This report aims to answer the following question: Which are the most cost-effective ways to decarbonise the existing EU building sector through energy renovations? Replying this, we provide a method and a dataset to investigate the cost-optimal level of energy efficiency measures in combination with low carbon heating and cooling solutions. To showcase the application of the method, two EU Member States (Germany and Greece) are examined and targeted renovation solutions are discussed as examples.
This work begins with the characterisation of the current state of the very diverse EU building stock. Information is collected from European projects and the EU building observatory. This information is analysed and restructured to provide a harmonised and ready-to-use dataset. This dataset is presented for the two exemplary cases, Germany and Greece.
Next, the method developed to assess the combination of insulation measures and efficient heating and cooling supply technologies for the existing residential EU building stock is presented. The method uses the basic principles of Cost Benefit Analysis (CBA) from an economic perspective. It allows the evaluation of the energy performance of different energy renovation options and their global costs. Through its application, we identify the cost effective and cost optimal solutions and how much primary energy and greenhouse gas emission reductions they achieve.
The study is performed on the existing EU building stock and explores the effect of both the current and future energy system fuel mixes. We consider the 2020 and 2030 fuel energy system mixes to better understand the impact of the power sector to the heating and cooling sector in the built environment.
By testing this method in Germany and Greece, we reach valuable results that contribute to a better understanding on how optimal energy building renovation strategies differ in southern and central Europe — when both heating and cooling are considered. The cost-optimal solution requires moderate thermal insulation in southern Europe, while efficient heating and cooling technologies should be prioritised. In other words, deep building envelope renovations are not always cost-optimal, nor do they necessarily maximise the environmental benefits. On the other hand, in central Europe deep energy efficiency improvements are cost-optimal and should be combined with efficient heating and cooling technologies.
Based on the outcomes from the two countries we tested, it is concluded that a holistic approach incorporating both energy efficiency and sustainable heating and cooling should be considered when planning the decarbonisation of the building sector. In other words, the transformation of both the energy system and the built environment in particular, has to be designed in coordination to avoid lock-in effects in terms of investments, or over investments in less than cost-optimal energy efficiency renovations, and the shortening of the renovation cycles of buildings. Ultimately, our work aims to set the fact-basis to reply to challenging policy questions on how to transform the built environment in the EU.JRC.C.7-Knowledge for the Energy Unio
