Ocean power surges forward
Wave power and tidal power are still experimental, but may be little more than five years away from commercial development.
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"It's really been a struggle, particularly since mid-September when Bear Sterns went down," Sauers says. "We worked without pay for a while, but we made it through."Skip to next paragraph
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Venture capitalists are not involved in ocean energy right now, he admits. Yet he does get his phone calls returned. "They're not writing checks yet, but they're talking more," he says.
When they do start writing checks, it may be to propel devices such as the Pelamis and the PowerBuoy. Makers of those devices, and more than a dozen wave-power companies worldwide, will soon vie to be among five businesses selected to send their machines to the ocean off Humboldt.
One of the major challenges they will face is "survivability" in the face of towering winter waves. By that measure, one of the more successful generators – success defined by time at sea without breaking or sinking – is the Pelamis, a series of red metal cylinders connected by hinges and hydraulic pistons.
Looking a bit like a red bullet train, several of the units were until recently floating on the undulating sea surface off the coast of Portugal. The Pelamis coverts waves to electric power as hydraulic cylinders connecting its floating cylinders expand and contract thereby squeezing fluid through a power unit that extracts energy.
An evaluation of a Pelamis unit installed off the coast of Massachusetts a few years ago found that for $273 million, a wave farm with 206 of the devices could produce energy at a cost of about 13.4 cents a kilowatt hours. Such costs would drop sharply and be competitive with onshore wind power if the industry settled on a technology and mass-produced it.
"Even with worst-case assumptions, the economics of wave power compares favorably to wind power," the 2004 study conducted for EPRI found.
One US-based contestant for a WaveConnect slot is likely to be the PowerBuoy, a 135-five-foot-long steel cylinder made by Ocean Power Technology (OPT) of Pennington, N.J. Inside the cylinder that is suspended by a float, a pistonlike structure moves up and down with the bobbing of the waves. That drives a generator, sending up to 150 kilowatts of power to a cable on the ocean bottom. A dozen or more buoys tethered to the ocean floor make a power plant.
"Survivability" is a critical concern for all ocean power systems. Constant battering by waves has sunk more than one wave generator. But one of PowerBuoy's main claims is that its 56-foot-long prototype unit operated continuously for two years before being pulled for inspection.
"The ability to ride out passing huge waves is a very important part of our system," says Charles Dunleavy, OPT's chief financial officer. "Right now, the industry is basically just trying to assimilate and deal with many different technologies as well as the cost of putting structures out there in the ocean."
Beside survivability and economics, though, the critical question of impact on the environment remains.
"We think they're benign," EPRI's Mr. Bedard says. "But we've never put large arrays of energy devices in the ocean before. If you make these things big enough, they would have a negative impact."