SHAVE ICE
By TOM STEVENS, For The Maui NewsOur target is to
harness indigenous
and renewable energy
sources and make
this a glowing example
to the world.
— Peter Kalish,
wave-energy proponent
Like many scientific breakthrough tales, this one starts with an almost accidental realization: a “eureka moment.”
In 1993, the story goes, an oceanographer named Tom Denniss was standing near a blowhole on Australia’s east coast. As blowholes do, this one shot a powerful blast of spray skyward as each incoming swell compressed the air trapped beneath a rock ledge.
Unlike other curiosity seekers who gazed at the world’s various blowholes that day, Denniss had an agenda. He was trying to figure out how ocean swells could generate electricity.
It wasn’t a new idea. All sorts of Nemo-esque schemes already had been proposed — gigantic piston pumps, bladed tidal waterwheels, even a hydraulic “snake” that would lie on the ocean floor and thresh the swells through 700 tons of linked articulating cylinders.
However ingenious and futuristic these designs, they all suffered the same shortcoming: too many moving parts underwater. If corrosion didn’t doom these machines, resistance stress eventually would.
As Denniss watched the Australian blowhole send blasts of spray ripping into the sky, he realized those jets of air could spin the blades of a turbine. Eureka! Why not create a “portable” blowhole and mount a turbine over it, out of the water? Denniss hurried back to his garage to do the calculus.
Fifteen years and $35 million later, Denniss’ aha! moment has begotten the Oceanlinx Mark I, a 500-ton floating “wave energy” generator that could become part of Maui’s future energy mix. Negotiations are now under way to tether a prototype Oceanlinx unit a half-mile seaward of East Maui’s Pauwela Point lighthouse.
As company spokesman Peter Kalish told a curious Kahului audience last Thursday night, the ocean power unit would sit far enough offshore and in deep enough water (100 feet) to avoid being hammered by breaking surf. Rather, the boxy unit would use the rise and fall of ocean swells to propel air through a variable-pitch turbine-blade assembly. This in turn would generate electric current that could be cabled ashore and added to Maui’s power grid.
The swells wouldn’t have to be big, Kalish said, adding that an Oceanlinx prototype moored 50 miles south of Sidney has been generating electricity from swell surge as small as 2 to 3 feet.
“We can produce electricity in swells under a meter high,” he said. “The air trapped in our oscillating chamber drives a turbine, and a cable carries the energy onshore. There are no moving parts in the water. Nothing that will harm any form of marine life.”
If it can navigate a 12-month environmental impact review successfully and survive 18 months of negotiations with the state’s various electric companies, Oceanlinx plans to have its first Hawaii unit in operation at Pauwela by late 2009.
The $20 million ocean power generator would produce 2.7 megawatts of electricity, Kalish said, enough to power about 500 homes. Because the generators have a small “parking space,” Kalish said, “10 to 20 wave units could be compacted together” to power as many as 10,000 Maui homes in the future.
A video clip of the Oceanlinx prototype south of Sidney showed a boxy-looking metallic vessel that could have sprung from the loins of those Civil War ironclads, the Monitor and the Merrimac. As the swells pushed trapped air through its chimneylike “oscillating chamber,” the device issued soft, regular, slightly melancholy moans, like a lovesick sea monster yearning for its mate.
“These units are very quiet,” Kalish said. “They emit only 75 decibels, less noise than a vacuum cleaner.”
In addition, the Oceanlinx units can double as “water farms,” he continued, by using their power-generation capability to desalinate seawater. Ideally, linked units could produce as much as a million gallons of drinking water per day, he said, to be pumped ashore through a 6-inch-diameter pipeline.
Finally, each floating offshore energy platform likely would become a “fish-aggregating device” like the state fish buoy anchored off Hana. “It would be a boon to fishermen and divers,” Kalish suggested.
Despite its seeming versatility, the system will function only in certain global “wave climates,” he said, where swell energy tops 15 kilowatts per meter. “Equatorial seas are too calm; they won’t work.” As luck would have it, Maui’s north shore fits the bill, as do numerous other open-ocean coastlines worldwide.
“We’ve been talking with energy planners in Rhode Island, Portugal, Namibia, Baja Mexico and Australia,” Kalish said. “But Maui is our top-priority project. We’re determined to make this one a showpiece of the world.”
Oil recently reached $100 a barrel. Eureka! This might be worth a look.
• Tom Stevens is a freelance writer whose “Shave Ice” column appears every Wednesday. He can be reached at shaveice@maui.net.
