Germany-headquartered RWE completed a 5 MW PV system on the roof of SIGNAL IDUNA PARK as part of its partnership with Borussia Dortmund. The installation used 11132 modules and was confirmed by the German Record Institute as the world’s most powerful PV system on a stadium roof. The system enabled BVB to cover up to half of the stadium’s electricity demand and was expected to reduce 1700 tons of CO₂ per year. A 3.7 MWh battery storage unit was under construction for early 2026 to supply power when solar output was unavailable. RWE and BVB had earlier installed 200 modules on the Fan World building in April 2024 and entered a six-year partnership in summer 2024. Executives from both organisations has noted the project’s significance for operational planning and long-term energy goals.