Review of model-based electricity system transition scenarios: An analysis for Switzerland, Germany, France, and Italy

Policymakers currently face the challenge of supporting a suitable technology mix to decarbonize electricity systems. Due to multiple and interdependent technologies and sectors, as well as opposing objectives such as minimizing cost and reducing emissions, energy system models are used to develop optimal transition pathways towards decarbonized electricity systems. Research in this domain has increased in recent years and multiple studies have used energy system modeling (ESM) to shed light on possible transition pathways for national electricity systems. However, in many cases, the large number of model-based studies makes it difficult for policymakers to navigate study results and condense diverging pathways into a coherent picture. We conduct an in-depth review of ESM publications covering Switzerland, Germany, France, and Italy, and analyze the main trends regarding electricity generation mixes, key supply and storage technology trends, and the role of demand developments. Our findings show that diverging solutions are proposed regarding technology mixes in 2030 and 2050, not all of which meet current climate targets. Additionally, our analysis suggests that natural gas, solar, and wind will continue to be key actors in the electricity system transition, whereas the role of storage remains opaque and calls for clearer policy support. We conclude that due to diverging targets and the current energy landscape in each country considered, different options appear as prominent transition pathways, meaning that individual sets of policies are necessary for each case. Nonetheless, international collaborations will be essential to ensure a swift electricity system transition by 2050.