Presentations

Abstract

The increasing integration of renewable energy sources poses significant challenges for grid stability due to the intermittency of renewable generation, particularly during periods of low wind and solar generation.  These periods of low wind speeds and solar radiation, termed Dunkelflaute (dark doldrums) in German, create supply shortfalls that must be compensated by dispatchable generation or storage, often at elevated costs. Due to the rapid emergence of wind and solar electricity generation in Germany, price peaks because of Dunkelflauten have increased recently.  This research aims to quantify how much surplus cost has been paid by the end-users as a result of Dunkelflauten, how long they usually last, how often they occurred, and how future occurrences could be predicted. To address these questions, a comprehensive web platform was developed to get a holistic view and provide novel insights into the effects of Dunkelflauten on electricity markets.  The methodology synthesizes aggregated weather data from Open-Meteo and market data from SMARD on https://DF-Insights.de. Furthermore, a simple approach to the measurement of weather influences was implemented, the Renewable Energy Potential Index (REPI). This method of quantifying and predicting variability in renewable energy was ranked against official forecasts and can be used to benchmark more advanced models to show the value of further processing steps. The system includes over 200 000 data points spanning 2018 to 2025 and features interactive visualisations.  The analysis identified 54 significant Dunkelflauten periods, with a maximum duration of 5 days (2022-12-08) and a maximum price increase during the Dunkelflauten time span of 194 €/MWh (2024-10-12), when setting the renewable share threshold to 30% of total electricity demand on quarter-hourly resolution and a minimum duration of 24 hours. The highest Dunkelflauten cost was also with the one that started on December 10, 2024, with 752,324,682 € additional electricity cost over a duration of 2.66 days.  One main highlight is the validation of a decrease in Dunkelflauten occurrences alongside an increase in build-up of PV and wind power plants.  This wide range of data visible not only provides energy planners with confidence for grid management and storage expansion but also contributes to improved renewable energy integration and reduced system costs.