A comprehensive new study by Wood Mackenzie reveals the growing challenge of "dunkelflaute" – prolonged periods of low wind and solar generation – as Europe transitions to renewable-dominated power systems. Published on July 31, 2025, the research highlights how these events are driving extreme price volatility and exposing critical vulnerabilities in energy security across the continent, particularly following notable occurrences in November and December 2024.
The report, titled “Weathering the lulls: the risks and opportunities of dunkelflaute,” indicates that European markets will, on average, experience 1.6 "dunkelflaute" events annually, though significant regional disparities exist. Northern markets, heavily reliant on offshore wind, face the greatest exposure due to correlated wind fleets and limited spatial diversity. Conversely, Southern European markets exhibit less "dunkelflaute" risk, as robust midday solar generation, even in winter, aligns more closely with peak demand and facilitates effective load shifting via battery storage. For instance, Belgium records the highest frequency with three events per year, while Portugal experiences none. These events are most prevalent between November and January, with 41% lasting longer than three days.
The market consequences of "dunkelflaute" are severe, ranging from extreme prices to dramatic shifts in the power supply mix. In Germany, wholesale revenues generated by gas peaker plants during just two "dunkelflaute" events in 2024 exceeded 50% of their annual total. During the November 2024 event, German intraday prices surged to €820/MWh. This necessitated a dramatic ramp-up in gas and coal generation, with German imports averaging 10.5 GW over three days to meet demand.
Matthew Campbell, Senior Research Analyst, European Power at Wood Mackenzie, emphasized, "As Europe transitions to a power system dominated by variable wind and solar, understanding these extreme weather events is essential." The study identifies three primary drivers of "dunkelflaute" frequency: wind resource distribution, particularly geographic concentration; solar irradiance levels, especially winter availability in northern markets; and supply-demand synchronicity, or the misalignment between renewable generation and peak demand.
Campbell further noted, “Our research shows that scarcity events will increasingly drive dispatchable asset revenues, with the business case for new flexible generation hinging on revenue opportunities during limited low-renewable periods each year.” He added, “Despite declining utilisation rates, gas-fired generation remains system-critical, emphasizing its increasing value across many European markets.” Looking ahead to 2030, Wood Mackenzie's analysis for Germany projects that during "dunkelflaute" periods, thermal generation will remain indispensable, with gas and coal supplying 40% of the load in Europe's largest market and net imports potentially exceeding 20 GW during a single event. Policymakers are urged to prioritize spatial diversification in energy policy and planning frameworks, especially in high-exposure markets, as the coldest days are disproportionately linked to low wind output, heightening supply risks during peak demand. This underscores the critical need for targeted capacity mechanisms in market design.