Power play

LOOKING to the ocean as a source of non-polluting electricity, San Francisco city leaders are eager to test a set of wave-powered turbines off Ocean Beach -- if they can raise money, calm surfers and answer questions about environmental effects and smaller swells.

The project, which could begin in May, features a 420-foot-long snake-like device that would float four miles off the beach, collecting wave motion in the same way inland windmills grab gusts.

The project would put San Francisco on the front lines of experimentation with ocean power. Other ocean-energy projects operate in Scotland, Ireland, Norway, Sweden, Portugal, Hawaii and the East Coast.

But the plan faces several obstacles. The estimated cost for the first phase is $6 million, says Peter O’Donnell, senior energy specialist for San Francisco. The city contributed $30,000, and Oakland provided $10,000. San Francisco officials say they are negotiating with private companies to pay the rest. The first step: a 22-month phase of gathering input, seeking permits and filing reports.

Though officials at the Palo Alto-based Electric Power Research Institute said the initial test would have little effect on swells, project development manager Roger Bedard says a full-fledged generating station off Ocean Beach -- one of San Francisco’s most popular surf breaks -- could reduce wave size in some spots by 10% to 20%. (A 10% reduction would shave seven inches from a six-foot wave.)

“There might have to be a meeting halfway between the surfing community and the energy community,” Bedard says.

Surfrider Foundation spokesman Matt McClain wants assurances the machinery at sea won’t harm whales and other marine mammals.

“We just want to make sure that the way we go about this is not endangering either wildlife or human recreation,” McClain says. “We’d like to see some science.”

Waves in the project area usually run 3 to 5 feet tall, occasionally reaching 20 feet. Bedard says the device would not rise more than five feet above the surface.

“You can’t see this from shore. The only time you’d ever see it is from over the Pacific, flying,” or from a boat, says Jared Blumenfeld, director of San Francisco’s environment department.

City officials said the Ocean Beach project’s generation potential of 750 kilowatts would probably run at about 40% capacity, generating enough power to sustain 150 to 200 homes. But, Blumenfeld said, “you really need to have it in the water for a year to tell” its potential.

Meanwhile, San Francisco officials approved another ocean-power project. In that venture, London-based HydroVenturi would pay for and place collection devices 60 feet underwater to capture energy from tidal motion under the Golden Gate. That $4-million effort, twice delayed, could begin as soon as fall, but there too, finances have been uncertain.

“We really want to find technologies that replace dirty power with cleaner power,” Blumenfeld says. “We need to take some calculated risks with new technologies.”