Control of Oscillating Water Column (owc) Wave Energy Plants

Wave energy composes a direct and easy way of harnessing power from the Ocean. Among the different techniques used, OWC devices stand as one of the most promising ones. NEREIDA MOWC demonstration project is a breakwater wave plant located in the Basque location of Mutriku, using Wells turbines and Doubly Fed Induction Generators (DFIGs). Since one of the main objectives when dealing with renewable energies is to make them economically viable to compete with fossil fuels and nuclear fission, all technological improvements are particularly welcome. In this context, this paper presents a control scheme for OWC wave power generation plants that allows to avoid the undesired stalling phenomenon present in Wells turbines. The proposed controller does appropriately adapt the rotational speed according to the pressure drop entry. The results show that the system avoids the stalling behaviour and that the active power of the generator fed into the grid is significantly higher in the controlled case than in the uncontrolled one.