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Toyo Ito's Biggest Building: A Stadium That's Secretly a Solar Power Plant

2013 Pritzker Prize winner Toyo Ito began his career with luminous and transparent houses in his native Japan. But a sports stadium put him on the map.

Toyo Ito's ascendancy into the architectural Pantheon—solidified by his winning of the Pritzker Prize today—began with the luminous and transparent houses and public buildings he designed in his native Japan. But it was his largest and most unlikely commission, designing a stadium for Kaohsiung, Taiwan's second largest city, that would land him on the map of architectural kings.

Known for its surf-side location and abundant sun, tropical Kaohsiung served as host of the July 2009 World Games, a once-every-four-years event featuring sports not included in the Olympics, like tug of warnetballorienteering, and Latin dance. It was a radical departure for Ito (he'd never designed anything like a stadium before) and the design was radical too. Dramatically light for such a heavy building, it looked as unusual as the sports it hosted, rugby sevens and flying disc. But its secret weapon was its solar-powered skin, which made it the world's first stadium to draw most of its energy from the sun.


"Since solar panels were required for this project, I thought to use them to cover almost the entire stadium seating roof," Ito told me in an interview in 2009. While photovoltaic panels are often tacked onto buildings—including other stadiums, most notably the Stade de Suisse in Bern—the ones used in Kaohsiung are anything but an add-on. The heavy reliance on steel at stadiums (think of the Bird's Nest in Beijing) often give these buildings an environmental footprint that green technology can't easily offset. In Taiwan, a new logic is at play. Ito went all out, covering the entirety of the 22,000 sq. meter roof in waves of 8,844 photovoltaic panels, embedded in frames of laminated glass. Ito also set the stadium on a 15-degree angle along the north-south axis to protect spectators from sun and maximize natural ventilation.

The stadium's lightness extends to its aesthetics. On a formal level, Ito was addressing a question that has animated his work on other public buildings, like concert halls and libraries: how to bind the inside and outside. "The interior space of stadiums is generally closed and isolated from its surroundings," he told me in 2009, when I wrote about the building for Domus. So he designed the roof -- a spectacular web of 32 spiraling steel pipes set atop a primary skeleton of concrete ribs -- so that it unfurls on one of the stadium's short sides, with two extensions that curl outwards.


The resulting structure suggests an open-ended, natural eroticism, as appropriate for sports as it is for the Internet era. “I sometimes feel that we are losing an intuitive sense of our own bodies," Ito has said before. "Children don’t run around outside as much as they did. They sit in front of computer games. Some architects have been trying to find a language for this new generation, with very minimalist spaces. I am looking for something more primitive, a kind of abstraction that still has a sense of the body.”

Top: Stadium; bottom: Ito's Sendai Mediatheque in Tokyo

The building's "C" shape suggests a luxuriating dragon, and opens the stadium up to visitors and the surrounding 16 acre park in a glorious, natural gesture. This shifts the focus away from the stadium's central race track and toward the flow of visitors moving from a nearby subway stop to the stadium, blurring the lines that separate athletes from spectators. Employing parametric computer modeling, Ito's engineers also arranged the seats to ensure maximum intimacy with the field, a considerable feat given the stadium's 40,000 seats.

"Most stadiums have a clear center," he said. "I attempted to create a dynamic space which opens outward. I also wanted to bring the seats and the field closer together. Since the site is a public park for citizens to use freely, I have given special consideration to creating a sense of unity within the park."


The airiness of the arena recalls Frei Otto's famous tent-ringed Olympic stadium in Munich, as well as Herzog and de Meuron and Ai Weiwei's Beijing "Bird's Nest." Next to that stadium, whose heavy branches of interlacing steel conflate facade and structure—and signify openness and restriction—Ito's building looks like a featherweight. (It happens that one antecedent of the Kaohsiung stadium's helical roof is the cross-stitched bulbous plastic facade of Herzog and de Meuron's previous stadium, the Allianz Arena, which is also in Munich.)

Fitting the 8,844 solar panels along the roof's curving spiral to create a smooth, snake-like skin was the project's greatest challenge, Ito said. The panels are capable of providing the stadium with 80% of its electricity during game time, and of eliminating some 660 tons of carbon dioxide a year. The building's self-sustainability is also considerable insurance against the dreaded "white elephant" label that Olympic stadiums tend to earn after their first use: when it is not hosting an event, the stadium becomes a de facto power generator, capable of powering the building's 3,300 lights and two jumbo screens. When it's not being used, officials have estimated, the stadium can sell enough electricity to the local power utility to earn the city government over $150,000 per year.

Technology may be an integral part of Ito's work, but it isn't a crutch. Beyond solar, the stadium's greatest asset is its open and seductive design, one of the finest elaborations of an ethereal architectural approach Ito articulated in 1991: "My tastes run to wafting, dreamlike architecture. Less form than ‘field,’ architecture with a center yet no clear boundaries."


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