Whether you’ve heard of it or not, dunkelflaute (dunk el flout eh) is a challenge our energy systems will need to manage. The clean energy transition is posing lots of challenges for the power industry. The largest of these challenges is how to balance the electric transmission system and maintain reliability for a grid that’s dominated by weather dependent resources like wind and solar. After all, the sun never shines at night, and the wind never blows exactly when we need it.
Dunkelflaute is a German term that translates to Dark Doldrums or Dark Lull. In Australia, this has been referred to as a Renewable Drought.
As told earlier “Dunkelflaute” is a German term that refers to a period of winter weather with low light and little to no wind. This phenomenon is quite common in Northern Europe, occurring between 50 and 100 hours each November, December, and January; and affecting now worldwide due to global warming.
However, the Dunkelflaute phenomenon doesn’t necessarily have to hinder the progress of renewable energy. On the contrary, it could stimulate further research and innovation in the field. For instance, it could lead to the development of smart transformers across the grid, especially in areas mostly powered by renewables. These technologies would distribute energy according to in-the-moment needs, conserving power and preventing outages.
Moreover, Dunkelflaute-related concerns could also drive improvements in solar and wind technologies themselves. Some studies have already suggested the possibility of solar panels that work at night, and further research could make them a reality. Similarly, the need for more resilience could drive innovations in other alternative energy sources like nuclear and hydrogen power.
This phenomenon typically occurs in late autumn and winter months in Europe due to windless and cloudy conditions.
Dunkelflaute events can last more than two days over most of Europe and happen about every five years. To ensure power during such periods, flexible energy sources may be used, energy may be imported, and demand may be adjusted. For alternative energy sources, countries use fossil fuels (coal, oil, and natural gas), hydroelectricity or nuclear power, and less often, energy storage to prevent power outages.
Long-term solutions include designing electricity markets to incentivize clean flexible power. A group of countries is following on from Mission Innovation to work together to solve the problem in a clean, low-carbon way by 2030, including looking into carbon capture and storage and the hydrogen economy as possible parts of the solution.
EXAMPLE
For example, in January 2017, Germany experienced a dunkelflaute that lasted for 10 days, during which the wind and solar power output dropped to less than 5% of their installed capacity. This meant that Germany had to rely on other sources of energy, such as coal, gas, nuclear, hydro, and imports from neighboring countries, to meet its electricity needs
Dunkelflaute is a challenge for the transition to renewable energy, as it requires a flexible and resilient energy system that can balance the fluctuations of wind and solar power.
Some possible solutions include:
- Using other renewable energy sources that are more stable or controllable
- Increasing the interconnection of power grids across regions and countries
- Developing energy storage technologies, such as batteries, pumped hydro
- Implementing demand response and smart grid technologies
- Role of Energy Storage in Surviving Dunkelflaute
The Implications of Dunkelflaute
Dunkelflaute presents various implications for the energy sector. One of the key challenges is maintaining grid stability during periods of limited renewable energy supply. With a decrease in power generation from wind and solar, grid operators face the task of balancing supply and demand to ensure a reliable power supply to consumers.
- Grid Stability Challenges
Grid stability becomes a significant concern during Dunkelflaute. The strain on transmission networks increases as conventional power plants need to compensate for the reduced renewable energy supply. Frequency regulation also becomes more challenging, requiring grid operators to carefully manage the balance between supply and demand. - Balancing Supply and Demand
To address the challenges posed by Dunkelflaute, strategies and techniques are employed to balance the supply and demand of energy. Energy storage technologies play a vital role in this aspect, allowing excess energy to be stored for use during periods of low renewable supply. Battery storage systems, pumped hydro storage, and other innovative solutions help bridge the gap between generation and demand. - Decentralized Power Generation
Another approach to overcoming Dunkelflaute is through decentralized power generation. By utilizing microgrids and distributed energy resources, communities can become more self-reliant during periods of limited renewable supply. This reduces dependency on centralized renewable sources and enhances the resilience of the energy system. - Diversification of Renewable Sources
Diversifying the renewable energy mix is crucial in mitigating the impact of Dunkelflaute. By integrating different sources such as wind, solar, hydro, and geothermal, the reliance on a single source decreases. This diversification ensures a more consistent energy supply even during periods of low wind or solar irradiation.
