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Analysis and Technology

Pioneering wave power farm renews green energy hope

After a series of false dawns, the world's first commercial wave farm is to open soon. Will this be a fresh start for the technology?

By Hal Hodson

22 May 2013

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Awash with energy

(Image: Phillipe Lesprit/Plainpicture)

WAVE energy hasn’t had a great time of it in recent years. Despite advances in research, getting wave power up and running in any meaningful commercial sense has not been very successful – and that’s putting it mildly.

In 2008, for example, the world’s first commercial plant, based on a system by Pelamis of Edinburgh, UK, opened to great fanfare off the coast of Portugal. But the project was cancelled two months later amid technical and financial problems.

Wave power is to get another bite of the cherry when a commercial wave farm opens off the coast of Italy next month. The farm, the first of its kind, will use an approach that eschews the heavy swells favoured by previous systems and aims to make it possible – and cheap – to harness the surf along previously unviable coasts.

Wave energy companies have typically focused on the most energetic seas – off the wild coasts of Scotland, for example. But Michele Grassi, founder of London-based wave energy company 40South Energy, says this means building expensive, bulky platforms which can survive powerful storms. In contrast, 40South’s machine does not try to endure extreme conditions – it hides beneath them.

“The machine does not try to endure extreme wave conditions – it hides beneath them”

On 19 June, 40South will install a 150-kilowatt module outside Livorno Port in Tuscany. The machine uses two connected buoyant sections that sit one above the other at different depths, with the lower one moored to the seabed. The arms that connect them move inside each other like pistons, generating power using electric dynamos as they move. The whole structure sits below the surface, where wave energy can still be captured but at lower amounts. Crucially, it automatically adjusts its vertical position in the water depending on the conditions, sinking out of harm’s way during large, potentially damaging storms. This also helps it produce consistent levels of power.

The steady output is a big advantage, says Hugo Chandler of London-based energy consultancy New Resource Partners, whose work focuses on integrating renewable power into the grid. “Something more stable is much less frightening for the grid operator,” he says. “They’re going to get a cheaper grid connection.”

Wave energy researcher Ted Brekken at Oregon State University in Corvallis says it was natural for wave energy companies to initially try to harness the most powerful waves possible, but pursuing the most energetic waves at any cost doesn’t necessarily make sense. “How much it costs to make, maintain and deploy the device is very significant for wave energy,” says Brekken. This seems to be the way forward. Indeed, Pelamis claims its latest design, called the P2, costs less than its predecessor and is simpler to build.

Italy’s largest power company, Enel, bought the Livorno Port unit from 40South last year, and has an agreement to buy more if all goes to plan, as part of a five-year partnership. Carlo Papa, chief innovation officer of Enel subsidiary, Enel Green Power, says the firm spent months on the lookout for marine energy technologies that were safe and easy to manage, and which had no impact on the existing marine environment. “We’ve seen a lot of the machines that are out there,” Papa says. “40South weren’t lucky, they were good.”

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