,” said Keisuke Sadamori, IEA Director of Energy Markets and Security, in the IEA’s July 2024 Electricity Mid-Year Update.
“It’s encouraging to see clean energy’s share of the electricity mix continuing to rise, but this needs to happen at a much faster rate to meet international energy and climate goals.
“At the same time, it’s crucial to expand and reinforce grids to provide citizens with secure and reliable electricity supply – and to implement higher energy efficiency standards to reduce the impacts of increased cooling demand on power systems.”
Electricity demand
Switching on a fan, air conditioner or cooling device uses electricity.
On hot days when many people do this at once, demand can spike and put the grid at risk of overloads and blackouts.
Thinktank Ember says that across China, the United States and India in 2024, heatwaves added tens of terawatt-hours to electricity demand during critical summer months.
It says that 37% of the increase in electricity demand in the US from April to September 2024, compared to the same period in 2023, was due to higher air cooling needs.
This led to an increase in coal and gas electricity generation to meet the higher demand.
“The solution is twofold: scale up efficient AC adoption to cut costs and ease peak demand, and invest in clean, flexible power to keep grids resilient as extreme weather intensifies,” said Kostantsa Rangelova, Global Electricity Analyst at Ember.
“The crisis is accelerating—our response must, too.”
Power generation
High temperatures can make power plants less efficient, particularly those that rely on water for cooling.
If cooling water is too warm or insufficient, some plants may have to reduce output or even shut down.
In Switzerland, a June heatwave caused Axpo’s Beznau nuclear power plant, cooled by water from the River Aare, to halve its output.
“The reduction in reactor output is a prescribed measure to protect the ecological balance of the Aare River," says Michael Kessler, Head of the Nuclear Energy Division at Axpo.
Renewable power generation is not exempt from the challenges heatwaves can bring.
CED Greentech, a US solar equipment supplier, says that hot temperatures can reduce the output efficiency of solar panels by 10-25%.
Equipment and transmission
Transmission lines and transformers can overheat, and prolonged exposure to extreme heat can degrade their performance, increase electrical resistance and even lead to failures or fires.
Hot weather can increase resistance in power lines, making it less efficient and more difficult to transmit electricity over long distances.
In overhead lines, for example, the UK Government identified that extreme temperatures can cause expansion, prevent efficient heat dissipation and affect tensile strength.
This combination of vulnerable infrastructure can cause widespread outages.
Blackouts during heatwaves can be particularly dangerous as not having access to cooling technologies can increase health risks.
Explore the latest edition of Sustainability Magazine and be part of the conversation at our global conference series, Sustainability LIVE.
Discover all our upcoming events and secure your tickets today.
Sustainability Magazine is a BizClik brand
