Abstract
Energy system models are increasingly used to support planning and decision-making in the energy
transition, but growing system complexity challenges their ability to provide robust and policy-relevant
insights. This report, developed within Research Area 1 of FME InterPlay, identifies key research gaps in
modelling of integrated energy systems and outlines strategic directions to strengthen model-based
decision support.
Based on a survey of Norwegian modelling teams and a review of the scientific literature, the report
highlights three main challenges. First, many models provide limited representation of end-use demand
dynamics, constraining their ability to capture interactions between supply, demand, technology choices,
and fuel switching. Second, while model coupling is widely used to increase detail and scope, insufficient
alignment of assumptions and internal logic often leads to fragmented or inconsistent results. Third,
non-energy perspectives, such as biodiversity, are weakly integrated, reducing the relevance of model
results for real-world decisions that extend beyond least-cost solutions.
In addition, modelling teams report persistent biases related to grid constraints and flexibility needs. Further
structural uncertainty, uncertainty from the model design and analytical approach, is rarely addressed
systematically. Rather than uniformly increasing model complexity, the report emphasises the importance
of identifying which model details are essential for answering specific research and policy questions.
Together, the findings define clear research priorities for FME InterPlay: strengthening demand
representation, improving transparency and alignment in model coupling, integrating non-energy
perspectives more directly, and enhancing model robustness under real-world operating conditions.