Inside Dunkelflaute, Europe's Renewable Energy Challenge

When it is windy, turbines can turn it into wind energy.
When it is sunny, solar panels can create energy from the sun’s rays.
So the phenomena of Dunkelflaute, characterised by periods when there is minimal or no wind and solar power generation, poses significant challenges to Europe's energy landscape.
This is particularly pronounced during colder spates, frequently observed across the continent primarily during winter seasons, with durations lasting from several days to weeks.
Understanding Dunkelflaute
The Oxford Institute for Energy Studies clarifies the concept of Dunkelflaute, highlighting its growing frequency. A report authored by Anouk Honoré and Jack Sharples highlights that Dunkelflaute directly impacts gas demand volatility and pricing, especially during market tightness.
The paper says: “As renewable generation grows its share of European power generation, the impact of these episodes has been to drive up the volatility of gas demand and influence prices — particularly at times of tightness in the market — when gas-fired power is despatched to fill that intermittency gap, even though the total gas demand in power continues to fall as the renewables build-out continues."
This reliance becomes pronounced during Dunkelflaute coinciding with cold snaps.
During such periods, the already winter-peaking systems in Europe face additional strain trying to balance demands for heating and power.
Moreover, the evolving dynamics in the energy sector, marked by higher nuclear generation and renewable outputs, have shifted the operational preference away from fossil fuels, relegating gas plants to more of a secondary, backup role. Still, while renewables like wind are expanding, their unpredictable nature leads to further complexities in predicting and managing gas demand peaks, adding layers of uncertainty to an already complex grid management task.
“Gas demand in Europe displays strong seasonality and sudden and short-term spikes are normal during winter,” the report states.
“But the growth of wind generation brings another layer of uncertainty, with additional peaks in gas demand, for which size and duration are harder to predict.
“With limited short-term flexibility on the demand side — for now, this should improve in the future — flexible and rapidly available gas supply will be increasingly crucial to balance the system in Europe.”
Key insights from the Dunkelflaute study
The intermittent nature of renewables necessitates a strong backup in the form of gas-fired power plants to maintain a stable energy supply. Dunkelflaute events, when aligned with colder climates, amplify the need for gas due to escalated heating demands.
From the Oxford Institute for Energy Studies' analysis, several critical takeaways arise:
- Gas-fired power plants remain the primary source of flexibility in Europe's power system: They are crucial for managing the fluctuating outputs from wind energy sources.
- The growing share of wind power in the energy mix introduces unpredictable peaks in gas demand: Foreseeing the magnitude and duration of these spikes becomes increasingly challenging.
- The power sector's relationship with gas demand has transformed: What once was a source of short-term flexibility has now evolved into a sector marked by volatility and unpredictability, though it has also grown more immune to high gas prices.
- Reduced demand-side flexibility implies a need for more adaptive supply-side strategies: This is primarily facilitated by gas storage and imports of liquefied natural gas (LNG).
“We need more clean firm generation, storage, grid infrastructure, demand response, et cetera, to tame Dunkelflaute — and today’s gas market has risen to the challenge,” says Brian Marrs, Senior Director, Energy Markets at Microsoft.
“But gas-electric planning must continue to embrace seasonal gas flexibility to match weather-driven seasonality in GWs of generation. I.e. the power system needs to re-size to the weather.”
Industry perspectives on Dunkelflaute
“When there is no wind, we get high electricity prices with this failed electricity system,” Ebba Busch, Deputy Prime Minister of Sweden, Minister for Energy and the Minister for Business and Industry, says.
“Germany’s energy system isn’t right.
“It is a result of decommissioned nuclear power. When it’s not windy, we get high electricity prices.”
She argues that if Germany was able to produce more electricity for the European network, prices would lower for all.
Amund Vik, Senior Advisor to Eurasia Group, adds on the subject: “The European energy system needs integration to be secure, as you do the energy transition.”
Gerald Kaendler, Director Asset Management at Amprion says: “Dunkelflaute is the worst case scenario for a renewables-based power system.
“There will be times when not enough wind and solar power is available.”
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