What is Dunkelflaute?

Dunkelflaute is a German term that translates as “dark lull”. It’s been gaining popularity online at the start of a potentially tricky winter for Europeans.

Some experts fear that a ‘dunkelflaute’ event, characterised by inadequate sunshine and low wind speeds, threatens to aggravate the energy crisis in Europe by hampering renewable energy production.

Here, we take a look at the dunkelflaute definition and why the term is trending.

Key points

What is dunkelflaute?

Dunkelflaute is a meteorological phenomenon when there is little to no renewable energy power generation due to unfavourable weather conditions.

Dunkelflaute typically occurs in late autumn and winter months in Europe due to windless and cloudy conditions. It is a German term that translates to “dark doldrums” or “dark lull”.

“The weather phenomenon of the cold, dark doldrums often occurs in late autumn and winter when there is no wind and cloudy autumn or winter weather for several days or weeks. At the same time, the demand for electricity is above average due to very cold temperatures,” explained Germany-based renewable energy publication energie-experten.org.

History of dunkelflautes explained

Europe has led the world when it comes to the green energy transition. In 2019, the European Union (EU) introduced the European Green Deal, which set the goal of making Europe the first “climate neutral continent” by 2050.

The renewable energy sector became the lynchpin of this ambitious plan as 27 EU member states pledged to reduce emissions by at least 55% by 2030. The EU also set a target for renewable energy sources to contribute 40% of the EU's energy mix by 2030.  

The EU’s energy dependence on renewable energy sources, especially solar and wind, has been on the rise over the past decades. According to Eurostat, the share of energy consumption from renewable power for the EU more than doubled from 9.6% in 2004 to 22.1% by 2020.

Solar contributed over 5% of the EU’s total electricity production in 2020 and was the fastest-growing energy source in the region. Wind power accounted for more than one-third of the EU's renewable power generation in 2020.

The increased renewable power share has made Europe vulnerable to weather-induced phenomena, such as a dunkelflaute.

Historical studies showed numerous examples of dunkelflautes. According to Germany-based energy market consulting services firm Energy Brainpool, Europe saw a minimum two-weeks of dunkelflautes every other year between 2006 and 2016.

A research publication by the Delft University of Technology stated that dunkelflaute events occurred during the months of November, December and January in most European nations.

The report added that about 50 to 100 hours of dunkelflautes occurred in each of those three months a year across Europe. The possibility of simultaneous dunkelflaute events occurring in neighbouring countries was as high as 30% to 40%, said the university. 

Unfavourable weather conditions for solar and wind power generation are not rare. 

What does a dunkelflaute mean for Europe?

Europe entered the winter of 2022 during challenging conditions. Restrictions on Russian energy imports, elevated fuel prices and decommissioned nuclear power plants have threatened the energy security of the region.

European authorities have to now monitor an additional threat in the form of dunkelflautes this winter.

In the event that prolonged weather conditions limit solar and wind power generation, power grid operators will be forced to use fossil fuels, like natural gas, to cover the shortfall.

According to energie-experten.org, batteries and load management provide short to medium-term options when dealing with dunkelflautes. However, additional power generation capabilities and energy sources are necessary to secure energy supplies.

How can Europe overcome dunkelflaute?

Experts have pointed to the EU’s inter-connected power grid system to tackle dunkelflaute-induced shortfalls in energy supply. 

• Cross-border electricity

Over the years, EU authorities have placed great importance on improving the region’s cross-border electricity interconnections. The European Commission noted:

Authorities have set a target for its member states to allow at least 15% of the electricity produced in a country to be transported to neighbouring countries by 2030.

• Backup energy sources

For the short-term, power operators may be required to hold backup energy sources such as natural gas or hydrogen, which may come at additional storage costs to counter weather-dependent events.

• Battery technology

Over the longer term, advancements in battery technology will ensure efficient storage of surplus renewable energy that can be used when needed. 

More importantly, well-constructed government frameworks that lower barriers for renewable energy investments and the promotion of a collected pan-European effort are needed to tackle weather-dependent hurdles in the renewable energy sector.

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