Leag and Pfalzwerke wanted to build the entire facility on the dry lake bed and then float it. Unexpectedly heavy rain during the construction phase thwarted these plans.
“Around 4% of the solar boats in the western part of the system have been affected by damage,” said Margarita Schulz, spokeswoman for Lausitz Energie Bergbau AG (Leag). The energy supplier is the operator of the system. On December 20, the company confirmed in response to a request from pv magazine that modules on the edge area of ??the system had been damaged by a storm. Further inquiries initially remained unanswered.
At the beginning of this week, Leag responded to another query by saying that solar modules were underwater and had to be recovered, while pontoons had been washed up on the banks. “There was no damage to the bollards or other system components such as transformers,” Schulz continued. The modules and pontoons came loose in mid-December during a strong wind event. “We do not yet have any definitive information on how high the wind speed and wave height were at the site of the damage,” Schulz said. According to measurements by the German Weather Service (DWD), the peak wind speeds in Cottbus from December 15 to 17 were around 14 m per second. Experts must assess whether these values ??are sufficient to cause such damage to the floating photovoltaic system.
“In the part of the system that was most badly affected, the substructure could not withstand the load of wind and waves,” said Susanne Münch, spokeswoman for Pfalzwerke. The company from Ludwigshafen am Rhein is implementing the construction as an EPC service provider on behalf of LEFPV Cottbuser Ostsee GmbH & Co. KG.
“Due to its exposed location, the west side is increasingly exposed to the effects of the weather. The first minor damages from isolated weather events occurred as early as the second half of 2024,” Münch added. Without protection, floating PV systems are exposed to strong physical influences that place mechanical stress on the structure of the system.
Additional protective measures
Leag is now planning protective measures, including the construction of a breakwater, which is to begin in the spring, said Schulz. To prevent further damage, undamaged parts of the system have been additionally secured, especially on the west, north and south sides. After the damage became known, Leag began to secure the system and salvage damaged parts of the system. However, there is still no concrete plan for repairing or salvaging the sunken solar modules. “A repair concept is currently being developed. A concept is also being developed for the recovery of the damaged solar modules,” Schulz stated. When asked, she did not provide any information on the estimated damage or who will bear the costs.
The floating PV system on the Cottbus Ostsee, where coal was mined until 2015, is the largest of its kind in Germany, according to Leag. It was originally supposed to deliver 29 MW of power from the beginning of the year with almost 51,000 floating solar modules, and thus be able to supply around 8,000 households with electricity every year.
Construction was planned on dry land
Initially, Leag and Pfalzwerke wanted to build the entire system on the dry lake bed and then float it. However, due to unexpectedly heavy rainfall over the last two years, the water level rose faster than predicted, so that construction on dry ground was no longer possible and the concept had to be adapted at short notice, Schulz explained.
The system was not yet in operation when the damage occurred late last year. According to original announcements, it was supposed to go into operation at the 2024-2025 turn of the year. Leag is keeping the date of commissioning open. It depends on a change in Germany's Renewable Energy Act, which is currently awaiting approval under EU state aid law and is not expected to come into effect before July, Schulz added.
