The new heatwave in France is curbing nuclear power generation in Europe's biggest nuclear electricity supplier and leading to spiking day-ahead power prices. France's day-ahead power prices soared by as much as 21.8% to $164.39 (142.5 euros) per megawatt hour (MWh) on Tuesday morning local time, per LSEG data cited by Reuters, as nuclear power generation is expected to be curbed at the mid-day peak on Wednesday. France has already had to resort to curbing nuclear power generation amid the prolonged and intense heatwaves this summer. In the middle of last month, France's nuclear power generation was slashed by 6.4 GW amid a prolonged and intense heatwave that hiked river temperatures and limited the ability of the power plants to use the water to cool reactors. The heatwaves have also affected nuclear power output in central and eastern Europe, where Hungary and Romania this month were forced to shut down reactors at their respective only nuclear power plants, due to the lowest water level of the Danube river in 90 years.