Modeling policies for the EU building stock decarbonization at sub-national resolution

• EU-27 buildings energy demand is projected up to 2050 at sub-national resolution • Energy renovation investments need to increase by roughly 18% • A large share of total costs needs to be covered by the public • When using subsidies, public support should roughly match private investments • Spatial clustering of renovation activities should be expected Understanding how the energy needs of different sectors will evolve in the future is key to informing climate policy design. For the buildings sector, this involves considering heterogeneity in technological, socioeconomic and climatic conditions. This paper develops a building energy sectoral model for Europe that considers technology adoption dynamics at the subnational scale, with high (0.5 ∘ × 0.5 ∘ ) resolution. The model focuses on energy efficiency by considering building renovation, space heating, space cooling, and their interplay. Wide-scale renovation waves in Europe are simulated, understanding where more household renovation efforts should be expected, and where policy support will be most needed in the following decades. Space cooling energy demand increase is expected, along with a substantial reduction of space heating energy demand and a general electrification of end-uses. This study implies that energy renovation investments in EU27 in the 2020-2050 period need to increase by roughly 18%, with respect to historical data, to significantly reduce energy demand and emissions. Spatial clustering of renovation activities, which this work uncovers with unprecedented detail across the EU both between and within countries, should be anticipated and explicitly accounted for in the design of European-level policy instruments. To increase renovation rates through subsidies, public government support should roughly match private investments, especially in those regions where the conditions of the building stock, construction costs and energy expenditures might not motivate households to renovate. This is a significant departure from the last decade during which private investments have been about 20 times higher than public ones, and a targeted use of EU funds and Emission Trading Systems revenues should be considered to address this gap.