Costs and potentials of heat savings in existing buildings in Europe

Abstract

With the objective to reach carbon neutrality in 2050, the European Union (EU) institutionalised the Energy Efficiency First principle (EE1st) in its legislation. For decarbonising the EU’s building stock, which accounts for around a third of current EU-wide energy-related CO2 emissions, this principle means that investments in supply infrastructure should only be considered if demand side efficiency measures are not available or more costly. The aim of this thesis is to provide new insights for the application of the EE1st principle at local, national and EU-level by quantifying costs and potentials for heat savings in buildings together with their sensitivity to various influencing factors.The analyses in this work are based on a bottom-up representation of existing building stocks in the form of building archetypes. Costs for achieving different levels of heat savings in the building stocks are quantified by identifying combinations of thermal renovation packages in different building archetypes within two case studies: an analysis at national level for six countries using a ranking approach, and an analysis at local level for three cities using an optimisation approach. The latter analysis also considers a spatially explicit representation of the buildings and the results. In a third case study different thermal renovation packages are combined with carbon-neutral supply options in the buildings. With an optimisation approach those combinations are identified leading to the lowest total system costs for achieving 95% reduction of emissions for heating in buildings of all EU-27 countries until 2050.The work confirms that thermal renovation of existing buildings is a technically as well as economically important measure for increasing energy efficiency of space heating in the EU for achieving carbon neutrality until 2050. Economically viable levels of heat savings in a nearly decarbonised building stock in 2050 could be expected between a quarter and a third of final energy demand for space and water heating in 2019. The economic viability of heat savings shows a notable sensitivity to the current state of the building stock, potential barriers to thermal renovation, to cost assumptions and to capital recovery expectations. At the same time the results suggest that some form of thermal renovation will most likely be economically viable in all buildings built before 2019 until 2050. The costs for achieving different levels of heat savings are also found to be notably sensitive to the characteristics of the stocks like status of renovation and potential barriers, as well as to the exact calculation procedure. In this context, the results underscore the relevance of considering the rebound effect after thermal renovation. Overall, the work highlights the importance of data as well as transparency in assumptions and methods for heat planning at all geographical levels.Further research is suggested to better understand the difference between measured energy consumption and calculated energy demand for space and water heating, how to integrate the status as well as barriers to thermal renovation especially in local level analyses, and to understand the effects of considering wider benefits of thermal renovation on economically viable levels of heat savings in buildings until 2050.