Tracked megawatt PV plants: Operation results 2008 in Germany and Spain

An increasing number of 2-axis tracked Megawatt PV plants have been put into operation during the last years. The higher final yield of such plants (compared to plants with fixed generator orientation) must be paid with higher plant costs and larger area consumption. The absolute yield is determined by the insolation conditions at the sites. The paper compares design and operation results of four 2-axis tracked plants operating in Germany and Spain in 2008, which are representative PV sites in Europe.

The plant locations are distributed between 37 and 50 degrees northern latitude (Fig.1), in South Spain and Central Germany. Some technical features of the investigated plants are given in the table below.

plant total power /MW tracker Plant area/m² module supplier
Borna 3.44 Solon 210000 Solon
Penig 0,2 Deger 22000 Sanyo,Sharp,SunLink
Alqueria 1.02 Solon 125000 Solon
Ventanas 1.01 Solon 102000 Solon

The used tracker systems differ in their construction and in the applied tracking principle. Whereas the Solon mover (Fig. 2) follows every 10 minutes the astronomic sun path, the Deger tracker (Fig. 3) tries to find the optimal generator position also at cloudy conditions. The tracker distance varies between the both used tracker types and the sites. The most plants started their operation in 2007. The operation of the plants was monitored by the owners or by professional service providers.

The operation results of the year 2008 are exemplarily presented. The solar irradiance in 2008 in Germany was higher than the long year average, similar to the years before. The final yield of the both plants is about 1300 kWh/kW (Fig. 4), with an advantage of 8 % for the plant using Deger trackers. The annual performance ratio was fond to be 82 %.
The yields of the Spain plants exceed the yield of the German plants with 2250 kWh/kW by more than 70 %. Only in one month (May) the yield of the German reaches the yield of the Spain plants due to the extraordinary insolation in Germany (high) and Spain (low), respectively. The performance ratios of the Spain plants were also about 82 %.
A number of operation details will be given.
Finally a long term estimation of the yield for the different plants will be given.