Wave Energy Enhancement for Nearshore Electricity Generation

Sea waves carry 103 – 104 gigawatts (GWs) of power. Although there are a large number of different approaches to harness offshore wave energy they could be expensive, practically challenging and vulnerable to storms. Therefore, this paper explain how nearshore waves could be used and converged to increase the energy density and generate electricity using a smaller wave energy converter (WEC) than would otherwise be necessary. To illustrate the effectiveness of this approach, some tests were carried out with a physical model of a manipulator both in steady, uniform waves and in random waves created in a wave flume representing different sea states. The results include comparisons between theoretical predictions and wave flume tests with respect to incident wave energy, loss in manipulation and increase in energy density for different settings of the manipulator. The paper also presents the brake torque and angular velocity of two single duct, axial flow turbines placed in manipulated waves. It is found that wave manipulation creates energetic off shore waves close to nearshore which makes it suitable for typical offshore WECs. The paper also discusses morphodynamics and ecological issues and outlines the advantages of building coastal structures for wave manipulation.