TH Köln is researching sustainable solar modules

September 4, 2026

Source: E & M powernews

As part of the “GreenSolarModules” project, the Cologne University of Applied Sciences (TH Köln) investigated materials and repair concepts for solar modules while also analyzing their carbon footprint.

Together with research and industry partners,TH Köln has developed new materials and design approaches intended to make solar modules more recyclable and repairable. As part of the collaborative “GreenSolarModules” project, the researchers investigated, among other things, thinner solar glass, alternative plastic films, and removable encapsulants for junction boxes, according to a recent press release from the institute.

Solar modules consist of, among other things, glass, plastic films, solar cells, electronics, and an aluminum frame. Because the way these components are joined has so far made it difficult to separate the materials—and thus hindered recycling and repairs—the research project focused on individual components and materials, according to the press release.

“To address these challenges, we have developed solutions for more energy-efficient and environmentally friendly materials, as well as a new, repairable junction box design,” explains Ulf Blieske of the Cologne Institute for Renewable Energy (CIRE) at the Technical University of Cologne. He led the subproject on sustainable module design and repairability.

Thinner Solar Glass Put to the Test

With regard to solar glass, the university investigated a thinner variant, the production of which, according to TH Köln, requires less energy. According to the research team, it became apparent that existing testing procedures from the relevant standards cannot be readily applied to particularly thin glass.

In addition, the researchers investigated the use of the semi-metal antimony, which is used in glass production. According to the project’s findings, solar glass can achieve the required light transmittance even without this additive.

Another area of focus was plastic films designed to protect solar cells from environmental influences and mechanical damage. Variants made from natural raw materials such as wood fibers and rice waste were tested. According to the TH Köln, some of the materials examined proved to be stable and recyclable.

For junction boxes, the team tested removable encapsulants to insulate the electronics installed there. This should make it possible, for example, to replace defective connectors without having to replace the entire junction box or module.

Production in Germany with Lower Emissions

In addition to the technical work, TH Köln compared the environmental footprint and economic aspects of different module variants. The study examined two types of modules produced in Germany and China, as well as the recovery of materials at the end of their useful life.

According to the university, production in Germany results in approximately a quarter fewer greenhouse gas emissions than the manufacturing process in China that was examined. The project also examined regulatory and economic prerequisites for bringing more sustainable modules to market.

The project is now set to continue: According to the TH Köln, part of the consortium has applied for a follow-up project on the recycling of solar glass. The university cites the industrial testing of the developed solutions as a further possible step.

The Fraunhofer Institute for Solar Energy Systems ISE coordinated GreenSolarModules. In addition to TH Köln, other Fraunhofer Institutes and companies from the glass, materials, and recycling industries were involved. According to TH Köln, the Federal Ministry for Economic Affairs and Energy (BMWE) provided approximately 4.37 million euros in funding for the project over three years. The university’s subproject accounted for about 390,000 euros.

Author: Katia Meyer-Tien