By Jan TenBruggencate
Advertiser Staff Writer
When it comes to potential nonfossil fuel energy in Hawai‘i, ideas are not in short supply.
Several have been tried and may have potential as significant sources of energy in the Islands. These include fields of solar panels and ocean thermal energy conversion — creating electricity by taking advantage of the differences in the temperature of surface ocean water and deep water.
There are techniques that are providing the Islands with significant electricity, such as a couple of fields of wind machines, and geothermal — using the heat of Hawaiian volcanoes to produce energy.
Hydroelectric power is not a major source, although there are hydro plants on several islands, in part because of the effect on stream life and on the appearance of Hawaiian waterfalls whose flows would be reduced by diverting rivers into pipes.
At least one researcher has suggested building underground dike systems to block the flow of groundwater from the uplands toward the ocean, and running the backed-up water through turbines.
O‘ahu resident Larry Blanchard figures that the ocean currents that flow past the Islands are a power resource that could be harnessed, using several thousand slow-turning sea-floor turbines.
"The shape of the blades will minimize trauma to ocean animals, there will be little or no pollution, and best of all, they will be out of sight — no ugly windmills. At 30 percent efficiency, 8,000 100-foot-wide submerged turbines could supply 600,000 kilowatts. This would supply about 200,000 homes or about 1 million people," Blanchard said.
He also likes the idea of using the dissolved carbon compounds in seawater, combined with hydrogen, to create methanol for use as fuel.
Various concepts have been advanced over the years, in Hawai‘i and elsewhere, to take advantage of ocean swells and coastal waves to generate power. Now a Scottish company, Wavegen, has built a working plant.
The system uses a concept familiar to Islanders from the Halona blowhole and Kaua‘i’s Spouting Horn, in which a wave enters an subsurface chamber and air (along with some water in the cases of these natural blowholes) is forced at great pressure out of a small hole. Wavegen’s plant runs the compressed air through a turbine.
"Wave power has joined the important group of commercially viable, competitive and clean forms of sustainable energy; this is the launch of a new global market," said Wavegen managing director Allan Thomson when the system on Scotland’s Isle of Islay, began operation last November. For more information, see www.wavegen.com.
Jan TenBruggencate is The Advertiser’s Kaua‘i bureau chief, and its science and environment writer. You can call him at (808) 245-3074 or send e-mail to jant@honoluluadvertiser.com.
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