Policy-driven City Energy Systems Planning -Modelling long-term Strategies

Licentiatavhandling, 2025

To limit global warming to well below 2°C, deep and rapid reductions of greenhouse gas emissions are indispensable. Cities account for around 75% of total global energy consumption and contribute to 70% of total emissions. Cities play critical roles towards achieving decarbonisation targets and contributing to national climate actions. This thesis investigates the impact of city energy plans and associated short-term targets and their alignment with national and regional climate objectives while addressing key sectoral interactions within the energy systems’ development pathways.
An integrated approach is employed, encompassing inter-connected demand-side and supply-side dynamics. The long-term decarbonisation targets and policy measures are incorporated using a cost optimisation model. The TIMES model generator is used to develop the TIMES_Northern European city model, which is characterised by high heating and transportation demands. Gothenburg is chosen as the representative case, to evaluate the impacts of its energy plan and its alignment with Swedish and European climate objectives. With the implementation of policy-based scenarios, long-term sectoral developments of the heating and transportation sectors are evaluated. To facilitate the representation of technological parameters based on demographic characteristics, the city has been spatially divided into five sub-regions.
The implementation of the city energy plan results in a 33% reduction in cumulative carbon dioxide emissions compared to the reference case. The city energy plan leads to deep and rapid emission reductions, although, due to its short-term nature, it results in higher annual emissions in Year 2050 compared to the national and regional objectives. The results for heating supply options emphasise the declining cost-effectiveness of district heating as new apartments shift from district heating to heat pumps over time. New single-family housing chooses heat pumps as their primary heating option. Cost-efficient transport sector developments show a rapid deployment of biofuel-driven vehicles, followed by a gradual increase in electrification to meet emissions reduction targets. For passenger cars, the results indicate eventual 100% penetration of electric vehicles, with timelines that vary according to policy interventions and sub-regional factors. Gradual investments in low-voltage distribution grid infrastructure are essential for enabling the electrification of residential heating and passenger vehicles, with capacity needs surpassing 100% of the existing grid capacity in high-density sub-regions.
This study presents the impacts of local energy plans and their alignment with long-term national and regional climate targets. Aligning short-term plans with long-term decarbonisation targets is crucial to achieving significant and rapid emissions reductions that are sustainable in the long term. The findings also emphasise the importance of integrated energy systems modelling to capture the interplay between supply-side and demand-side dynamics at the city and sub-regional levels, while accounting for sectoral interactions in their development pathways.