City energy transitions: Modelling policy alignments with sectoral integration at sub-city levels

Cities have implemented strategies to transform their energy systems and support national and regional climate action. However, studies examining their long-term alignment remain limited. This study aims to investigate how local energy strategies align with national and regional climate objectives. Scenarios aligned with local, national, and European policy are formulated. Cost-optimization model, based on TIMES, is developed to analyse long-term developments in the heating and transportation sectors. Spatial characterization of demographics is utilized to analyse sectoral developments at sub-city levels. Distribution grid infrastructure and bioresource allocation are accounted for. With applied policy scenarios, significant reduction in emissions is observed compared to the reference scenario. Due to varying intermediary targets, large gaps exist in the emission trajectories across scenarios in the near-term. The city energy plan yields a 33 % reduction in cumulative emissions, while national plans achieve a 25 % reduction relative to the reference case. At the sectoral level, residential heating and cars shift towards electrification, and penetration rates differ with applied policy and socio-economic conditions. In areas with little to no existing electrified heating, distribution grid capacity needs to more than double to support the accelerated electrification. The use of bio-resources exhibits a gradual increase in the heating sector, while peaking around 2030 in the transportation sector before declining to nearly zero by 2050. The changing utilization of bio-resources highlights their varying role in the transition of the different sectors. The study shows considerable short-term policy misalignment with potential impacts on cost-optimal developments. Electrification and bioresources play key roles in the decarbonization journey. • Integrated city energy systems model analyzing city and national climate objectives • Findings show near term policy misalignment at different governance levels. • Sub-city characterization of demographics impacts model outcomes. • Distribution grid infrastructure is crucial to long-term systems planning. • Bioresources have varying roles in heating and transport sector decarbonization.