An Australian company will build off the coast of Maui a wave power plant capable of producing 2.7 megawatts of electricity from the rising and falling of the ocean. (Images: (top to bottom) What the Oceanlinx platform will look like on the surface, how it works, how the power gets to shore. Graphics courtesy Oceanlinx and Hawaiian Electric.)
Oceanlinx has a technology that allows the waves to force a column of air through a turbine. A rising wave shoves the air through the turbine one way. A falling wave sucks it through the turbine the other. It's designed so the turbine keeps turning in the same direction.
(For more information see www.oceanlinx.com.)
The Oceanlinx system is just one of a broad range of wave power systems. Some are fixed to the coastline, sucking energy from the crashing of waves on the land. Others use big submerged buoys that bob up and down in the water column. Others have floaters on the surface. And there are lots more.
An existing system off the Marine air station at Kāne'ohe, operated by Ocean Power Technologies, uses its PowerBuoy system, in which mostly submerged buoys create electricity as they are rocked up and down by the waves. (For more information see www.oceanpowertechnologies.com.)
“Ocean energy today is where wind was 15 to 20 years ago—with many competing technologies,” said Michael May, president of Hawaiian Electric.
The $20 million Oceanlinx system is to be built more than half a mile from shore 
at Pa'uwela point in Maui's Ha'ikū district. The company is performing its environmental studies, and hopes to have three wave platforms installed and working by the end of 2009.
Maui Electric has agreed to buy the power, although a formal purchase power agreement has not yet been completed. The cost of the system will be borne by Oceanlinx and investors, and a Hawaiian Electric unregulated subsidiary, Renewable Hawaii Inc., has signed a memorandum of understanding to possibly invest in it.
Oceanlinx says that among the benefits of its wave system is that it can be used in many different depths of water, has few moving parts and can be readily scaled up by adding units.
A seafloor power cable carries the energy from the moored units to the island.
Hawaiian Electric's May credited state Rep. Cynthia Thielen with being a persistent voice in support of ocean energy. Oceanlinx chairman David Weaver said he hopes the technology will be expanded to other parts of Hawai'i.
“The Oceanlinx technology is an ideal fit for Maui, with its excellent wave climate, and we hope to be able to continue working with Hawai'i on wave energy projects in the future,” Weaver said in a press release.