Werner Hiller, Technische Universitat Chemnitz, D-09107 Chemnitz

Udo Rindelhardt, Forschungszentrum Rossendorf e. V., PF 510119, D-01314 Dresden

Ingo Voigtlander, Solaris-VerwaltungsGmbH, 09116 Chemnitz

Even in former East Germany, photovoltaic was being used increasingly for generating electricity. Through weaker buying power the absolute numbers are far lower than in the western federal states, but a series of remarkable results was achieved nonetheless. This paper discusses the developments in the federal state Saxony.

It is based on long term results on selected photo-voltaic plants as well as data recorded by the regional electricity supplier Energieversorgung Ostsachsen (ESAG), Dresden, in 2002 and 2003 [1].

Development of installed power and the systems engineering

In 1990, the first (and only) photo-voltaic power system (PVS) of the GDR (East Germany) was connected with the ESAG network (East Saxony) in Oberseifersdorf. From 1992 to 1994, in the frame of the German 1000-roofs-program 150 PVS with a total power of 523 kW followed. According to the conditions of this program these PVS had an power between 1 and 5 kW. This program was intended to test various technologies, as well as to attempt to standardize the PVS design. Modules from about 10 European manufacturers came to be used; thereby inverters with various designs and manufacturers were utilized. As at that time the predominant tendency was to run the PV-generator in the extra-low voltage range (i. e. <110V), several PVS, in particular the larger ones, showed many parallel strings (up to 20 and more).

In 1994 the first larger plant was built at the Kirnitzschtalbahn near Bad Schandau. This PVS had an output of 40 kW and is still the largest PVS in the ESAG net. Between 1995 and 1999, growth stagnated in PVS. Remarkable growth occurred only with the implementation of the EEG as well as the 100,000-roofs-program did in the year 2000. Figure 1 shows the development in the net of the regional supplier ESAG until the end of 2003. In the frame of the 100,000-roofs-program totally 405 pVs with a power of 1,5 MW were put into operation in Saxony. The average PV power plant capacity has not changed in recent years, when compared with the older PVS; it lies around 3-4 kW. Even the number of larger PV power plants, which were mostly built by investors, has remained small. The power of 100 kW has only two times exceeded, so far.

For the newer PVS, the transition to the (one-)string-concept is technically characteristic. Through the higher admissible generator voltages and the use of string-inverters, the cabling is much simplified. The market leader SMA with its model SunnyBoy also clearly dominates in Saxony among inverters. Conversely, since the year 2000 a noticeable number of new modules has appeared on the market, even from smaller manufacturers. Modules of the Dresden firm Solarwatt alone are represented in many PVS; only Siemens (now Shell), Kyocera and ASE (now Schott Solar) are worth mentioning alongside. Other PVS are divided among 20 other manufacturers. A detailed analysis of the results of each module would not be meaningful, since even recently similar modules use different solar cells, depending on the manufacturer [2]. Altogether, about 1000 photovoltaic power plants were being used in Saxony at the end of 2003, with a total capacity of about 4 MW.

year

Figure 1: Development of grid connected PVS in the ESAG net