Impact of operational details and temporal representations on investment planning in energy systems dominated by wind and solar

Planning of future energy systems with higher prevalence of wind and solar energy requires a careful representation of the temporal and operational characteristics of the system in the investment planning model. This study aims to identify the aspects that should be considered when selecting the representation for a particular system. To demonstrate the impacts that various model representations have in terms of model accuracy and computational effort, we carry out case studies on two test systems implemented within the Backbone energy systems modelling framework. The results show that the temporal and operational representations have different benefits and weaknesses in different system types. The findings provide general guidelines on the relative importance of different model details, depending on the characteristics of the system under study. For example, some temporal sampling strategies can better capture long-term storage needs, while others are more suitable for short-term storage modelling. Likewise, solar-dominated and wind-dominated systems differ in their methodological requirements. Furthermore, the interactions between energy sectors and the operational limits of the technologies for sector coupling should be correctly captured, as they significantly impact on the value of different technologies and their flexibility. Finally, we recommend testing several temporal and technical representations for each particular system in order to ensure the feasibility of the selected method for that purpose. The findings and recommendations inform energy system modellers about improvements that will facilitate higher quality planning results.