Supporting municipal energy transition through modelling of possible future energy scenarios: A case study of Kungälv, Sweden

Abstract

Municipalities and municipal utility companies have been found to be excellent drivers for the energy transition that is required to meet climate goals [1, 2]. However, municipal energy planning procedures and tools frequently do not account for the interactions between electric distribution grids and district heating networks [2, 3]. Storage solutions for either heat or electrical energy have been similarly disregarded. In this thesis, a methodology for design and evaluation of transition scenarios for a mid-sized municipality is proposed and applied in a case study of the Swedish municipality of Kungälv. Historical data on load profiles in both electrical and district heating grids is analyzed and used for creation of compound load profiles, which serve as the basis for a robust approach to generating synthetic load curves in alternative development scenarios. A time-discrete numerical calculation model for simulation of cost-optimal system operation on a seasonal scale is introduced. The effects of a range of growth scenarios for local renewable electricity generation and the district heating system on the system behaviour and associated costs are investigated. Heat storage systems are proposed and their effect on the system is analysed. The results suggest that utility-scale battery storage and seasonal heat storage could be beneficial to the system by lowering energy prices. Synergies between storage and increased local intermittent electricity production are shown. Seasonal heat storage is especially beneficial in scenarios with high usage of district heating, where significant peak generation capacities can be replaced.