Form and Function in Harmony - Wacker Chemie AG

Form and Function in Harmony

Weser Stadium: a Trendsetter in Solar-Generated Electricity

Seen from the air, the perimeter of the reconstructed stadium will keep its oval form. Also remaining are the floodlight masts, landmark features recognizable from afar due to their distinctive pairs of slender concrete pillars. The new facade will envelop the existing modern office towers at the north end, the grandstands and the roof, and give the stadium a monolithic appearance.

After reconstruction, the stands will be positioned in a rectangle around the “hallowed turf”; seating behind the goals at the curved east and west ends will be straightened up, and all the stands brought right up to the pitch. The roof will be somewhat higher than before, almost floating over the stadium bowl. Add to that an infrastructure of the highest standards and an innovative energy plan.

Solar energy will be generated from the southern and eastern sections of the facade, as well as from the entire roof of the revamped arena. The total area is nearly equal to that of two soccer fields. The approximately 200,000 solar cells that make up this installation have a combined output of over 1 megawatt, and will feed around 750,000 kilowatt hours into the grid annually. In so doing, they will save the emission of more than 400 metric tons of carbon dioxide per year. In the world of sports, this photovoltaic array is a record breaker: no other sporting arena in Germany can come close – Weser Stadium is number one.

Plastic Panels: Lightweight and Flexible in Design

After the planned three phases of construction are complete, the circa 250 to 300 kilowatt nominal output of the roof’s inner ring will deliver nearly a quarter of the installation’s total energy capacity. The solar panels installed in the inner ring do not just produce electricity; they act as conventional roof glazing and, as such, can be seen by every visitor. The architects responsible for this renovation intend these panels to serve as an innovative design element. “This project clearly demonstrates Werder Bremen’s commitment to solar energy,” says Professor Andreas Wöll, general manager of SUNOVATION GmbH in Elsenfeld (near Frankfurt a.M.). Here, in the extreme northwestern corner of Bavaria, his company produces the attractively designed panels that make up the inner roof ring.

Prof. Andreas Wöll, general manager of Sunovation GmbH, holds a panel for the inner ring of the stadium roof.

It was soon obvious to the planners and architects that conventional glass/glass panels, i.e. solar panels sandwiched between glass plates, would not work because of their weight. The new roof is supported on the existing concrete substructure, which has a limited load-bearing capacity. But it also projects much farther into the stadium bowl than the old one did, and for that reason, imposes a substantial static load. Thus, the panels for the roof’s inner ring need to weigh as little as possible. “The agency commissioned to remodel the stadium chose our SUNOVATION® panels, in which the solar cells are permanently embedded between two high-grade, transparent and permanently flexible plastic sheets,” explains Professor Wöll. “With these custom-made panels, we can fulfill not only the static requirements but also the desire for a pleasing aesthetic.” The plastic used by the manufacturer to produce the panels, Makrolon® (polycarbonate) or Plexiglas® (polymethyl methacrylate, or PMMA), depends upon the service conditions of the panels. Recently, pro K (the German Industrial Association of Semi-Finished and Consumer Plastic Products) designated the SUNOVATION® solar panel as its 2009 product of the year.