Impact of Temporal Resolution of Input Parameters on the Investment Decisions in a Sector-Coupled District Energy System Model

Decentralized energy systems and local renewable energy generation are playing an increasingly important role in ensuring an efficient, sustainable, and resilient energy supply at the distribution grid and district levels. Sector-coupled energy systems, in which heat pumps connect the electricity and heating sectors, require integrated modeling approaches for planning, design, and operation. The choice of temporal resolution of input data represents a methodological trade-off between model accuracy and computational effort. This study provides a systematic analysis of how the temporal resolution of the coefficient of performance (COP) of heat pumps influences optimization results in a sector-coupled microgrid model. In an investment- and dispatch-based optimization model, only the temporal resolution of the COP time series is systematically varied, while all other input data are kept constant. The experimental setup comprises five scenarios, all of which are structured on a 15 min scale. Only the COP time series is aggregated using the arithmetic mean, while still retaining the 15 min scale. This setup allows for a specific focus on the effects of temporal variation on a single parameter, albeit without enabling an assessment of the computational effort involved, since the temporal scale remains equal across all scenarios. For the investigated case study, the results indicate that an hourly COP resolution leads to only minor deviations in both the optimal system design and the dispatch results: The deviations of the key indicators for the hourly COP aggregation scenario relative to the 15 min baseline remain predominantly below 0.1%. With daily aggregation, initial systematic deviations occur in the dimensioning of system components, while coarser aggregation levels lead to pronounced structural distortions of greater than 30% in the capacities of some components. These findings provide methodological orientation for selecting an appropriate COP temporal resolution in microgrid modeling and explain which structural impacts can be expected from the temporal aggregation of COP.