Photovoltaic plants in Saxony: Development, status and perspectives

Purpose
The development and the perspectives of photovoltaic plants (PVP) in Saxony will be described. The development reflects the effects of the different funding instruments as well as the technical progress which has been made during the past 15 years.

Funding as accelerator
The first large step in the PVP installation in Saxony was done with the German 1000-Roofs-Program between 1991 and 1995. In the frame of this program the first 150 PVP were installed with a total power of 450 kW (see Fig.1). A new high light was set when the 100.000-Roofs-Program came into force. More than 450 PVP with a total power of 1,5 MW were connected to the grid. With the EEG (Renewable Energy Act) this development was continued. Starting with 2004 also Megawatt PVP were put into operation, the PVP Espenhain (5 MW power) belongs also today to the world largest PVP.

Technical development
The first PVPs reflect the technical level of the early nineties. The power was limited to 5 kW, and the DC-voltage was restricted to 140 V. Beginning with the year 2000 the mean power of the PVP has been clearly increased. Sonny Boy is the dominating inverter type (with a share of more than 50 %), but the module types vary strongly. An increase in the mean module power has been certainly observed.

Some operation results
A mean annual yield of 750 kWh/kW was found for the first generation of PVP, which was influenced by the low quality of some module types. New systematic monitoring programs were started in 2000. These investigations allowed the evaluation of new built PVP (yields up to 1000 kWh/KW, Fig. 2), but also the long time behaviour of the older PVP could be observed (Figs. 3 and 4).

Conclusions
The development generally confirms the politically decisions for PV funding in Germany. It could be proofed, that new PVPs in Saxony with optimal design and components, respectively, can generate up to 950 kWh/kW in an "average" year.