Harnessing Waves and Tides
Around the world, powerful waves relentlessly pound the land while tides rise and fall in countless bays and inlets. Why not harness this renewable water power? Many engineers have asked this question, and today several projects are harnessing the never-ending power of tides and waves.
In 2006, beneath New York City's East River estuary, the energy of the tides began spinning a field of turbines, powering a nearby grocery store and parking garage. Each turbine spins slowly with the tide as it flows in, then turns around to capture power from the outgoing tide. Because tides are generated by the Moon's gravity tugging on Earth's oceans, they offer a reliable and inexhaustible power source. If the project goes well, the city could install hundreds more turbines.
The world's first commercial wave farm debuted off the coast of Portugal in 2006. Linked cylindrical generators, each about the size of a train car, wriggle back and forth in the waves. A resistance system inside each section generates the power. Three "wave snakes" could power 1,500 households.