Is a 100% renewable European power system feasible by 2050?

•Seven scenarios for a 100% renewable European power system are modelled for 2050.•A 100% renewable system could operate with the same level of adequacy as today.•Mass mobilisation of Europe’s solid biomass and biogas resources would be required.•90% more generation and 240% more transmission capacity would be needed than today.•Costs would be ∼530 €billion per year, 30% more than a system with nuclear or CCS.