Solar photovoltaic (PV) energy is a crucial supply technology in the envisioned renewable energy system. With enormous amounts of PV modules being installed, some will be affected by early-life failures and the resulting e-waste from PV modules is raising environmental concerns. A failure of growing importance is the defect in the glass layer(s) of glass-glass PV modules. In this research, an experimental glass repair technique for glass-glass PV m. Solar photovoltaic (PV) energy is a crucial supply technology in the envisioned renewable energy system. With enormous amounts of PV modules being installed, some will be affected by early-life failures and the resulting e-waste from PV modules is raising environmental concerns. A failure of growing importance is the defect in the glass layer(s) of glass-glass PV modules. In this research, an experimental glass repair technique for glass-glass PV modules was tested and examined. The PV modules with glass defects under test did not show internal defects in the PV cells, while the repaired specimens performed properly at each phase in the repair process compared to reference modules, the IEC standards and manufacturer warranty. After a damp-heat test the repaired PV modules showed no signs of water ingress, suggesting that the glass layer was restored as a proper barrier. However, definite conclusions should be made with caution since the non-repaired specimens neither showed visible signs of water ingress. While the practical application of the reparation technique has still some uncertainties, glass reparation is found to be technically feasible and effective. Furthermore, economic and energetic analyses indicate that glass defect reparation is economically interesting and energetically desirable.••••Testing of experimental glass repair technique for glass-glass PV modules.••After damp-heat test repaired modules showed no signs of water ingress.••Economic and ecological feasibility shown using Cost Priority Number metric.Glass-glass PV repairPV refurbishmentExperimental repair techniqueGlass defect reparationThe photovoltaics (PV) energy industry is currently evolving from a niche market into one of the world's most important energy supply technologies. The combination of cost decrease and improved efficiency will accelerate solar PV deployment to surpass the installed capacity of natural gas and coal by 2024, becoming the world's number one installed energy source for electricity. Renewable energy sources have little related lifetime GHG emissions compared to the current fossil energy system. However, worldwide PV deployment requires enormous amounts of minerals, including scarce minerals such as silver, zinc and indium. As a result, global PV deployment could place these mineral supply chains under tension, leading to higher prices for PV energy which may delay the transition to a fossil-free energy system.A valuable option to limit the reliance on the mineral supply chain, is the recovery of minerals in decommissioned PV modules [4,5]. Decommissioned PV modules contain the minerals required to produce new PV modules. However, not all valuable materials can be recovered. The most energy-intensive parts, photovoltaic cells, cannot be recovered yet. Therefore, the PV sector is developing new measures to decrease the material requirement, following the reduce-, repair- and recovery-pathway [7,8]. The reparation of defect PV modules is a valuable option in this pathway. Repair techniques ca. 2.1. Double-glass PV modulesIn double-glass or glass-glass PV modules the polymer back sheet layer is replaced by a glass layer identical to the top glass, creating a symmetrical “sandwich” structure. The PV cells are in the center, compressed by an encapsulant film and glass layers. The establishment of a glass back layer has several advantages compared to regular GBS modules with respect to an increased reliability, enhanced performance, and improved mechanical strength. Firstly, a significant advantage of glass-glass PV modules is the option for bifacial PV cells. This type of PV cell converts (indirect) light at the rear side of the module into electricity. However, glass-glass PV modules are not bifacial by definition. The application of bifacial PV cells comes at a certain cost, which may not be economically attractive in every application scenario.Secondly, an important advantage that does apply to all glass-glass PV modules, is the reduced water vapor transmittance (WVT) ratio. Water vapor ingress typically occurs at the more permeable polymer back layer of regular GBS PV modules, and the WVT ratio quantifies the water-permeability of materials. Encapsulated moisture in the internal parts of PV modules affects the reliability and may cause various issues, e.g., corrosion, delamination and connection failure. The replacement of the back sheet layer with a glass panel drastically reduce.
