Emissions and power demand in optimal energy retrofit scenarios of the Finnish building stock by 2050

Highlights • Optimized energy retrofits reduced energy consumption of building archetypes. • Four retrofitting scenarios for Finnish building stock by 2050 were analyzed. • District heating demand was reduced by 25–63 % compared to business-as-usual by 2050. • Electricity demand did not rise despite increased heat pump deployment. • CO2 emissions in the retrofit scenarios were reduced by 50–75 % by 2050.Finland and the European Union aim to reduce CO2 emissions by 80–100 % before 2050. This requires drastic changes in all emissions-generating sectors. In the building sector, all new buildings are required to be nearly zero energy buildings. However, 79 % of buildings in Finland were built before 2000, meaning that they lack heat recovery and suffer from badly insulated facades. This study presents four large-scale building energy retrofit scenarios, showing the emission reduction potential in the whole Finnish building stock. Six basic building types with several age categories and heating systems were used to model the energy demand in the building stock. Retrofitted building configurations were chosen using simulation-based multi-objective optimisation and combined according to a novel building stock model. After large-scale building retrofits, the national district heating demand was reduced by 25–63 % compared to the business as usual development scenario. Despite a large increase in the number of heat pumps in the system, retrofits in buildings with direct electric heating can prevent the rise of national electricity consumption. CO2 emissions in the different scenarios were reduced by 50–75 % by 2050 using current emissions factors