French shopkeepers are now expected to keep their doors shut while their air conditioning is turned on, Agnes Pannier-Runacher, France’s minister of ecological transition, announced on Sunday.

Having air conditioning on with doors open could lead to “20% more consumption,” Runacher told French RMC Radio, adding that such a situation would be “absurd” given the current tight energy supply in Europe.

French businesses will also have to cut back on their use of illuminated signs and advertising, Runacher said in another interview with French weekly newspaper Journal du Dimanche on Sunday. 

French energy rationing

Runacher added that two separate decrees would be issued “in the coming days” that would address the use of air conditioning and illuminated lighting, the latter of which will be limited between 1 am and 6 am across the country with the exception of airports and train stations.

While speaking with RMC, Runacher cautioned that businesses who do not comply with these rulings would create “unfair disadvantages” for their competition, and so would be liable to be fined up to 750 euros ($767) if they fail to limit electricity use through the new measures.

French businesses were already preparing to lower their electricity usage this year as spiking energy prices and a shortfall in natural gas supply from Russia sparked fears of energy rationing in Europe. 

Last week, a joint statement by a federation of French supermarket chains announced that they would begin switching off their signs outside of opening hours, cutting back on light usage, and managing air conditioning and heating systems in stores more conservatively.

These measures were expected to begin on October 15th, although Runacher’s latest statements may bring the changes forward. 

Air conditioning in stores has been a primary target of energy rationing recommendations in France and Europe. In France, as in other countries in Europe, air conditioning is relatively rare in homes, with fewer than five percent of French households having access to it.

But artificial cooling in commercial spaces is much more common. A 2020 report by the French agency for ecological transition found that 55% of French stores and 64% of offices possess air conditioning systems which are becoming increasingly important lifelines as France battles through record-high temperatures amid this summer’s European heatwave.

Heatwave batters European energy

Runacher warns that the higher usage of air conditioning during the heatwave is contributing to spiking electricity demand at the worst possible time. Last week, France hit a record-high baseload electricity price of 645 euros per megawatt hour, meaning that electricity demand is beginning to eclipse supply in the country.

France is not as reliant on natural gas for its electricity generation as other European countries, such as Germany. But output from the main source of electricity generation in France—nuclear energy, which accounts for around 70% of the country’s power—has been severely hit by the heatwave.

Around half of France’s atomic fleet has been taken offline this month due to the high temperatures, as the heatwave has warmed the freshwater sources normally used as a coolant in nuclear power plants.

Less water to use as coolant has pushed plants to either pause operations or significantly reduce electricity output.

The energy shortfall has pushed France—which has historically been Europe’s top energy exporter—to rely on nations whose power grids are more focused on natural gas and renewables such as Britain to satisfy its energy needs.