Open Access

Lotte Nawothnig, Toshiyuki Kudo, Manfred Rauschen, Stefan Thomas, Naoko Doi, Kunstmann Sascha, Toshiya Okamura, Fiona Bunge, Martin Pöter, Melanie Bierhoff, Thomas Rühle, Jonas Rütter

• Established in 2016, the German-Japanese Energy Transition Council (GJETC) strives to promote bilateral cooperation between Germany and Japan on energy transition. Among other studies and topical papers, an output paper in 2020 (Rauschen et al., 2020) already compared the energy efficiency in buildings in both countries with a particular focus on heating and cooling. One important finding of this output paper was that further efforts in the building sector are needed to improve the energy efficiency of buildings in Germany and Japan. Following the more ambitious climate protection targets in both countries, this study seeks to analyze the German and Japanese policies put in place to accelerate the decarbonization of the building sector. TheEstablished in 2016, the German-Japanese Energy Transition Council (GJETC) strives to promote bilateral cooperation between Germany and Japan on energy transition. Among other studies and topical papers, an output paper in 2020 (Rauschen et al., 2020) already compared the energy efficiency in buildings in both countries with a particular focus on heating and cooling. One important finding of this output paper was that further efforts in the building sector are needed to improve the energy efficiency of buildings in Germany and Japan. Following the more ambitious climate protection targets in both countries, this study seeks to analyze the German and Japanese policies put in place to accelerate the decarbonization of the building sector. The decarbonization of the vast number of buildings that both Japan and Germany are facing will be a major contribution to achieving the GHG reduction targets of both countries and should continue to be discussed among experts and developed into a discussion among policy makers. This report examines and compares the characteristics of the building stock in both countries, as well as existing policies and new strategies and policies that are planned or discussed to achieve energy conservation and decarbonization of buildings. The current shape of buildings, especially houses, is greatly influenced by the land area of the country corresponding to the available space for buildings, the natural environment surrounding the country, the natural resources available, and the lifestyle and cultural ideas that have been passed down and taken root over time. Therefore, it might be difficult to compare them and the corresponding strategies and policies with the same yardstick, so we also discuss common or deviant situations. Through this joint research, we aim to find each other's advantages and challenges and to develop useful and concrete policy recommendations that will contribute to decarbonization policies in both countries.…