Supporting climate-neutral cities with urban energy modeling: a review of building retrofit scenarios, focused on decision-making, energy and environmental performance, and cost

Climate deadlines are fast approaching, and city action plans must address slashing carbon emissions using scarce financial resources. Urban energy modeling (UEM) supports building sector transformation by quantifying energy use and emissions in baseline and retrofit scenarios. Additionally, many UEM studies evaluate retrofit costs and financial returns. This review of 26 UEM studies critically analyzes how studies decide to model retrofit measures or impose scenario constraints, and how energy, emissions, and costs are quantified. The results show divergent quantification approaches among the reviewed literature, hindering the usefulness and comparability of the studies for policymakers. The findings also indicate challenges with renewable energy production and heating via heat pumps, including increased peak electrical loads and seasonal mismatches in generation and consumption, which are mitigated by measures reducing building energy demand and energy use, demand-response measures to curtail peaks, and district sources of endogenous energy. The value of the decision-making analysis is to signal pathways toward innovation and stakeholder collaboration for city plans, highlighting approaches using context analysis to generate and share energy in districts, economic criteria to mirror real-world conditions, and stakeholder engagement to meet local priorities. Finally, perspectives for future UEM studies support policymakers guiding the transformation to climate neutrality.