Small portion of ocean energy could meet world's needs: experts

If only 0.2 percent of the world ocean's untapped energy could be harnessed, it could provide power sufficient for the entire world, experts said on Wednesday.

Ocean energy, existing in the forms of wave, tidal, marine current, thermal (temperature gradient) and salinity, is one of the largest renewable and clean energy source, experts told the Energy Ocean 2006 conference in San Diego.

The meeting, organized by the U.S. Ocean Energy Council that promotes the utilization of ocean energy, presented the latest developments in oceanic power generation technology.

According to the scientists, there are some promising concepts to extract the energy in ocean.

One is wave generator, a buoy capable of transmitting wave energy into electricity, said a research team from the Oregon State University.

A full scale wave park buoy developed by the team, up to 10 meters tall and 6 meters in diameter, is able to produce 250 kw of power, supplying approximately 90 homes with power.

"Waves have several advantages over other forms of renewable energy such as wind and solar, in that the waves are more constantly available and more predictable, thus enabling more straightforward and reliable integration into the electric utility grid to provide reliable power," said Annette von Jouanne, a member of the team.

Wave energy also offers much higher energy densities, enabling devices to extract more power from a smaller volume at consequent lower costs, she added.

Similar to the wave generator is underwater tidal turbine, which generates renewable electricity from tidal currents.

According to James Ives, chief executive of the tidal turbine maker OpenHydro based in Ireland, tidal energy is expected to account for around 6 percent of Ireland's demand in 2010.

The company is developing an open-center turbine connected with power grid in Irish waters for installation during this year, Ives said.

Another form is the so-called "windfarm," offshore or onshore windmills that utilize strong sea breeze to generate power. Several windfarms have been running well in the United States and Europe, experts told the meeting.

A windfarm of 18 turbines on Plum Island, New York, produces 8 megawatt of power, said Bill Wall from the Caldwell Marine International. The windfarm not only supplies power for the Animal Disease Center, but also sells surplus electricity to local power firms.

Some scientists plan to extract energy of oceanic currents with the help of an oscillating wing or other working bodies. The technology, called "Vortex Induced Vibrations" (VIV), converts the energy of flowing water into usable energy without spoiling the flow.

Experiments performed at the University of Michigan have "met and often exceeded expectations," said Tad Dritz, a researcher from the Vortex Hydro Energy LLC.

The concept of VIV has won support from the U.S. Department of Energy for further development, he added.

Source: Xinhua