Emmanuel Rouges , Marlene Kretschmer, Theodore G Shepherd

Increasing the proportion of energy generation from renewables is one of the necessary steps towards reducing greenhouse gas emissions. However, renewable energy sources such as wind and solar are highly weather sensitive, leading to a challenge when balancing energy demand and energy production. Identifying periods of high shortfall, here defined as when demand exceeds production by renewables, and how these periods are affected by weather, is therefore critical. We use a previously constructed energy dataset derived from reanalysis data for a fixed energy system to analyse the link between weather regimes and periods of high shortfall during the boreal winter for 28 European countries. For each country we identify days with critical energy conditions, focusing on those with high energy demand, low production from wind and, solar, and high energy shortfall. Only a subset of the here considered six North Atlantic weather regimes are found to favour the occurrence of high shortfall days. In particular, blocking-type regimes affect large parts of Europe and multiple countries, suggesting that high shortfall days can occur across multiple countries simultaneously. Furthermore, if a subset of countries experience shortfall days, neighbouring countries have a higher likelihood of also experiencing shortfall days. The impact of the coldest winter of the 20th century in Europe as a potential worst-case scenario is examined. It is found that the persistent blocking conditions associated with that winter, if they occurred today, would lead to high demand and shortfall across most of Europe during most of the winter.