Why Borussia Dortmund's Solar Stadium Roof is World's Best

In Germany, Borussia Dortmund's Westfalenstadion has become home to the world's most powerful photovoltaic system ever installed on a stadium roof, offering a potential template for other venues grappling with rising energy costs and mounting pressure to reduce carbon emissions.

The installation at Signal Iduna Park, Germany's largest stadium, comprises 11,132 solar modules and is expected to deliver more than 5 MW at its peak, surpassing the previous record held by the 4.2 MW array at Istanbul's Nef Stadium.

The system was developed through a six-year sustainability partnership between the Bundesliga club and German energy company RWE, which signed on as BVB's premium sustainability partner in the summer of 2024.

The venue's expansive roof offered a substantial surface area which proved perfect for accommodating such an ambitious renewable energy installation.

Practical impact on stadium operations

Beyond the record-breaking specifications, the practical benefits of Dortmund's new energy system could be substantial.

The installation should enable the club to cover around half of the stadium's total electricity requirements through solar power alone, potentially cutting its bills and carbon footprint.

According to BVB's own project data, the system will save around 1,700 tonnes of CO₂ annually compared to the stadium's previous power supply arrangements.

A 3.7 MWh battery storage facility is also under construction and is expected to be operational by early 2026.

This addition will allow the club to draw on solar-generated electricity even when the Ruhr Valley has grey skies.

Leadership's perspectives on sustainability

Hans-Joachim Watzke, the club's CEO, sees the project as just one puzzle piece in Dortmund's long-term sustainability jigsaw.

"Signal Iduna Park symbolises our integrated efforts to ensure Borussia Dortmund's future viability," he says.

"We are delighted that our home can now be associated with a record-breaking flagship project for climate protection."

BVB Managing Director Carsten Cramer says: "Together with RWE, we have achieved a real milestone in our sustainability partnership – with targeted regional impact and global appeal.

"This project is a key component of our decarbonisation strategy and is the ideal contribution to our commitment and our goal of working with our partners to continuously improve and take on more responsibility."

Regulatory momentum in sports

The Dortmund installation arrives as the Bundesliga tightens its sustainability expectations across the league.

The German Football League became the first major professional football league to anchor environmental requirements in its licensing regulations from the 2023-24 season.

Clubs must now demonstrate strategies analysing their emissions and set reduction targets as a condition of league participation.

Markus Krebber, CEO of RWE, says: "We are proud to have set a new record with BVB, one of Germany's most internationally renowned football clubs.

"Together, we have installed the world's most powerful solar system on the roof of Germany's largest stadium.

"This is a powerful statement in favour of efficient climate protection and is the result of the work of two teams that are perfectly aligned in their commitment to sustainability."