Wave energy has a more general application, with potential along the California coast. Wave energy conversion takes advantage of the ocean waves caused primarily by interaction of winds with the ocean surface. Although many wave energy devices have been invented, only a small proportion have been tested and evaluated. Furthermore, only a few have been tested at sea, in ocean waves, rather than in artificial wave tanks. There are currently more than 12 generic types of wave energy systems.
Some systems extract energy from surface waves.
Others extract energy from pressure fluctuations below the water surface or from the full wave. Some systems are fixed in position and let waves pass by them, while others follow the waves and move with them. Some systems concentrate and focus waves, which increases their height and their potential for conversion to electrical energy. A wave energy converter may be placed in the ocean in various possible situations and locations. It may be floating or submerged completely in the sea offshore or it may be located on the shore or on the sea bed in relatively shallow water.