Ocean motion power: aquabuoy and Wave Dragon sound like superheroes. Can they help save us from climate change?

Author:Jeffries, Elisabeth
 
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As every school child knows, the oceans cover most of Earth's surface. And as every blue-water sailor and hurricane victim knows, the power embodied in the waves and surging waters of the oceans is immense, often terrifying, and beyond human control.

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Kevin Banister knows all this, of course. But Banister, vice president in charge of marine power at energy project developer Finavera Renewables, believes that if control of the oceans is beyond us, harnessing at least some of their power is not. He is one of a coterie of entrepreneurs pioneering a new type of renewable energy that taps the endless motion of the waves. The ocean, he says, is "the world's biggest battery" and wave power "is an opportunity whose time has come."

The waves Banister hopes to conquer lie three kilometers off the Northern California coast near the small city of Eureka. In deep waters such as these (100 meters or more), the total power resource of the ocean waves is estimated at about 110 terawatts (billion kilowatts); by way of comparison, global installed electrical generating capacity in 2004 was less than 4 terawatts. According to the European Ocean Energy Association, mature technologies could tap an economically exploitable resource estimated at between 140 and 750 terawatthours per year. Theoretically possible improvements could drive that potential to as high as 2,000 terawatthours per year (global electricity generation in 2004, the latest year for which data are available, was 16,591 terawatthours).

Nevertheless, Finavera's project is a big gamble, even on the modest scale under consideration. The company aims to install devices of 2 megawatts' capacity to extract energy from the heaving motion of the seas, enough to power over a thousand homes. The movement, captured via an array of buoys, extends and contracts a hose that acts as a pump, forcing pressurized water through a turbine to generate electricity.

Banister has found a customer--the Pacific Gas and Electric Company--and concluded an agreement to start operations in 2012. He also wants to set up projects off the western coasts of South Africa, Oregon, Washington state, Portugal, and Canada. Like the Scottish company Pelamis, another wave power technology developer, Finavera has already run a prototype; Finavera's was in Oregon while Pelamis first tested its device in the Orkney Islands off Scotland. Denmark was the setting for tests of Wave Dragon, a third wave power device.

None of them has yet supplied electricity to a grid on a commercial basis nor set up a fully operational wave park, but they are leaders in a race to be the first to do so. Dates set for commissioning the projects range from 2008 to 2012. However, it is a very slow race already beset by false starts. In September 2007, after a six-month delay, Pelamis (the nominal front runner in the sector) had planned to connect three devices off Povoa de Varzim in Portugal in order to supply 2.25 megawatts' capacity to the Portuguese utility Enersis. As of spring 2008, not a single electron had been sent ashore.

The company blames the delay on weather conditions, seven-meter swells, and the technical intricacy of the operation. Fittings on and around its tubular devices, each about the length of five train carriages, have to be adjusted again and again over a period of time before commissioning, thus requiring a series of good weather "windows" while equipment is removed from the sea, adjusted to the altered specifications, and repositioned. While the delays are understandable in the context of an infant industry, the problems have already attracted critics.

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Dr. John Constable, a policy expert at the UK's Renewable Energy Foundation (REF), is skeptical of the project. "Waves are, frankly, not serious contenders [for marine power] at present, and in my view won't be so until there is a major breakthrough," he...

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