Materealistic? How European energy system models exceed raw material reserves

Decarbonising energy systems reduces emissions and fossil fuel dependency, but expanding renewables increases demands for critical raw materials. Most energy system models, however, neglect material demands, putting the material feasibility of energy scenarios at question. We combine a systematic review of 59 highly decarbonised European energy system modelling studies with a quantitative ex-post assessment of material demands for 5 key technologies and 19 materials. We find that material demands exceed Europe's population-based shares of current global reserves for seven materials (Ga, In, Ir, Te; less pronounced for Ag, Se, V), in particular if multiple sectors of the energy system are considered. Competing non-energy demand further amplifies the scarcity, while technological innovation can either alleviate or intensify it. We conclude that energy efficiency, recycling, expanding reserves and technological innovation may only partly address the identified shortages and call for energy sufficiency measures to achieve sustainability in the energy-material nexus.