Tidal' energy' wave of future

Bendigo Advertiser
Wednesday 15/11/2006 Page: 25

In the quest for oil-free power, American companies are staking claims on the boundless energy of the sea.

THE technology that would draw energy from ocean tides to keep light bulbs and laptops aglow is largely untested, but several newly minted companies are reserving tracts of water from Alaska's Cook Inlet to Manhattan's East River in the belief that such sites could become profitable sources of electricity.

Tidal power proponents liken the technology to little wind turbines on steroids, turning like windmills in the current. Water's greater density means fewer and smaller turbines are needed to produce the same amount of electricity as wind turbines.

After more than two decades of experimenting, the technology has advanced enough to make business sense. In the past four years, the Federal Energy Regulatory Commission has approved nearly a dozen permits to study tidal sites. While applications for about 40 others are under review, no one has applied for a development licence.

The site that is furthest along in testing lies in New York's East River, between the boroughs of Manhattan and Queens, where Verdant Power plans to install two underwater turbines this month as part of a small pilot project. Power from the turbines will be routed to a supermarket and parking garage on nearby Roosevelt Island.

The six-year-old company will spend 18 months studying the effects on fish before putting in another four turbines. The project will cost more than $US10 million (about $A13 million), including' $U82 million ($A2.6 million) on monitoring equipment.

If all goes well, New York-based Verdant could have up to 300 turbines in the river by 2008 which would produce as much as 10 megawatts of power, or enough electricity for 8000 homes.

With 19,919km of coastline, the US may seem like a wide-open frontier for the fledgling industry, but experts believe only a few will prove profitable, like those beneath San Francisco's Golden Gate Bridge and in Knik Arm near Anchorage. These ideal sites are close to a power grid and have large amounts or fast-moving water with enough room to build on the sea floor while staying clear of boat traffic.

But Europe, Canada and Asia have moved faster than their US counterparts to support tidal eneyrgy with small facilities in Russia, Canada and China, as well as a 30-year-old plant in France.

In the United States, wave energy technology is less advanced than tidal and will need more government subsidies, however, the number of good wave sites far exceeds that of tidal. Wave power collection involves cork or serpent-like devices that absorb energy from swells on the ocean's surface, whereas tidal machines sit on the sea floor.

Tidal energy technology has been able to build on lessons learned from wind power development, while wave engineers have had to start virtually from scratch, but a few companies are working aggressively to usher wave power into the energy industry.

One of these is Aqua Energy who could start building a wave energy plant at Makah Bay in Washington state within two years. Another wave plant is under construction off the coast of Portugal.