San Francisco PUC to Put City Wind to Use

DAVIS, Calif. — The winds that famously chill the streets of downtown San Francisco will help power a skyscraper set to open in the fall that could pave the way for a new world market for energy-generating wind turbines in new buildings.

The new headquarters for the San Francisco Public Utilities Commission (PUC) will use a design developed with the help of engineering professors from the University of California, Davis. The design incorporates an external vertical "wing" of wind turbines that stretch up to the roof and will produce at least 7 percent of the building’s energy needs, according to a statement from the university.

The project developed with the help of Bruce White, professor of mechanical and aerospace engineering and former dean of the university’s College of Engineering, and Case Van Dam, professor and chair of the Department of Mechanical and Aerospace Engineering, who serve as co-leaders of the UC Davis Wind Energy Collaborative. The collaborative is one of six campus centers on renewable energy administered by the UC Davis Energy Institute, which administers research, education and outreach programs and partners with other institutes and centers in related areas.

White has worked with his team on several consulting and advising projects in San Francisco and said he knows the city’s winds better than those in his own backyard.

His project list includes a wind analysis for the site of AT&T Park, home of the San Francisco Giants, which university officials say may well have helped Barry Bonds to earn some of his home runs.

When the university’s Wind Energy Collaborative was first contacted about the new building, White and his colleagues had already conducted ground-level studies of winds in downtown San Francisco that determined it would be economically feasible to install wind energy devices on high-rise buildings in the city — including 525 Golden Gate Ave., the site of the utility commission’s headquarters.

"Tenth and Market is known to be one of the windiest areas in San Francisco," White said. "It’s anecdotally famous for high winds and kiosks rolling down Market Street, and for people being blown over.”

Three nearby high-rises — Fox Plaza, the Bank of American Data Center and the California State Automobile Association — funnel the wind through and re-direct it down to the 10th and Market intersection, White explained.

“When the wind is coming in the right direction, it’s really something," he said.

Though the Utility Commission had previously obtained a wind analysis from Ontario, Canada-based consulting firm RWDI, Masoud Vafaei, engineer with the commission and a graduate of UC Davis, persuaded the PUC to seek a second opinion.

"At the time of that earlier analysis, the San Francisco PUC hadn’t nailed down the building’s shape or additional features, so they also contacted Case for advice on what sort of wind energy device to use,” White said.

Graduate students at the university built a model to test in the College of Engineering’s wind tunnel.

"San Francisco, in terms of being an environmentally conscious city, always has been a leader," White says. "This project will reinforce that image. The commission wanted to demonstrate that this is feasible; they want to show the way."

But while 10th and Market is a particularly attractive location for a wind-power project, high ground-level winds are not essential, according to the university.

"In terms of applications for wind energy and renewables, every city is a potential candidate," White said. "As you go up, the wind increases. Once you’re 200 feet or above, you get strong winds everywhere on Earth.”

While urban settings typically don’t offer high-quality standards for wind farms, they allow cutting out the middleman — the power generated can be used in the building rather than going through a power utility.

“You can be one-third as efficient as a wind farm, and still be economically feasible," White said.

Wind energy facilities do present controversy in the incidence and dangers of bird strikes but the city has taken it into account with the orientation of the building, which should minimize the problem, White said.

"The vertical axis design does not affect avian life because it’s like part of a building, and birds don’t fly into buildings," White said. "Horizontal-axis turbines potentially would have generated better wind energy, but, politically, the vertical ones are more acceptable from both the safety viewpoint and the avian viewpoint. There should be very few bird kills, if any at all."

White said he is optimistic that wind turbines can be integrated into new buildings in an aesthetically pleasing way, improving energy efficiency, and realizing great commercial potential.

"While it’s true that San Francisco’s pedestrian-level ground winds are higher than in most cities — Chicago also has this feature — all cities have the ability to use wind energy devices on high-rises,” he said. “A tremendous world market could be developed."