Preparations of the bottom of the Eastern Lake for Germany’s largest floating PV system have begun

Vibro-compaction processes are used for ground modification

The preparatory work for the construction of a floating PV system of up to 18 hectares on the future 1,900 hectare Cottbus Eastern Lake has begun. The German energy company LEAG is currently compensating the tilted subsoil in the former Cottbus-Nord opencast mine by means of vibro-compaction. The energy company is thus going upfront in order to be able to carry out the first work for the plant, which is still to be approved by the City of Cottbus, “in the dry”. LEAG and the project developer EP New Energies (EPNE) plan to make an innovative contribution to the expansion of renewable energies in Lusatia and thus to the energy transition. The 21 MW plant would be the largest floating PV project realized in Germany up to now.

“Unlike systems that are installed on water surfaces, we first had to develop a technical solution for the installation of our floating PV system that enables floating without the system changing its position. Together with partners, we have developed a system based on dolphins that enables the desired floating on site in the future Eastern Lake“ says the head of Geotechnics at LEAG, Franziska Uhlig-May. The plant will be built around pipes rammed into the subsoil, so-called dolphins with a diameter of about 30 to 40 centimeters. Before the dolphins can be driven into the subsoil, the tilted subsoil must be extensively grouted at depths of up to 30 meters.

“For the compensation of the tilted bottom, the proven method of vibro-compaction is again used, with which we have already compacted the shores of the two nature conservation islands and the tilted shore areas in the future Cottbus Eastern Lake. Our subsidiary GMB is at our side with its technology and know-how,“ explains Uhlig-May. GMB uses the LR 1300 crawler crane with an operating weight of around 290 tonnes and a 35-metre-long lance with a vibrator for vibro-compaction. Especially in the area of the future 34 anchor points as locations for the dolphins, a vibrating grid compacted to two meters is planned.

In addition to the anchor points, compaction measures are also carried out for a safety support body, which is intended to protect the planned installation from moving into low positions, as well as for an access path that will be used during the installation of the installation. In total, this project results in around 40,000 running meters that are processed by means of vibro-compaction. In recent weeks, the vibro-compactor has been delivered with several low-loader transports from its previous location in Greifenhain and equipped for its use at an assembly site on the edge of the Cottbus Eastern Lake.  At the end of March 2022, the work on vibro-compaction is to be completed.
The planning and control of the entire project of the floating solar system is carried out by the EPNE with the support of the LEAG departments. It coordinates the entire value chain from technical design, approval planning and construction of the photovoltaic system to the operational handover to LEAG.

“Floating PV systems are currently still a niche in Germany. We want to change that with this system. Artificial standing waters, such as opencast lignite mining lakes, are low-conflict from an aquatic ecology and socio-economic perspective and offer a lot of potential for the expansion of floating PV. This technology is becoming another pillar of the energy transition,” said Dr. Ralf Schwarz, head of project development at EPNE. “The floating PV potential, which is located quite significantly here in Lusatia, can be developed with the technology of LEAG and GMB.”

Your contact for further information:

Kathi GerstnerLEAG, Press Officer,

+49 (0) 355 2887 3010, kathi.gerstner@leag.de

 

Margarita SchulzEPNE, HR & Communications Manager

+49 (0) 30 767584572, margarita.schulz@epne.de