Heatwave on Europe: the impact of a "Hitzeflaute"
As a heat wave has engulfed Europe, there is a new sexy word in the European energy world: Hitzeflaute1, which is an updated version of the Dunkelflaute2, but for a hot summer day. Let’s discover together the impact of the heatwave on the European power markets!
The recent heatwave
Europe has experienced a serious heatwave with Paris reaching 40 degrees on Tuesday 1 July.
Unsurprisingly, the heatwave has directly impacted electricity spot prices due to the following reasons (not exhaustive):
Increased Demand: The primary cause is the heightened demand for air conditioning. With a growing number of heat pumps, European power demand is likely to be increasingly affected by high temperatures. Additionally, demand remains relatively high for air conditioning in the evening when solar generation is low.
Reduced Power Plant Output: Some power plants cannot operate at maximum capacity during extreme heat, and others may be unable to run due to environmental constraints, such as excessively high cooling water temperatures (in rivers).
Scheduled Maintenance: Several power plants have annual maintenance planned for the summer months, as demand is generally lower.
In these conditions, with minimal renewable generation available, including wind, day-ahead prices surged to 517.57 €/MWh in Belgium and the Netherlands, followed by Germany and Denmark at 476.19 €/MWh at 8 PM on July 1st.
Dunkelflaute vs Hitzeflaute
Such a situation of high demand and low renewables happen generally in the winter, in the so-called Dunkelfalute period. Hereunder are the graphs of the day-ahead price, the renewable generation, and the residual load in Belgium for the 12 December 2024 and the 1 July 2025.
There are obvious differences between these two days:
The residual load stays high most of the day during a Dunkelflaute day, reflecting the fact that virtually no renewable is present. During a Hitzeflaute, this is very different as solar generation is reaching confortable level.
The market prices stay high for the red curve (12 consecutive hours above 300 €/MWh), while the yellow curve shows only a relatively peak (only 4 hours above 300 €/MWh).