LAUSR

Abstract The need to accelerate energy retrofitting and integrate renewable energies in the built environment sector has been recognized by the European Union and its member states, with many policies and directives already in place. However, compared with single building retrofitting, there are no established approaches for energy retrofitting at district and urban scales, in part due to the complexity of the computational problem and the decision-making process. In the transition towards low-carbon cities, new approaches to assess a variety of energy efficiency and renewable energy generation solutions for large building stocks at acceptable computational costs are needed. Moreover, stakeholders require flexible and adaptable tools to support the selection of the most cost-effective retrofitting scenario. In this context, this study proposes a new methodology for the planning of energy retrofitting at urban scale. By extending the system boundary from single buildings to a whole district, local energy potentials and innovative measures can be identified. Furthermore, an integrative approach involving a large variety of energy conservation and renewable energy generation measures, evaluated at different scales and levels of detail is proposed. Finally, a simple but flexible tool to aid the decision-making process has been developed. The tool chooses the best performing measures out of a variety of alternatives, prioritizes them in order of their cost-efficiency, and generates a retrofitting roadmap for the district depending on the desired goal or capital of the project. The results can be adapted to changing parameters such as energy prices or CO2-emissions, ensuring the flexibility and adaptability of the decision-making process throughout the implementation.