Space heating accounts for around 25% of the final energy consumption in the European Union. As we strive for climate neutrality by 2050, in line with the European Green Deal, effective energy system modeling is essential for developing robust strategies. However, integrating energy efficiency into the building sector presents challenges due to the lack of comprehensive methodologies and data regarding specific energy use, heated areas, and costs related to retrofitting.

A new scientific article by Eurac Research - published on the Journal of Building Engineering in collaboration with e-think Energy Research and Technische Universität Wien - proposes a methodology for deriving country-specific cost curves for energy savings in building space heating across the EU-27. This methodology leverages clustering analysis and open data from the Hotmaps project to assist energy system modelers in incorporating energy efficiency measures into decarbonization strategies aligned with the European Green Deal.

Eurac Research applied a dynamic building simulation model using open data from Hotmaps and Eurostat, utilizing clustering analysis to categorize building stocks across the EU-27. They calculated detailed energy savings cost curves for various retrofit measures, such as insulation of facades and roofs, and provided insights into the cost-effectiveness of these measures in different climatic and insulation conditions.

"The novelty of this paper lies in several key innovations. First, it proposes a framework to derive heat-saving cost curves for building stock retrofitting using openly available online data sources, which are accessible at no cost. This approach primarily utilizes harmonized data from the Hotmaps project, which provides building stock characteristics and retrofit costs for all EU-27 Member States at the country level, supplemented by other open data sources such as Eurostat for validation"says Ulrich Filippi Oberegger, first author of the study.

"A second novelty is the application of this methodology to calculate cost curves for each EU-27 Member State, whereas previous studies have typically focused on only a subset of these countries. The third novelty lies in the adoption of a high temporal resolution approach for building simulations, using dynamic models with hourly timesteps. This advancement enables more accurate modeling of energy dynamics within buildings by capturing variations in weather, equipment schedules, and occupancy patterns, which lower-resolution models often overlook"continues the author.

The comprehensive categorization of building stocks and retrofit measures, coupled with detailed charts and reporting, enhances the granularity and interpretability of the energy savings cost curves. This detailed approach provides a more precise tool for assessing the cost-effectiveness of energy efficiency interventions and contributes to more effective energy-saving strategies in building management and policymaking.

"These detailed energy savings cost curves are essential for developing realistic decarbonization pathways through energy system modeling. With these curves, we can better evaluate the trade-offs between building retrofits and other energy system investments such as installation of renewables of storage, leading to more cost-effective strategies for achieving climate neutrality" says Matteo Giacomo Prina, second author of the study.

This research offers valuable insights for policymakers and stakeholders committed to achieving climate-neutral targets, guiding them in making informed decisions that promote energy efficiency in the building sector.

Link to the original scientific article