The world’s first commercial wave farm started operating off the coast of Portugal at Agucadoura on Tuesday. It comprises three red “articulated sea snakes”, each about 140 metres long and 3.5 metres in diameter, which generate about 2.25MW of electricity – enough to power 1,500 homes.
Scottish firm Pelamis Wave Power made the wave converters. They are moored to the seabed about 5km offshore using a special system that allows the machine to float head-on into incoming waves. Each machine has a number of segments linked with hinged joints. As the machine moves with the waves, it extracts power from the motion of the joints. Each joint contains a hydraulic pump, which pumps high-pressure liquid through motors that drive power generators. (There’s a video of how it works on the Guardian’s website).
The energy is then transmitted to a substation on shore at Agucadoura by undersea cables. This energy is then supplied to homes via the national electricity grid.
Portugal has big plans for wave power. Another 22 “sea snakes” will be added to the Agucadoura project in the next few years, bringing its generating capacity to 21MW. This is enough for about 15,000 homes. “Portugal could be for wave power what Denmark was for wind,” a spokesman for Babcock and Brown, the company that built and commissioned the project, was quoted as saying.
As yet, wave power is too expensive to be competitive, reports say. The Agucadoura project’s first three wave converters reportedly cost 8.5-million euros. But the project was made possible in part by the Portugese government agreeing to a feed-in tariff which pays a premium for the wave-generated electricity. The developers envisage that in 15 years wave power should be as competitive as wind power is now.