Diverse efforts in the same direction: A multi-model comparison of climate-neutrality power sector pathways for the Nordic countries

arXiv:2603.26719v2 Announce Type: replace Abstract: The Nordic countries have adopted ambitious climate targets that imply far-reaching transformations of their power sectors, making energy system modelling a central input to long-term policy analysis. At the same time, comparing results across studies remains challenging due to differences in model structure, assumptions, and data. This paper presents a comparative assessment of Nordic power sector transition pathways across four Nordic countries, based on eight structurally diverse energy system models analysed without harmonising inputs in order to reflect prevailing modelling practice. The comparison covers the years 2030, 2040, and 2050, and focuses on where model outcomes converge or diverge across key indicators including generation capacity, CCS deployment, and power-sector CO2eq emissions. Across models, there is broad agreement on a transition dominated by variable renewable energy, with wind power forming the backbone of the power system by 2050, complemented by solar photovoltaics. At the same time, projected capacity levels, CCS deployment, and emissions outcomes vary substantially. These differences are linked to variations in renewable resource assumptions, technology scope, system boundaries, and other structural modelling choices. Net-zero outcomes range from small residual emissions to net-negative values, reflecting differences in how models define and operationalise climate targets. The results highlight both the value and the limitations of non-harmonised multi-model comparisons. While they provide a useful picture of the range of outcomes that can emerge in practice, they also underline the need for transparent assumptions and cautious interpretation when using model results in planning and policy contexts.