Revamping for a more efficient rooftop system
The revamping project
Legislation in Germany allows operators of ground-mounted solar parks and large rooftop PV systems to replace defective or degraded solar modules with new ones—without losing the original EEG remuneration for the remaining payment period.
Seizing this opportunity, the operator Technische Werke Schussental GmbH & Co. KG (tws) and the operations manager JUWI GmbH carried out a revamping project on a rooftop solar installation in Böblingen, after cracks were discovered in the backsheet of several solar modules.
As part of the revamping project in Böblingen, all old modules were dismantled and replaced with new, more efficient solar modules.
Defects detected, revamping recommended
JUWI is responsible for the technical operations management of the twelve-year-old rooftop solar installation in Böblingen. During routine inspections, JUWI’s O&M service experts discovered cracks in the backsheet of several solar modules. The system was commissioned in 2013, and modules from that production year are known to have quality issues.
Cracked backsheets can pose a fire hazard. Thanks to JUWI’s many years of expertise, the defects were quickly identified and solutions proposed. This led to the decision to carry out a revamping.
Following an in-depth evaluation, 64 percent of the 5,500 installed modules were claimed under warranty. The operator, tws, received replacement modules from the manufacturer—delivering greater performance —as compensation.
The revamping process
Before the start of the revamping project, the entire solar installation was dismantled, as a complete roof renovation of the logistics hall was carried out as part of the overall project. Once the date for the roof renovation was set, JUWI had only nine weeks to prepare in order to start the project on time.
Due to the age of the system and the dismantling process, the components were no longer suitable for reinstallation. Therefore, not only the solar modules but also other components—such as the main DC cables, cable trays, substructure, and generator junction boxes—were replaced to ensure the long-term quality and efficiency of the solar installation.
The project benefited from JUWI’s extensive revamping expertise: over the past eight years, the company has replaced around 725,500 modules across 17 solar parks, amounting to a total capacity of approximately 120 megawatts. This expertise was applied to the revamping project in Böblingen to ensure its successful execution despite the short preparation time.
A particular highlight is JUWI’s long-standing experience in module replacement, which contributed to the professional and efficient execution of the project. Thanks to our long and productive collaboration, we are happy to entrust our projects to JUWI’s operations management team.
Expansion of PV capacity planned on decommissioned site area
JUWI installed only as many new modules as needed to restore the original rated capacity, ensuring that the existing EEG remuneration remains valid. This also means that 15 percent of the roof area remains unused.
The operator plans to install an additional PV system with approximately 400 kWp on the newly available space to directly supply electricity to the logistics company in the building via a Power Purchase Agreement (PPA). Any surplus electricity could also be marketed through the power exchange.