The $4 million in federal funds for the Navy’s Pacific Missile Range Facility for wave-powered, electricity-generating equipment would be better spent tapping ocean water for electricity and other resources, a University of Hawai’i researcher said. There are several drawbacks to
The $4 million in federal funds for the Navy’s Pacific Missile Range Facility for wave-powered, electricity-generating equipment would be better spent tapping ocean water for electricity and other resources, a University of Hawai’i researcher said.
There are several drawbacks to a system which requires length of shoreline to catch enough wave energy to generate substantial amounts of electricity, explained Dr. Hans Krock, a professor in ocean and resources engineering at the University of Hawai’i-Manoa.
“A larger resource by far is the ocean thermal energy resource,” which in part is energy stored as heat in the warmer, upper layer of the ocean, he said. “And Hawai’i is the world leader in that. We are not the world leader in wave energy.”
University researchers are already developing systems to use cold water from Pacific Ocean depths in waters around Hawai’i for air-conditioning systems, warm water from the upper layer to generate electricity and hydrogen as a future fuel, and various technologies to turn ocean water into drinking water, he explained.
“It’s commercially viable, because it’s a multi-product kind of thing,” producing water for agriculture and aquaculture systems now in place on Big Island and near PMRF at Ceatech’s shrimp farm between Kekaha and the base, Krock said.
Cooler water from ocean depths helps trick crops into thinking they’re in a temperate instead of tropical climate, and new uses for both the warm and cool ocean waters are being explored daily, he said.
Krock teaches a university class in ocean thermal energy conversion (OTEC) and is a professional engineer and holder of a doctorate degree in engineering.
The university and others in Hawai’i have been studying since the 1970s ways various temperatures of ocean water can be used for different purposes, Krock said.
Also in place in coastal areas in Europe and other parts of the world are wave-energy devices, one which generates enough electricity to power up to 700 homes.
A popular type of wave-energy system is called the Wells Turbine, after its inventor, which acts like an upside-down drinking cup, using the force of the wave pushing air through a hole in the bottom of the cup to power a turbine. When waves recede, the movement is tapped to generate electricity.
The Fiscal Year 2002 Department of Defense Appropriations Bill would include $4 million for a wave-energy system to generate electricity for PMRF, one of Kaua’i Electric’s largest customers.
PMRF stands to gain $127 million in Kaua’i defense initiatives inserted into the bill by U.S. Sen. Daniel Inouye (D-Hawai’i).
Among the problems with wave-energy systems, Krock said, are that:
– Large waves can damage the equipment.
– Waves are intermittent and seasonal.
– Once the system is installed, it can’t be moved to where the waves are.
– And because the length of shoreline facing the waves is sometimes long to generate lots of electricity, a nice stretch of beach sometimes may be dominated by the wave-energy collection device.
“Do we want to put these things along large stretches of our coastline? Apparently we don’t, because people want to have access to the beaches, and they want to have a picturesque coastline,” he said. “That’s why I’m saying that the best place to put this is someplace where you’re already altering the coastline, that is to say breakwaters.
“In general, along the coastline, I’m not sure that this would be a popular item to have. So it’s limited by the length of coastline that you’re putting it on.
“Is this going to be supplying energy to a large fraction of the island? No, I don’t think so.”
Staff Writer Paul C. Curtis can be reached at mailto:pcurtis@pulitzer.net or 245-3681 (ext. 224).
