Vulnerability of European intermittent renewable energy supply to climate change and climate variability

The impact of both climate change and climate variability on the supply of intermittent renewable energy sources (I-RES) in Europe are assessed based on global climate model simulations. The main driver of climate variability over Europe is the North Atlantic Oscillation (NAO) in winter and its equivalent in summer (sNAO) which determine to a large extent the atmospheric circulation in Europe. Four climate scenarios are constructed distinguished by a moderate and strong increase of the average global surface temperature, and a positive and negative phase of the atmospheric variability over the North Atlantic and Europe. This spans a framework which combines the effects of both climate change and climate variability. Using a 2050 distribution of PV panels and wind turbines, we found that although climate change is likely to have significant impact on future I-RES output in Europe, its effects, especially for wind power, are outweighed by the high and strongly variable impact of the NAO/sNAO phases. Variability in the large-scale atmospheric circulation is able to induce median I-RES yield differences of 20-30% for high wind potential regions. Due to the NAO variability also months were identified with persistent calm conditions over Europe linked to the inflow of frigid arctic air resulting in some regions in a decrease in wind power of up to 75%a accompanied with an increase in heating degree days of up to 30%. The results of the study imply that if requirements for the power system including back up capacity take into account the weather variability, the power system can also cope with the climate change impacts.