Conference article

The near shore Oscillating Water Column (OWC) based wave energy plant shows enormous promise for the commercialization of wave energy. The design details of such a plant; with an average incident energy of 24 kW/m and capable of producing 100 GWh over a two year period are described. The caisson; which could be a part of a breakwater; is constructed in a modular fashion in widths of 20 m. The power module is built around a 4.5 m diameter twin unidirectional impulse turbine with a rating of 900 kW. A key feature of the design is to combine the output from several OWCs into a single power module. Simulations show that the efficiency of the turbine can exceed 60 % from 10 to 100 % of the rated power. It is shown that a breakwater length of about 660 m with 11 such turbine generators is sufficient to meet the design requirement; with an overall wave to wire efficiency of about 36 %. The power electronics interface to the grid could be implemented with doubly fed induction generators or variable speed synchronous generators directly obtainable from the wind power industry. Laboratory experiments on a model turbine are used to validate the main claims.

OWC; twin unidirectional turbine topology; doubly fed induction machine