Harnessing sea power: the energy wave of the future?

By Michelle Locke Associated Press Writer
Monday June 11, 2001

Racing across the blue Pacific like wild, white-maned horses, the curling breakers crashing down on California’s beaches are an iconic image of the Golden State. 

Berkeley grad Misha Cornes goes to the beach and sees something more: an energy source tailor-made for power-strapped California. 

Cornes and his colleagues at the Berkeley based start-up Sea Power & Associates think they’ve figured out how to harness the energy in waves. 

Their Wave Rider technology is a series of lightweight concrete floats that would sit one to two miles off shore. Floats are connected to a hydraulic pump that extends about 60 feet down to the ocean floor. The up-and-down motion of the waves creates pressure that drives the hydraulic pump, which then drives turbines to generate electric power. 

The design “seemed to be well thought out and I didn’t see any reason why it wouldn’t work,” says David Navarro of the California Energy Commission. “There’s a lot out there. it’s just waiting to happen.” 

The notion of wiring the waves has been around for a few decades. The problem up to now is that few of the ideas have been tested — although some companies outside the United States have produced power from the ocean — and the cost has been considered prohibitively high compared to other renewable forms of energy such as wind and sun. 

“It’s estimated two-tenths of a percent of the energy contained in the ocean could power the whole world. It’s this energy source that’s totally untapped,” says Cornes. 

While Japan and Northern Europe have forged ahead with government-funded sea power schemes, research dollars in the United States dried up after an initial surge in the 1970s. 

In California, there were talks about trying a few ideas along the coast, but “when the deregulation came through there was no money for research. They all stopped. They all went away,” said Michael Champ, president of the Falls Church, Va.-based Advanced Technology Research Project and an early advocate of ocean power. 

Now, with California battling an energy crisis and a revival of interest in finding sources of energy that don’t come from decomposed dinosaurs, sea power advocates are hoping to see their field get a push. 

“Where we are is where wind was five years ago,” says Mirko Previsic, CEO and founder of Seapower & Associates, who has tested his ideas in wave tanks but needs to raise $3.4 million to build an oceangoing prototype. 

The total power of waves breaking on the world’s coastline could produce two to three million megawatts, Navarro said. In good locations, wave energy density can produce an average 65 megawatts per mile of coastline. One megawatt can power about 750 homes. 

“When you see a wave go by you think of it as the water moving. Well, it’s not the water, it’s the energy within the water that’s making it move,” says Navarro. 

The ocean can produce two types of energy, thermal energy from the sun’s heat and mechanical energy from tides and waves. 

There are three basic ways of converting the kinetic energy that drives a wave into power: 

— Tapered channel systems push the waves into reservoirs and then make the water flow through a turbine, similar to a hydroelectric dam. 

— Float systems use the rise and fall of the waves to drive hydraulic pumps. 

— Oscillating water column systems are fixed generating devices in which waves enter the column and force air up past a turbine. As the wave retreats, the air pressure drops, causing the turbine to turn. 

Last November, the world’s first commercial wave power station, which uses the oscillating water column system, began supplying power to the grid on the small Scottish island of Islay. It’s operated by Wavegen, a pioneer in ocean energy. 

Wave energy has the advantage over wind and sun in that it is constant. There are some concerns about getting permits to place the devices and they would also need to be marked for navigational purposes. View obstruction could also be a concern, although many of the devices sit far offshore and would not be visible from land. 

Sea Power & Associates’ target market is remote coastal communities and small islands which now have to rely on diesel generators, which are expensive and dirty. Ocean power would produce no greenhouse gases and Cornes and Previsic believe their system could be cost-competitive with diesel, which they said now costs 18 cents to 25 cents a kilowatt hour. 

Sea Power & Associates got a boost this spring when their business plan won the $10,000 grand prize at the Social Venture Competition held at the University of California, Berkeley’s Haas School of Business. 

The next order of business is trying to squeeze money out of an increasingly skittish venture capital pool. 

“They’re still working ... which is a plus,” says Navarro. “I have to give a lot of credit to Mirko for believing in what they’ve done and pushing it forward.” 

Champ, too, hopes sea power is on the rise. 

“It just really is a crime to see this die,” he says. “Even if it only put a light bulb on the end of the pier for people to fish off, it would have been valuable. It would have been a light in the dark that didn’t cost anybody anything.”