Meteorological drivers of co-occurring renewable energy droughts in Europe

As Europe transitions to renewable energy sources, its electricity system becomes increasingly dependent on weather conditions. This reliance introduces new challenges for energy security, as periods of high electricity demand may coincide with low renewable energy production (energy droughts). Weather conditions driving such energy droughts transcend national boundaries, potentially causing widespread energy stress across Europe. Existing studies have explored such energy droughts, but they have primarily focused on moderate cases or utilized historical reanalysis data, which limits the ability to assess the full range of variability and extreme impacts from different meteorological conditions. This study addresses these limitations by using 1600 years of simulated meteorological data to model country-level renewable electricity production (solar PV, wind power, and run-of-river hydropower) and demand across Europe. We identify clusters of countries that frequently experience simultaneous 7-day energy droughts and analyze how different large-scale weather regimes influence these co-occurrence patterns. Our results show that the North Atlantic Oscillation (NAO) negative phase and Blocking weather regimes pose the highest risk of co-occurring energy droughts, though their impacts vary by region. For example, northern Europe faces a doubling of drought risk under NAO negative, while Iberia sees reduced risk. Blocking has the opposite effect on these regions. Despite the potential for international electricity transmission to mitigate energy stress in certain areas, our results suggest that energy droughts often span large areas. This highlights the need for robust backup solutions to address renewable energy intermittency.