Comparing Methods for Soft-Coupling Energy System Models

Energy system modelling has become a critical analysis tool for decision-makers in the energy transition. These models increase tremendously in complexity as many technologies and large sectoral, temporal, and spatial scopes are often considered. Efforts are therefore made to couple models with different scopes to perform holistic analyses, but coupling methodologies are rarely analysed, validated or even documented. This paper describes three overall categories of previous attempts to create holistic energy system analyses using bi-directional, soft-linked frameworks. Furthermore, a prototype modelling framework is developed for a small Danish-German electricity and hydrogen system with the state-of-the-art open-source energy system models Balmorel and Antares. A validation framework, where Balmorel is coupled with a high temporal resolution version of itself, is also constructed and compared with a comparable Balmorel-Antares run. This framework is utilised to test methods based on market value and loss of load expectation (LOLE). Results from the method comparison indicate that the LOLE approach is more adequate for assessing security of supply. The framework is considered adequate for security of supply assessments, but further work can increase both sectoral and spatial scope to utilise the European potential of both models and include the heating sector as modelled in Balmorel.