Second-life PV modules turned into solar balconies in Germany

Aphotovoltaic reuse initiative in Kassel, Germany, has repurposed 300 used solar modules to create 150 balcony PV systems.

The panels, which had operated for 13 years on the roof of an industrial building, were inspected, refurbished and distributed to participants in an upcycling project organized by ClimateHub Kassel and solar collective SoLocal Energy.

The project began with inspections of the 300 recovered modules. Twelve panels showed minor defects and were discarded, while the remaining modules were cleaned and fitted with new connectors for use in balcony PV systems. The recovered modules represent around 6 metric tons of material that would otherwise have entered recycling streams, where only certain material fractions can be recovered.

The organizers introduced a tiered pricing model to make the systems accessible to households with different budgets. Complete packages include modules, an inverter, mounting equipment, cabling and accessories, as well as electrical connection, system registration and monitoring setup.

A system comprising two 325 W CSW Excellent modules, for a total capacity of 650 W, costs €825 ($937) under the subsidized tariff, €1,000 at the standard rate and €1,175 under the solidarity tariff. A single-module system costs €650, €775 and €900, respectively. A four-module configuration using CSW Diamond panels has a combined capacity of 1.78 kW and costs €2,025 under the highest pricing tier specified by the organizers.

Participants can also collect the equipment and install the systems themselves. Two-module systems are supplied with a Hoymiles HMS-800W-2T microinverter. Three- and four-module systems use either two SUN-M80 units or one Hoymiles HMS-1600-4WB inverter, with dynamic power control limiting total output to 800 W.

An optional storage package, comprising a Zendure SolarFlow 800 Pro 2 battery and an energy meter, costs an additional €600 to €700, depending on the pricing tier. Professional-grade modules are also available for €30 more per panel than the Diamond modules.

Several local organizations provided logistical and technical support. Bauteilbörse handled 13 pallets of modules, while BürgerSolarBeratung and energy cooperative Bürgerenergiegenossenschaft Kassel & Söhre provided technical assistance. Cargo bikes were made available to help participants transport the modules.

German nonprofit organization Deutsche Gesellschaft für Sonnenenergie (DGS) also made a donation to reduce the cost of inverters and mounting equipment for some low-income households.