"Ocean Powered Technologies is the first company to commercialize wave energy. They have designed massive buoys that bob in the ocean with the waves. A piston sliding up and down in the buoy generates the energy and a complex computer system inside converts it into an endless source of electricity. The source is endless because unlike other sources like oil or fossil fuels, waves are there continuously.
One buoy can power about 150 homes, and that's why they are developing wave parks with hundreds of buoys. Cables dropped from the bottom run to shore where they plug into a power grid. The first wave park to power a city was just deployed off the coast of Spain. A wave station is also under development to help power the state of Oregon in 2009. There's also a buoy getting tested right now in the factory in Pennington NJ, that'll be moved into the ocean 70 miles east of Atlantic City. It will power naval surveillance equipment.
The buoys have to be within 3 miles of the shore to work, but since they are mostly submerged, they are hardly noticeable from the beach. What's the environmental impact? Studies have shown it's safe to underwater life, has no harmful emissions, and is noiseless." quoted from cbs3.com article
Ocean Power Technologies' PowerBuoy® is designed to convert ocean wave energy into useable electrical power for utility-scale grid connected applications. The PowerBuoy® can be deployed in arrays scalable to 100’s of megawatts