The Use Of Wave Focusing Technologies For Wave Energy Conversion Applications

A study by the Electrical Power Research Institute and U.S. Department of Energy (DOE) reported an estimated total available wave energy resource of 2,640 terawatt-hours (TWh) per year and total recoverable wave energy resource at 1,170 TWh per year for the territorial waters over the Outer Continental Shelf of the United States in 2011[1]. While Wave Energy Conversion (WEC) systems have been in development since the first patent in 1799, the industry is still in its infancy globally and large commercial deployments have still not taken place. A key challenge for the commercial viability of WEC systems is effective extraction of the kinetic energy in waves by the power takeoff systems. Since the wave form and motion are critical factors influencing the kinetic energy input to WEC power takeoff systems, increasing the wave steepness acting on the WEC body can significantly enhance the velocities of water particles impacting prime movers and increase power takeoff performance. The use of variable-depth platforms to enhance wave steepness and increase power takeoff performance through increased kinetic energy input to prime movers is a novel idea that provides promise for increasing the capacity factor for WEC systems. The application of a variable-depth platform to wave energy conversion is discussed and quantified based on wave tank testing, wave theory, and the kinetic energy equation.