Planning for climate neutrality in the Nordic power sector: Insights from a non-harmonised comparison of eight energy system models

Abstract

The Nordic countries have adopted ambitious climate targets that require far-reaching power-sector transformations, making energy system modelling an important input to long-term planning. However, model-based evidence is produced using different model structures, assumptions, scopes, and scenario designs. This paper examines what can be learned from comparing such independently developed scenarios by assessing Nordic power-sector climate-neutrality pathways across eight structurally diverse energy system models. The comparison covers Denmark, Finland, Norway, and Sweden for 2030, 2040, and 2050, and focuses on electricity demand, generation capacity, CCS deployment, and power-sector CO2 emissions. Inputs are not harmonised; instead, outputs are compared using a common reporting basis reflecting how modelling evidence is encountered in applied policy contexts. The results show broad agreement on the direction of transition. Wind power, mainly onshore but complemented by offshore wind in some countries, is the clearest cross-model finding and forms the backbone of the Nordic power system by 2050. At the same time, installed capacities, CCS deployment, nuclear outcomes, and emissions levels vary substantially. These differences are interpreted considering renewable-resource potentials, technology availability, policy constraints, sectoral and geographical scope, emissions-accounting boundaries, and different implementations of climate-neutrality targets. The study shows that non-harmonised model comparisons can support policy analysis by identifying where models point in the same direction, such as wind expansion, and where outcomes depend more strongly on model and scenario assumptions, such as CCS, nuclear, and net-negative emissions. For policy use, the findings underline the need to report model scope, technology representation, policy constraints, and emissions-accounting boundaries..