Weather Shocks Challenge Europe’s Renewable Power Ambitions

A new study from Wood Mackenzie warns that Europe’s fast-paced move toward renewables is vulnerable to a rising threat: dunkelflaute. These prolonged periods of low wind and solar output, once considered rare, are now emerging as a systemic challenge for grid stability and energy economics—especially in northern markets with high wind capacity and limited geographic diversity.

On average, European markets experience 1.6 of these energy droughts each year, though the risk isn’t evenly distributed. Countries like Belgium see as many as three dunkelflaute events annually, while Portugal reports none. The difference lies in resource diversity: southern markets benefit from stronger winter solar output and more aligned peak demand patterns, easing the pressure on grid systems through storage and demand-side flexibility.

Timing matters, too. Nearly half of these low-generation periods last more than three days, with most occurring during the colder months of November through January—just as heating demand surges. This overlap is particularly problematic in northern Europe, where cold weather often arrives alongside low wind speeds. The result: soaring prices and a scramble for backup generation.

Matthew Campbell, Senior Research Analyst, European Power at Wood Mackenzie explains: "As Europe transitions to a power system dominated by variable wind and solar, understanding these extreme weather events is essential." 

New Economics for Dispatchable Generation Amid Scarcity Events

Dunkelflaute is a grid challenge that is rewriting the economics of electricity markets. Germany’s winter 2024 events offer a case in point. During two high-impact periods in November and December, intraday power prices spiked to $893/MWh. In fact, those two events alone accounted for more than half of the annual wholesale revenue for gas peaker plants (a type of power generation facility that operates during periods of high electricity demand, providing quick and flexible power to stabilize the energy grid).

Rather than steady baseload operation, profitability for flexible assets like gas and coal plants now hinges on being available during short windows of renewable shortfall. During a single November 2024 event, Germany relied on imports averaging 10.5 GW per day while also dramatically increasing thermal output to meet demand.

Wood Mackenzie projects that this dynamic will persist into the next decade. By 2030, thermal generators may still be required to meet up to 40% of demand during a single dunkelflaute period in Germany, with imports playing a larger role. Despite falling capacity factors, flexible fossil generation remains critical to system balance—and will continue to extract premium pricing during stress periods.