Policy Instruments: The Case of Germany - Nearly Zero Energy Building Refurbishment - page 18

Fig. 2 CO 2 emissions from the German building stock dependent on different renovation rates,
years 1990-2020 (Bettgenhäuser et al. 2012 )
It becomes obvious, how important the energy-related refurbishment of the
building stock is. Figure 2 shows that the emission target of the government will
just be reached, if it is possible to at least increase the major energy-related
refurbishment rate to a value of about 1.8 % per annum. But even if the topic of
energy-related building refurbishments is generally acknowledged as an important
issue, currently there still is no source of information which frequently measures
the renovation rate in the building stock. However, there are several sources of
information, which present very diverse numbers. According to Friedrich et al.
( 2008 ), the refurbishment rate was 2.2 % in 2006; according to KfW ( 2009 ), it was
2 % in 2009; according to BMWi ( 2010b ), it was 1 % in 2010; according to
Discher ( 2010 ), it was 0.9-1.3 %; and according to Diefenbach et al. ( 2010 ), for
existing buildings constructed before 1979, it was 1.28 % in the period
2000-2004, 0.95 % in the period 2005-2008 and 1.12 % in 2009. As can be seen,
the presented numbers are all in a range between 0.9 and 2.2 %, and as different
approaches and definitions have been used by the respective authors, it cannot
clearly been determined which rate is the most reliable. Nevertheless, Friedrich
et al. ( 2008 ) and Diefenbach et al. ( 2010 ) conducted quite comprehensive surveys
in their research projects, and thus, these values have a better scientific basis than
the values of the other sources although they present the minimum and the
maximum value. The main difference is the definition of 'refurbishment'. Friedrich
et al. ( 2008 ) defined it as complete energy-related refurbishments and Diefenbach
et al. ( 2010 ) just focused on measures that improve the building shell of buildings.
However, when considering all presented estimations, it becomes more realistic
that the current major renovation rate is still far below the necessary 1.8 %.