The ocean is a tremendous storehouse of energy and non is more abundant than in its surface waves. Making use of this potential for electrical energy involves mainly the harnessing of the up and down motion of a flowing wave. This motion can be made to act on a hydraulic column or force contained air through turbine blades to produce rotational mechanical power. This mechanical power is then spins an attached generator and thus produces electrical power. (See an illustration here).
The calculations done here are based on the average HC locations coastal power equivalent potential of KW/km [ KW/mi] (based on this data map) and adjusted to reflect the fact that open water waves are tens of times more powerful than coastline waves due to the greater water depth. A very minimal factor of X was chosen here. Due to the size/power limitations of a generating device or facility, such a wave would have to be tapped into more than one time in order to extract most of its potential power. In this case ten times.
Wave Energy Systems
U. Of Michigan- OWC Design
Wave Power FAQ May 28, 2008