Global risks of renewable energy droughts under climate change

Addressing climate change and reducing greenhouse gas emissions requires integrating variable renewable energy sources, such as solar and wind, into national energy systems. However, periods of compounding low wind and solar potential, known as energy droughts or ‘Dunkelflaute’ conditions, present significant challenges for electricity grids. While some regional studies on energy droughts exist, there is no comprehensive global assessment of how future climate changes might affect these events.
Using temperature, radiation and wind projections from 13 global climate models, energy droughts are analyzed for the 1979-2100 period using coincidence threshold analysis for their detection (10th percentile of the marginal distributions of wind and solar potential). Our analysis reveals that for most regions of the world, the frequency and duration of energy droughts are projected to increase with rising levels of warming. For instance in India and in the Sahel region, the risk of compounding low wind and solar potential is twice as high in 2100 under the RCP8.5 scenario than during the 2000-2020 period.
We also show how different strategies of balancing solar and wind capacity such as minimizing the variance of the production instead of maximizing the mean can affect vulnerability to compound shocks; in some countries optimizing this balance could substantially decrease the frequency of compound energy droughts. We note that in some regions the risk of compound wind/solar energy droughts remains high regardless of the energy mix. This underscores the importance of adapting energy strategies to mitigate the risks of increasing energy droughts under future climate conditions.
This study emphasizes the need for a comprehensive approach to optimally align short-term mitigation goals with the long-term impacts of climate change.