Heat wave and drought: What are the consequences on our electricity production?

At the beginning of summer 2025, a new heat wave is hitting France. With the Global warming, this phenomenon is increasing year after year. In France, since 1900, eight of the ten hottest summers have been recorded in the last decade. These episodes are increasing in frequency and intensity, accompanied by prolonged droughts.

If human bodies suffer, infrastructure is not spared. In particular, the heatwave is putting a strain on electrical networks and electricity production. During the summer of 2022, it caused repeated power cuts in Paris, Marseille, Toulouse or Nice.

Why are heatwaves and droughts threatening the supply of electricity and increasing its price on the market? What are the strategies deployed to strengthen the energy resilience of the electrical system? How can businesses anticipate these risks and protect themselves?

Let's take stock at the beginning of July, when the Météo France forecasts - announcing a hotter than normal summer - already seem to be coming true.

What is the impact of the heatwave on electrical networks?

Every summer, during heat waves, power cuts are observed on the network. If bodies suffer, so do equipment, especially as they have to deal with an increase in electricity consumption.

The effects of heat on electrical networks

Buried a few tens of centimeters under the scorching ground, Underground 20,000 volt electrical cables get hot. Under the effect of sudden temperature variations between day and night, some cables end up giving way, weakened by the alternation of dilations and retractions. Airlines are also subject to this phenomenon, which is a constraining RTE.

Other equipment in the electrical network may also stop working, overcome by overheating. Combinations for measuring the current and voltage of an electrical substation are the most affected, due to the elements that compose them. As explained by Enedis, “the insulating membrane becomes porous, water is formed, the porcelain explodes and the oil leaks.”

Airlines are also victims of forest fires, more violent during periods of heatwave and drought. In 2021, the line between Perpignan and Narbonne had to be de-energized, depriving more than 100,000 consumers of electricity.

Increased electricity consumption during a heatwave

Another constraint that weakens the electrical network during a heatwave: the sharp increase in electricity consumption in summer.

Revealing this trend, Monday, June 30, 2025, broke electricity consumption records, with a jump of 13% compared to the same date in 2024. In question? The increased use of air conditioning and fans, but also the increase in the needs of data centers and industry.

In 2022, RTE was already showing “the fans and air conditioning effect”. In summer, electricity accounts for up to a quarter of a home's electricity consumption. In its forecasts for summer 2024, RTE estimated its impact” between 700 and 1,100 MW per additional degree, depending on the temperature conditions encountered at the national level ”. In addition, there is the more intensive use of refrigerators and freezers, as well as artificial lighting during the day behind closed shutters.

What is the impact of the drought on electricity production?

While French electricity production and imports have always made it possible to meet the increase in summer electricity demand, the coming years are worrying with global warming. Because electricity production is also suffering from the heatwave and drought.

Nuclear production: a problem with the cooling of power plants

La nuclear production requires water to cool the reactors. It is collected and then released into nearby waterways. However, in times of drought, low water levels should be maintained for guarantee a minimum flow and protect the environment and biodiversity.

Also, legal restrictions impose keep river temperatures below maximum levels. It is fixed at 26°C for the Rhône and 28°C for the Garonne. However, the water rejected by Nuclear power plants Heats up the waterways. EDF is therefore forced to reduce the power of its power plants, or even to stop them, as soon as the threshold is exceeded.

These two requirements combined reduce nuclear production in summer. In a press release published at the end of June, EDF already announced possible restrictions on the production of its nuclear fleet starting in July. At the end of June, the first power plant was temporarily shut down in Tarn-et-Garonne (Golfech power plant).

Hydroelectricity: the drop in the water level

Due to the resource used, thehydropower is the first production to suffer from the drought.

While hydraulic production gradually recovered in 2023 and 2024, the year 2022 demonstrates the effects of drought on the drop in production. In August, it had fallen by 18% compared to the average observed since 2017, due to the 16% reduction in hydraulic stocks. In total, On the year 2022 particularly hot and dry, hydroelectric production stood at 46 TWh, i.e. 24% decrease compared to 2021.

A jewel of hydraulic energy and the largest artificial lake in France, Lac de Serre-Ponçon was partly dried up in the summer of 2022. The same is true for the lakes of Sainte-Croix and Castillon. Result: one 40% deficit in electricity production on the Alpine axis, normally contributing to 35% of electricity production in the Provence-Alpes-Côte d'Azur (PACA) region.

What are the impacts of the heatwave on other energy sources?

La Weak winds in an anticyclonic period reduces the Wind power generation. A study published in 2021 by the ORE agency (federation of French actors in the distribution of electricity and gas) shows thatDuring the summer period, wind power production decreases by an average of a third. It also turns out to be particularly unstable. Thus, in the summer of 2023, there were successive periods of high production at more than 15 MW and periods of lows at less than 1 MW. More generally, the wind deficit led to a 12.6% decrease in onshore wind production in 2024 compared to 2023.

Although less impacted, photovoltaic production is also affected by hot weather. Above 25°C, solar panels lose up to 0.5% efficiency per additional degree. In fact, the rise in temperature of solar cells causes a drop in voltage, which weakens the power of the panels.

What are the consequences of the heatwave on electricity prices?

