There are growing provisions to include ocean wave energy as an alternate renewable energy source. There are also several challenges that need to be addressed before the technology gains full engineering and market confidence. One of the main technical hurdles is the need to address part-load problems of wave energy converters resulting from bathymetric conditions and variations in wave parameters such as wave frequency and height. As such, the wave phenomenon is inherently variable in time and space. This is compounded by the fact that wave energy conversion devices are less efficient at part load. This paper discusses Sources of part loads in wave energy conversion including their impact oil system efficiency for a California weather scenario, also relating wave energy conversion techniques to part-load efficiencies.