Future evolution of compound low wind and cold events in winter impacting the French electricity system in CMIP6 climate models

With the expected rapid growth of renewables in the French power system, periods of prolonged low renewable energy generation are expected to have a greater impact on the power system, especially if compounded with high electricity demand. In particular, compound winter low wind and cold events are identified by the French electricity transmission system operator as events that can drive major risks to the future French power system. Using CMIP6 climate simulations, the scope of this study is to characterize the future changes of these climate compound events in the mid- and long-term and assess the associated uncertainties.

To identify compound low wind and cold events, a wind power capacity factor and an electricity demand indices are derived using near-surface wind speed and temperature data from CMIP6 models, including several Single Model Initial-condition Large Ensemble (SMILE), for the 1950-2099 period. Due to large differences between observed and modeled indices, bias adjustment is first applied to raw temperature and near-surface wind speed data. The benefit of multivariate bias adjustment over univariate methods is assessed.

First, we characterize the future changes of compound low wind and cold events frequency in the mid- and the long-term, and which of the marginal characteristics (i.e., cold or low wind events) primarily drive these changes. Then, we assess the associated uncertainties, including uncertainties from internal variability, climate models, emission scenarios, and bias correction methods. Finally, we identify the role of climate drivers, including the global warming level, and exposure drivers, including the installed wind power capacity and the electricity demand parameters. This work demonstrates the relevance of CMIP6 large ensemble of simulations and methodologies currently used in the compound weather and climate events community to assess future risks for the power system.