The 2022 heatwave coincided with a historic rise in electricity prices. At the end of August 2022, prices were trading on the market at more than 1,000 euros per MWh. against 85 euros a year earlier. Although more moderate, this phenomenon was observed recently: in June 2025, the announcement by EDF of possible cuts in nuclear production immediately resulted in an increase in the spot price of electricity.

While, in a context of economic and geopolitical crisis, it remains difficult to quantify the influence of the heatwave on the rise in prices, it undeniably contributes to their volatility. Three mechanisms are combined:

• THEincreased production costs linked to the fall in domestic nuclear and hydroelectric production and to the increase in electricity imports.
• La tension between electricity supply and demand in Europe.
• The rise in the risk premium applied by market players to compensate for the lack of visibility on production.

These fluctuations impact the financial stability of businesses, whose cash flow is weakened by energy bills.

How to fight against the effects of drought and heatwaves on the electrical system?

Covered by imports, summer consumption peaks do not yet threaten France's security of energy supply today. But the expected increase in the frequency and intensity of heatwaves requires action to adapt the electrical system to a warmer world and to control electricity prices.

Strengthening the resilience of electrical networks

The managers of transport and distribution networks did not wait for the latest heat waves to initiate the adaptation of electrical networks. The 2003 heatwave was a trigger.

Launched in 2006, the Enedis “climate hazards” plan aims to replace and strengthen the most fragile underground and aerial networks. 30,000 kilometers of underground cables insulated with impregnated paper (CPI) must be replaced by 2040. In research and development, the manager is also making progress on cooling solutions for source stations and transformers.

For its part, RTE is studying a strategy for the accelerated adaptation of its airlines as part of its Ten-Year Network Development Plan (SDDR). Thanks to sensors, the transport manager can already redirect current to very high voltage lines cooled by the wind.

Innovating to maintain national electricity production

In his speech in March 2023 on the water plan, President Emmanuel Macron outlined the priorities to preserve resources. The first sector concerned with this necessary sobriety: electricity production.

With regard to the nuclear fleet, the President announced the commitment of a broad investment plan to replace open cooling circuits with closed ones. By reducing the dependence of nuclear power plants on water, this technology should ensure that nuclear production is maintained in summer. The State also relies on Construction of small modular SMR reactors, operating in a closed circuit. At the same time, EDF is focusing its research and development on improving the performance of power plant cooling systems, and in particular on air cooling towers.

In terms of hydroelectricity, the State relies on pumped energy transfer stations (STEP) to complete the French hydraulic park. La Multiannual Energy Programming (PPE) provides for the installation of a total power of 1.5 GW. Flexible and reactive, they contribute to the constitution of hydraulic stocks.

Diversifying and storing renewable energies

Continued diversification of production is essential in order to multiply electricity sources. Photovoltaic production, the biomethane Or the geothermal energy are reliable renewable production solutions that are not affected by high temperatures, drought and the absence of wind.

At the same time, France is making progress on energy storage to compensate for the intermittency of renewable energies and the decline in nuclear and hydroelectric production.

In particular, France is committed to: Thehydrogen. Presented as the “the most promising storage medium” in the hydrogen deployment plan, this energy vector is at the heart of several projects in France. Launched in March 2024 and coordinated by Storengy, the FRhyGe project aims, for example, to demonstrate the feasibility of storing, injecting and withdrawing 6,000 tonnes of hydrogen.

Easily operable, the Technology of vehicle-to-grid can complement more ambitious solutions. It consists in using electric vehicles to store electricity and discharge it onto the network during peak consumption.

Businesses: how to protect themselves from price volatility during a heatwave?

The rise in electricity prices during heatwaves is partly linked to the imbalance between supply and demand. If energy players can act on supply by increasing electricity production, consumers have the cards in hand to reduce demand.

Reduce power consumption

According to ADEME, 5% of buildings' electricity consumption is linked to air conditioning. The Energy Transition Agency recommends its reasoned use. Raising the set temperature from 22°C to 27°C halves the power consumption of air conditioners. Likewise, starting the air conditioning only from an outside temperature of 30°C, not 27°C, reduces energy consumption by three.

Other actions are simple and accessible to all, such as Cut off the day before computers, printers, and any electrical equipment, or Switch off the lights.

Adopt sustainable and efficient solutions

Of ecological alternative solutions and efficient ones make it possible to reduce the impact of air conditioners on electricity consumption.

In the form of an Evaporative Air Freshener (RAE), the bio-air conditioning offers a mobile, compact and economical solution for refreshing an office. The pose of solar films on the windows rejects up to 80% of solar energy. On the principle of Cool Roofing, of passive cooling techniques, such as reflective roofs or thermoregulatory paints, reduce the heat absorbed by the building.

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To conclude...

The heatwave and the drought are impacting the production and consumption of electricity. As a result, electricity prices are rising, due to increased demand and imports.

However, summer consumption peaks at 58 GW remain lower than winter peaks of more than 100 GW. France remains a country that is mainly an exporter. But while today electricity network managers remain confident about the security of electricity supply in summer, the resurgence of heat waves and periods of drought could upset this fragile balance.

It is urgent to prepare for the future in order to improve the energy resilience of the electrical system in the face of extreme weather events. Businesses can also anticipate by reducing their electricity consumption in summer.