Construction has begun off Oregon's coast on the first commercial U.S. wave-energy farm, planned to supply power to about 400 homes, according to a USA TODAY report. Wave power draws from the energy of ocean surface waves. A float on a buoy rises and falls with the waves, driving a plunger connected to a hydraulic pump that converts the vertical movement into electricity. The first buoy will measure 150 feet tall by 40 feet wide, weigh 200 tons and cost $4 million,  according to Phil Pellegrino, spokesman for New Jersey-based developer Ocean Power Technologies, which is developing the project.