Catching the Energy Wave

Pioneers are learning to tap the ocean's power

By Victoria Schlesinger

The planet’s oceans have gone by many names, but only recently was World’s Biggest Battery added to the list. But it makes sense. As we wrestle to limit our fossil fuel use, the ocean’s immense power is an obvious alternative. The question is how to harness and convert all that energy into something people can use.

Among the many trying to find an answer is Finavera Renewables, a Canadian renewable energy company that just completed a pilot project, employing a buoy to capture wave power off the coast of Newport, Oregon.

Bobbing like a cork on the Pacific Ocean’s surface, the 72-foot-long buoy rises and falls with the swell of each wave, pushing a piston, which in turn forces water to rotate a turbine. The buoy’s electricity is connected to the mainland by an undersea cable that runs two and half miles from the shore.

But before Finavera completed its pilot at the end of October, the buoy unexpectedly sank. Nonetheless, Kevin Bannister, Finavera’s VP of business development, called the test a success. “It delivered the data that we wanted,” he said. “We basically proved that we have an idea that’s going to work.”

The challenge now is to retrieve the contraption, figure out what went wrong, and begin designing a larger version of it.

Finavera’s pilot project may well be the embodiment of where wave power technology currently stands: a wealth of ideas, model projects, and entrepreneurs determined to overcome some significant challenges. The company is just one of dozens worldwide racing to develop the most efficient and cost effective means of capturing wave energy. And there’s good reason for it. According to the Department of Energy, the ocean’s waves provide up to two terawatts of electricity. The entire world currently consumes ten terawatts.

But our efficiency for capturing the energy of a surface wave’s up and down motion is still quite low, in part because the search only began three decades ago with a design by Stephen Salter. An engineering professor at the University of Edinburgh, his model, known as “Salter’s Duck”, was theoretically very efficient, but was never built because of high costs.

Today, a slew of different methods are being tested, and among the most promising is the buoy.

New Jersey-based Ocean Power Technologies has been testing buoy technology since the mid-1990s and recently agreed to build a wave farm project off the coast of Reedsport, Oregon, in collaboration with a local power company, Pacific Northwest Generating Cooperative. It will first test a 150-kilowatt prototype buoy and then expand to 2 megawatts (MW).

Another approach involves long, snaking pontoons floating on the ocean’s surface. As the “snake’s” jointed parts move with the waves, they drive hydraulic motors. A Scottish company called Pelamis Wave Power produces the devices, four of which will be used in a 3MW project off the coast of Orkney expected to be operating by 2008. Variations on an oscillating water column, which uses waves to compress air and then move a turbine, are also promising.

How best to deliver the electricity to the mainland’s power grid is another pressing question—one the British government has recently taken on. The government approved plans for a $52 million project in September to build a “wave hub” off the coast of Cornwall in South West England. Positioned 10 miles from shore, the hub will support 30 pilot projects, including the technologies mentioned above, by connecting their electricity to the mainland. It will cover an area measuring two and half miles by one and quarter miles and should be functional by 2009.

While the potential for wave energy is great, the limits remain significant. Like renewable wind and solar energy, wave power is optimal in select regions—particularly the western coasts of Scotland, northern Canada, southern Africa, Australia, and the northern coasts of the US. Also, the very power we’re attempting to capture can wreak havoc on equipment, and hearty, sea-worthy materials and structures are costly.

But from a pollution and emissions perspective, wave power looks pretty good. In Finavera’s case, there’s no CO2 emitted, no fuel needed, and in the face of mishap, there’s no danger of massive toxic spills. The company intends to retrieve its prototype from the bottom of the ocean, but for pioneers, even this is data. “It’s easy to see the silver lining,” Bannister said, “because it’s an additional learning moment for us.”