Simulation versus Optimisation: Theoretical Positions in Energy System Modelling

TLDR

In recent years, several tools and models have been developed for designing and analyzing future national energy systems, focusing on integrating renewable resources and transforming fossil‑based systems, but their diversity often yields differing results and recommendations. This paper analyses the diversity of these models and their implicit or explicit theoretical backgrounds. The authors define and compare two archetypes: prescriptive investment optimisation (optimal solutions) and analytical simulation or alternatives assessment approaches. Recognizing the differing theoretical assumptions clarifies model differences, explains result dissimilarities, and provides a foundation for interpreting outcomes of the two archetypes. Keywords: energy system analysis, investment optimisation models, simulations models, modelling theory, renewable energy.

Abstract

In recent years, several tools and models have been developed and used for the design and analysis of future national energy systems. Many of these models focus on the integration of various renewable energy resources and the transformation of existing fossil-based energy systems into future sustainable energy systems. The models are diverse and often end up with different results and recommendations. This paper analyses this diversity of models and their implicit or explicit theoretical backgrounds. In particular, two archetypes are defined and compared. On the one hand, the prescriptive investment optimisation or optimal solutions approach. On the other hand the analytical simulation or alternatives assessment approach. Awareness of the dissimilar theoretical assumption behind the models clarifies differences between the models, explains dissimilarities in results, and provides a theoretical and methodological foundation for understanding and interpreting results from the two archetypes. Keywords: energy system analysis; investment optimisation models; simulations models; modelling theory;renewable energy