The German solar thermal market more than doubled in 2008. According to the solar industry association BSW-Solar and the heating industry association BDH; 2.1 million m2 of new collector area (1.5 GWth) were installed on German roofs last year (940,000 m2 = 658 MWth in 2007). This proves to be a great success after the downswing in 2007, when the German solar thermal market experienced a 40 % decrease in collector area installations.
But where does this market figure come from? BSW-Solar and BDH send a monthly request to their members, asking them for their sales figures. Collector and tank manufacturers then report their sales to a lawyer on a strictly confidential basis. Only the combined sales figures are published. In numbers: 1,530,000 m2 of flat plate collectors and 183,000 m2 of vacuum tube collectors were sold by the industry in 2008, according to the BDH / BSW statistics. Some imports are not included in the survey, and a few manufacturers do not participate. The associations estimates their survey covers 82 % of the entire market. This assessment leads to the great market volume mentioned above.
A crosscheck with data from the governmental support scheme, however, raises some interesting questions. Approved applications for the national rebate programme MAP are fed into a database called “Solaratlas”. The solar thermal users have to hand in their application form for the rebate programme within six months after the installed system has begun operating. This way, the database “Solaratlas” gives a clear overview of how many systems have actually been installed – excluding the last half year, of course. The following table shows that the “in operation figures” of the Solaratlas are much smaller than the amount of shipped square metres of collector area stated by the BDH / BSW statistics.
|BDH / BSW-solar statistics in the first half of 2008 [m2]||Total market volume (statistic plus 18 %) in the first half of 2008 [m2]||Rebated solar thermal installations by Solaratlas, in operation since the first half of 2008 [m2]||Difference between Solaratlas and BDH / BSW statistic [m2]|
|Flat plate collectors||589,757||696,913||469,860||-33%|
|Vacuum tube collectors||70,749||83,483||59,924||-28%|
Different sources of market information showing large differences in their reported figures. Source: BDH / BSW statistics, Solaratlas (eclareon, Berlin, Germany)
The discrepancy could be explained as follows: There is a delay between shipping the components and having the systems up and running. This can cause a certain margin of error if figures for total national market volume are only based on BDH / BSW statistics. The installed collector area in 2008 is most probably not as high as 2.1 million m2 - but even so an impressive market growth.