Inter-comparison of spatial models for high shares of renewable electricity in Switzerland

This study presents an inter-comparison of three structurally different electricity system models (EXPANSE, Nexus-e, and OREES) with sub-national spatial resolution in Switzerland in 2035. We analyze technology and regional implications of three targets for electricity generation from new renewable sources (17 to 25 TWh/year from solar PV, wind, biomass, and waste incineration) and compare results at a national level as well as at a higher spatial resolution of Swiss cantons and municipalities. All three models align on high capacities of solar PV in 2035 as the key technology for reaching the three targets, but there is flexibility where PV can be placed to achieve the targets: either on roofs and facades or also on land. Electricity interconnection with Europe remains of key importance in Switzerland because any increases in electricity demand or lower deployment of new renewable generation are compensated by import. For the rest, the three models provide internally-consistent storylines of future strategies for Switzerland: a future with a diversified range of technologies (EXPANSE), a future with the focus on decentralized rooftop solar PV with batteries (Nexus-e), and a future with the prioritization of most productive areas for wind and solar PV, including open-field PV (OREES).