The heat of the past few days is driving electricity prices to their highest level in years. On the wholesale electricity market, 658.09 euros per megawatt-hour must now be paid. It has been since December 2022 that electricity has been this expensive. The most expensive time is around a quarter to nine and nine o’clock in the evening.
Solar panels generate the electricity needed to operate air conditioners during the day, but those revenues disappear in the evening. There is also little wind. It is therefore the gas power plants that supply us with electricity, and they are charging extra since they run very little during the day.
The pattern is called a ‘summer solar cliff’: During the sunny afternoon, solar production is substantial, and prices are far lower. Around sunset, solar output drops rapidly while cooling demand remains high.
‘Kühlkraftkrise’
In Belgium, hourly prices generally rise from around €77/MWh at noon to €579/MWh at eight o’clock in the evening. Prices surge most sharply between roughly 7 p.m. and 10:30 p.m., rather than at the hottest point of the day.
The combination of heat, running air conditioners, and declining renewable energy is called a ‘kühlkraftkrise’. It is the opposite of a ‘dunkelflaute’, a period in winter without revenue from renewable energy.
The same phenomenon in other countries
Consumers with a dynamic contract, particularly those with prices that vary by the hour or quarter hour, will see power peaks on their bills. In their case, it is best to schedule switching on high-consumption appliances (washing machine, dishwasher, car charging) for the morning.
In other countries, we see a similar phenomenon. There, electricity is also expensive in the evenings. The daily day-ahead averages are high across the region: Belgium €184.58/MWh, the Netherlands €175.96/MWh, Germany/Luxembourg €174.91/MWh, and France €136.12/MWh. Prices in France are significantly lower, thanks to the many nuclear power plants the country has.
Extreme temperatures
And it is not over yet, as even more extreme temperatures are expected in the coming days. For Brussels, the current forecast is 32°C on Tuesday, 36°C on Wednesday and Thursday, and 37°C on Friday. Temperatures in Paris are expected to rise to 40-41°C on Thursday, and Germany may also approach 40°C by Friday or Saturday.
This means that electricity prices will also maintain a low-to-high profile: moderate or even cheap at noon, with a higher risk of very expensive power, particularly around sunset. The biggest risk is a hot evening combined with weak wind, outages, limited import capacity, or – essential for Belgium – reduced French nuclear availability.
France exports electricity to Belgium, but the possibilities for doing so are not unlimited. Groupe Electricité de France (EDF) has already warned that high river temperatures could constrain output at several nuclear plants this week.
