The relentless heat this summer marked a “massive change” for Europe’s power systems. A surge in air conditioning use and a steep rise in electricity prices has begun causing blackouts alreadyread more

Europe’s energy networks have been pushed to their limits this summer as a succession of heatwaves drove up electricity demand and forced power plants to scale back operations.

June was the hottest on record in western Europe, leading to a surge in air conditioning use and a steep rise in electricity prices. Large parts of the region endured at least two intense spells of heat in June and July, with some areas facing more frequent extremes.

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According to industry body Eurelectric, total electricity demand in the EU jumped by 7.5 year on year during the peak of the June 23 to July 3 heatwave. Spain recorded a 16 per cent rise during the same period, when temperatures topped 40C, Financial Times reported.

At the same time, extreme heat forced several nuclear power plants to cut output or shut temporarily, while hydropower generation also faltered.

How is the pattern of demand changing?

The relentless heat this summer marked a “massive change” for Europe’s power systems, said Jan Rosenow, who leads the energy programme at Oxford university’s Environmental Change Institute.

Historically, peak demand in Europe has occurred in winter, but Rosenow warned that “summers get hotter at some point that might flip”. In early July, peak demand in Germany hit 1.5 terawatt hours – similar to its January average – while Spain’s demand during the heatwave exceeded its usual winter levels, according to data from the thinktank Ember.

Europe is heating faster than the global average, with scientists warning that extreme weather events, including heatwaves, are becoming more intense and prolonged as a result of climate change.

What has been the impact on power systems?

Some countries have already experienced dramatic effects. On 1 July, Florence and Bergamo were hit by major blackouts as Italy sweltered under a heatwave.

In Florence, hundreds of homes, shops, hotels and restaurants were left without power for hours as temperatures reached 40C. The outage, which lasted into the night, stranded people in lifts, forced the evacuation of a department store and led to widespread shop closures as card payment systems stopped working.

In Bergamo, officials had to bring in generators to restore limited power while repairs continued for several days.

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Kristian Ruby, secretary-general of Eurelectric, said grid operators faced a “tough reality” and “need to be prepared”.

SSE, the UK power company, reported that hydropower output fell 40 per cent in the quarter to the end of June as Britain grappled with heatwaves and drought.

Nuclear plants in France and Switzerland also reduced activity earlier in the summer as hotter weather made it harder to cool reactors. In France, 17 of the country’s 18 nuclear facilities were forced to cut capacity during the June-July heatwave, Ember said.

What are the longer-term risks?

Many inland nuclear plants rely on river water for cooling before releasing it back. With rivers already warm, operators were unable to discharge heated water without harming ecosystems. Similar concerns were raised for coal power plants, while falling water levels reduced barge capacity for transporting fuel.

When the EU’s multiannual budget for 2028 was unveiled in July, officials stressed that future energy assets and infrastructure must be “climate resilient by design” to withstand extreme weather.

Solar power offered some relief, with generation across Europe hitting a record in June, up 22 per cent from the previous year. Ember said this “kept the grid well supplied during daytime hours” in most areas.

“The surplus of solar energy during the day helped prevent blackouts. However, the use of energy storage is still insufficient, leading to reduced energy supply after sunset. This translated into a sharp increase in electricity prices,” said Pawel Czyzak, Ember’s Europe programme director.

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Electricity prices in late June doubled or even tripled, climbing above €400 per megawatt hour in Germany and €470/MWh in Poland.