The 20 MWp photovoltaic park Ammerland is located in northern Germany about 50 km northwest of Bremen. Due to a technical failure of the PV modules, it was necessary to completely replace the modules in order to rescue the project. The module exchange began after difficult negotiations with various stakeholders at the end of 2016.
Over the course of the park's operational livetime a remarkably strong and steadily increasing degradation of the modules became apparent. The situation became particularly difficult because the PV module manufacturer went bankrupt in mid-2012. Initial negotiations with the insolvency administrator did not lead to the desired result. In 2014, a technical analysis of the modules came to the conclusion that an irreversible design error was responsible for the severe degradation. Thus, a complete exchange of the modules was necessary.
The subsequent negotiations presented an enormous challenge, since a large number of stakeholders were involved.
- Banks were involved, as a complete change could only be achieved through debt refinancing.
- Negotiations with the network operator had to be conducted, as securing the old feed-in tariff was initially only possible if the faultiness of all the modules to be replaced could be proven.
- Intensive negotiations were also conducted with BaFin, as they wanted to classify the PV park as "new" AIFM due to the module change. Which would resulted in more complex reporting obligation.
- Additionelly there was a legal dispute with the insolvency administrator of the module manufacturer.
Ultimately, all points were successfully clarified and thus the module changes were carried out in 2016/2017, without this having any significant impact on profitability.
- The banks provided the capital.
- The old feed-in tariff could be maintained.
- The fund did not have to be reclassified.
- The court ruled in favor of Aquila Capital.
In the photo you can see the PV-Park during the exchange of the modules at the beginning of 2017. The bright modules on the left (polycrystalline) are the new modules, the dark blue modules on the right (thin layer, poorly polished silicon) are the defective modules that are being replaced.
Amorphous silicon (thin-film solar cells): A crystal structure can not be recognized here. During production, a thin silicon layer is vapor-deposited onto a carrier material (glass, plastic). Efficiency: laboratory 11.5%; Production 5 - 8%
Polycrystalline solar cells: Polycrystalline silicon solar cells have an irregular surface on which the crystals with a diameter of a few millimeters to centimeters are clearly visible. They are usually lighter than monocrystalline cells. They are made of silicon that has been heated and poured into mold. Efficiency: laboratory 17.8%; Production 12 - 14%
Monocrystalline: Monocrystalline silicon solar cells can be recognized by their regular, smooth surface, broken corners and the dark blue to black surface. They consist of cultured silicon crystals. Efficiency: laboratory 23.3%; Production 15 - 17.5%