Wave Power
Wave power function by converting the energy of the
oscillations of the waves into electricity. Since the
oscillations of waves are for the most part always
happening, this method can produce power at almost all
times. There are a variety of different methods to do
so however each of which function in unique ways.The power available from waves is given by its power density which is the power per meter of wave crest can be found using a fairly simple formula.
(Taken from http://www.gov.scot/Publications/2006/04/24110728/10)
In this formula ρ is the density of the water, g is the gravitational constant, Hrms is the standard deviation of the water surface from its mean position, and Te is the period of the waves.
Point Absorbers
Point absorbers are located on the surface of the water and held in place by cables. They function by using the difference in height from wave oscillations to drive a hydraulic pump to create energy.http://energy.gov/eere/water/marine-and-hydrokinetic-technology-glossary
Surface Attenuators
Surface Attenuators work very much like point absorbers but are composed of a multitude of connected segments that are oriented perpendicular to the waves. They generate power by the flexing of the device around the joints connected the segments in order to drive a hydraulic pump.http://www.boem.gov/Renewable-Energy-Program/Renewable-Energy-Guide/Ocean-Wave-Energy.aspx