Is wave power in Hawai'i's future?
| • | Chart: From waves to energy |
By Jan TenBruggencate
Advertiser Science Writer
Wave power could be the next big thing in renewable energy, with a test project off Windward O'ahu expected to provide electricity as early as next month.
U.S. Navy photo
A power-generating buoy anchored north of Marine Corps Base Hawai'i near Kane'ohe already produced electricity — even during a period of relatively calm seas during testing in September — before being brought ashore for upgrades.
The mast of Ocean Power Technologies' wave power generating buoy is above the surface in Kane'ohe Bay, the working parts submerged.
The buoy, in 100 feet of water about seven-tenths of a mile north of the Mokapu Peninsula on which the Marine base lies, should be operating again in March.
The test system is one of three wave generators planned off Kane'ohe in the next year or two.
National research programs indicate wave energy is technically feasible and on the verge of being economically competitive with other forms of power generation.
The Electric Power Research Institute (EPRI) and the U.S. Department of Energy's National Renewable Energy Laboratory conducted studies off Waimanalo, as well as in the waters of Maine, Massachusetts, Oregon and California. Of those sites, the Hawai'i location had the best potential, said the agencies' report.
"Wave energy is an emerging energy source that may add a viable generation option to the strategic portfolio. The bedrock of a robust electricity system is a diversity of energy sources," said Hank Courtright, EPRI vice president for generation and distributed resources.
In Hawai'i, where 95 percent of electricity is produced from fossil fuels, nearly 90 percent from oil alone, a diversity of energy sources has long been a dream, but it has been slow in coming.
As of 2002, according to the federal Energy Information Administration, Hawai'i had a total electricity production capacity of 2,267 megawatts. Of that, only 173 megawatts, or 7 percent, was produced by renewable energy sources such as hydroelectric and wind power.
An average Hawai'i home draws 1 kilowatt — the equivalent of 10 lightbulbs rated at 100 watts each operating at once. In most homes, the power use is much higher at certain times — like when people are cooking, taking showers and watching television in the evening — and lower when people are asleep or at work or school.
The PowerBuoy, at an average output of 20 kilowatts, could produce enough power for 20 homes.
"We've been very supportive of geothermal, hydroelectric, biomass, solar and wind," said Maurice Kaya, director of the state's Strategic Industries Division. "There are obviously challenges to bringing wave power online. There are not only technical but environmental and siting issues, but we're very supportive of wave power."
The PowerBuoy systems being installed near Kane'ohe are built by Ocean Power Technologies of New Jersey. The systems comprise a buoy that hangs on a pole anchored to the sea floor and extending some distance above the surface so that ships can readily spot it. As swells pass, the buoy rises and falls like a piston, pumping hydraulic fluid to a hydraulic pump, which runs an electricity generator. The power is brought ashore by cable.
Ocean Power Technologies said the systems are anchored to the sea floor in ways that create minimal damage, and they can benefit anglers by attracting fishes. The company said an independent study in Australia indicated there is no harm to ocean life, including migrating whales.
There are numerous other designs of wave-power generation systems, most of them being tested in other countries.
If engineers get a period of calm weather next month, the initial PowerBuoy will be reinstalled off Mokapu and should quickly begin pumping electricity into the Marine base power grid, said Don Rochon, public affairs officer for the Naval Facilities Engineering Command Pacific at Pearl Harbor. The buoy has a maximum output of 50 kilowatts, but officials expect steady output in the 20-kilowatt range, depending on ocean conditions.
He said that first buoy and a second one expected to be installed by the end of the year are financed by a $12.9 million program of the Office of Naval Research. Rochon said he understands that money is being sought for a third buoy as well.
One goal of the wave-power effort is to find ways to make Navy ocean bases independent of fossil fuels for electricity production.
Rochon said the buoys are expected to be removed after two to five years of use, once sufficient data have been collected. More studies would be required if the military decided it wants them in place permanently.
Both EPRI and Ocean Power Technologies said small systems like these are hardly the most efficient. Much bigger systems provide the economies of scale that make them competitive with wind, oil and other sources of power.
The company said 20 PowerBuoys would have a maximum capacity of one megawatt.
Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.
