The Sonnenwagen Aachen team completed the 2026 iLumen European Solar Challenge at Circuit Zolder in Belgium with two vehicles. The current Sonnenwagen, the Æthon, finished in fifth place after 24 hours of racing, while its predecessor, the Adelie, finished in sixth. Together, the two solar cars completed 528 laps. In qualifying, the Adelie secured pole position with the fastest lap, while the Æthon started from fifth place. A total of 26 solar cars from 22 teams representing 15 countries competed.
The track at Zolder demanded a great deal from the teams. Tight corners, elevation changes, and fluctuating weather conditions made it necessary to continuously balance speed and energy consumption. Rain during the night and on Sunday morning posed additional challenges, leading to several incidents among the field. Around 6 a.m., Adelie’s rear end spun out; the vehicle tipped over and had to be brought back to the pit. No one was injured. After repairs, the solar car returned to the track and, despite the time lost, still finished in sixth place.
Partnership in Development and Racing
“This race demanded everything from us,” says Nassim Lagrou, team leader of Team Sonnenwagen Aachen. “After the incident with Adelie, it was clear to us that we weren’t going to give up. The team repaired the vehicle and got it back on the track.” Fifth and sixth place are a strong result, and at the same time, the team is taking away important insights for further development.
Covestro has supported the Aachen-based team since its founding in 2017 and has been its main sponsor and technology partner since 2018. In the spring of 2026, the collaboration was extended for another two years. In addition to financial support, the partnership focuses primarily on technical exchange: The team contributes requirements and experience from development, testing, and racing, while Covestro contributes material and application expertise. Monique Buch, Chief Commercial Officer at Covestro, says: “This achievement demonstrates what a partnership can accomplish: The team contributes its deep understanding of the vehicle and its ideas, while Covestro contributes its expertise in materials and applications.”
Materials Used in the Sonnenwagen
The current Æthon solar car uses more than ten different materials from Covestro. These include, among others, raw materials for a chemically recycled foam in the driver’s seat, mass-balanced Vulkollan for damping between the battery and the body, and the thermally conductive polycarbonate Makrolon TC for the battery cell holders. “Mass-balanced” means that the proportion of bio-based and/or recycled raw materials is mathematically allocated to the product.
With the race in Zolder behind them, the team is already looking ahead to the next vehicle. The insights gained from the European Solar Challenge are being incorporated into the development of a new solar car, with which the team plans to compete in the 2027 Bridgestone World Solar Challenge in Australia. The goal is to build on the top finish achieved in 2025 and improve upon it even further.