Snakes on a wave
When Nature (subscription) looked over the whole portfolio of carbon-free electricity options last month, it left wave power for last. In contrast to mature technologies like hydropower and up-and-coming ones like solar, most ideas for capturing the energy of pounding surf “remain firmly in the testing phase”, they wrote.
One project moving out of that phase involves three ‘wave snakes’ that the company Pelamis has just installed off the coast of Portugal - long, cherry-red tubes that wiggle in the waves and use the motion to drive generators, whose electricity passes onto the Portuguese grid. This video hosted by the Guardian shows how they work (and couples soothing music to the animated undulation - I may save the link for next time I’m up at night worrying about the energy crisis).
In the big picture, the wave snakes won't produce much power - just over two megawatts from the current three snakes, and 21 megawatts for the planned future array of 25 snakes, writes Alok Jha in the Guardian. The biggest existing hydroelectric dams are measured in gigawatts, and hundreds of megawatts is typical for a new coal plant. As noted in the Nature story, even exploiting waves the world over would probably yield much less energy than other alternatives. But wave power does make a novel addition to the assortment of technologies in play - as the Portuguese, who Jha reports are also pursuing solar and other renewables, seem to recognize.
Anna Barnett
Photo: A Pelamis wave energy converter during the final tests at the port of Peniche, Portugal; Guido Grassow
