Rooftop turbines feed the building-integrated wind debate

Four newly installed wind turbines in downtown Portland, Ore., are spurring nationwide discussion on the benefits of rooftop wind.

Source: Colin Miner, New York Times; BuildingGreen

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Four wind turbines, rising 45 ft above a 22-story building in downtown Portland, Ore., won't produce a significant amount of power - but that's fine with the architects who put them there, according to New York Times blogger Colin Miner.

"This is more about generating knowledge than electricity," said John Breshears of Zimmer Gunsul Frasca Architects , which developed the project atop Twelve West , a new, mixed-use tower in Portland's West End. "The more we learn the better we're going to be at this."

The turbines will produce just 9,000 kW yearly, or 1% of the building's electricity needs, according to Oregon Live . However, Breshears and his partner Craig Briscoe suggest that the turbines will provide much-needed data on the efficacy of urban rooftop wind farming, which has generated a good deal of interest across the nation . "People think that in an urban setting you won't be able to harness the wind in an effective fashion," Briscoe said. "We think we're going to be able to show otherwise."

However, not all agree that it's money well spent. According to Oregon Live, critics say the investment would be better used improving building energy efficiencies or erecting turbine towers on windblown rural sites and dedicating their energy to the new building.

Building Green released an in-depth report in May about the follies of building-integrated wind. The prohibitive size and weight needed to generate cost-effective power and vibration generated by spinning blades that can ripple through a building's frame are just some of the problems that would befall rooftop turbines. Rooftops often lack enough laminar wind to turn the turbines effectively, which make the turbines much unlikely to generate their rated output.

The Portland architects, however, remain undeterred, pointing out they have designed an efficient building that they expect will receive two U.S. Green Building Council LEED platinum certifications for new construction and commercial interiors.

"More than half the world's population live in cities now," said Briscoe. "We need to get a lot better about how we provide for those people." The question remains whether building-integrated wind can accomplish this.