No land stands between Antarctica and Australia’s west coast—just a vast ocean, rippled and rocked by the Roaring Forties. For centuries these westerlies, which blow between latitudes 40° S and 50° S, powered ships sailing from Europe to Asia. These days, they are also creating waves in the world of renewable energy. At the end of February, a demonstration project designed to use the ocean swell they produce went live. As a result Australia’s largest naval base now gets part of both its electricity and its fresh water courtesy of the ’Forties.
Carnegie Wave Energy, in Perth, has been working since 1999 on what it calls CETO technology. Ceto was the ancient Greek goddess of sea monsters, and Carnegie’s particular monsters are buoys that resemble giant macaroons. They float a metre or two below the ocean’s surface, bobbing up and down in the swell and generating electricity as they do so. The current version, CETO 5, has a capacity of 240kW per buoy. Three of the beasts are now tethered to the sea bed 3km from HMAS Stirling, on Garden Island. They also help to run a desalination plant on the base, for fresh water is a valuable commodity in Western Australia’s arid climate.
The buoys themselves are 11 metres across, made of steel and filled with a mixture of seawater and foam to give them a density slightly below that of water, so that they float. Being submarine means that, unlike previous attempts to extract power from waves, they are not subject to storms and the constant battering that life at the interface between sea and air brings. As Michael Ottaviano, Carnegie’s boss, observes, savvy swimmers in Australia know to dive under—not through—an approaching wave, to avoid getting smashed. The same applies to buoys.
Read more at The Economist