Rising temperatures across Europe are driving electricity prices to significant peaks during evening hours, as grid reliance shifts away from solar power. When photovoltaic generation drops off at sunset, the resulting supply gap often forces market prices to climb, a phenomenon currently exacerbated by sustained heatwaves that increase cooling demand across the continent.
According to data from the European Network of Transmission System Operators for Electricity (ENTSO-E), the correlation between high temperatures and electricity price volatility has become more pronounced as the share of variable renewable energy in the European mix increases. This trend is particularly evident in the “dusk effect,” where the rapid decline of solar output coincides with the evening peak in residential and commercial energy consumption.
The Mechanics of Price Volatility During Heatwaves
The fundamental driver of these price fluctuations is the intermittency of solar energy. As solar panels cease production in the late afternoon and early evening, grid operators must compensate by ramping up dispatchable power sources, such as natural gas or pumped-storage hydropower. When heatwaves persist, the demand for air conditioning remains high well into the evening, creating a supply-demand imbalance.
The International Energy Agency (IEA) notes that electricity markets are increasingly sensitive to weather-related supply constraints. In periods of extreme heat, not only does demand rise, but the efficiency of thermal power plants can decrease if cooling water temperatures become too high, further tightening supply margins and putting upward pressure on wholesale prices.
Impact on European Energy Markets
Market analysts observe that these evening price spikes are not merely a function of supply but also of market design. In many European regions, the last unit of electricity required to balance the grid—often a gas-fired power plant—sets the clearing price for the entire market. Consequently, when solar output vanishes and demand is high, the marginal cost of production rises sharply.
The European Union Agency for the Cooperation of Energy Regulators (ACER) has highlighted that price volatility is a natural feature of a power system transitioning to net-zero, though extreme weather events amplify these swings. Consumers and industrial users are increasingly exposed to these short-term price signals, leading to higher average costs during the summer months when heatwaves are more frequent.
Strategies for Grid Stability
To mitigate the impact of solar-related evening price peaks, energy experts point to the necessity of flexible grid assets. Battery energy storage systems (BESS) are increasingly being deployed to “shift” solar energy generated during the day to the evening peak. According to a report by Ember, a climate and energy think tank, the rollout of utility-scale battery storage is a critical component in stabilizing prices as solar capacity grows.
Beyond storage, demand-side management plays a vital role. By incentivizing industrial consumers to shift energy-intensive processes to periods of high solar availability, grid operators can reduce the pressure on the system during the critical sunset hours. This requires real-time data integration and a regulatory environment that rewards flexibility.
Looking Ahead: Market Resilience
The next major checkpoint for European energy markets will be the publication of seasonal outlooks by ENTSO-E, which assess the adequacy of power supply for the upcoming winter. These reports provide a baseline for understanding how current summer stressors, such as reservoir levels for hydropower and gas storage volumes, will influence market stability later in the year.
As the energy transition continues, the reliance on weather-dependent generation will necessitate continued investment in grid infrastructure and cross-border interconnectors. These projects allow regions with excess renewable energy to export power to areas facing shortages, effectively smoothing out price peaks across the continent.
Have you noticed changes in your energy costs during recent heatwaves? Share your thoughts and local experiences in the comments below.