Intra-annual variability in the performance of an oscillating water column wave energy converter. (1st March 2020)

• Record Type: Journal Article
• Authors: López, I.; Carballo, R.; Iglesias, G.
• Is Part Of: Energy conversion and management. Volume 207(2020)
• Publication Date: 2020-03-01
• Subjects: Oscillating water column -- Physical modelling -- Air compressibility -- Numerical modelling -- Wave energy -- Turbine-induced damping; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2020.112536
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: The intra-annual variability in the performance of OWC converters is evaluated. A hybrid methodology combining numerical and physical modelling is used. The intra-annual variability in the performance of an OWC exceeds 20% The damping maximising the OWC performance changes on a monthly basis. An intra-annual analysis is crucial for accurately dimensioning an OWC turbine. Abstract: The intra-annual variability in the wave resource is often disregarded when analysing the performance of wave energy converters (WECs), despite the fact that this variability is substantial in the majority of the areas of interest for the development of wave energy. The objective of this work is to analyse and quantify the intra-annual variability in the performance of oscillating water column (OWC) WECs through a case study in Galicia (NW Spain). To this end a three-step methodology which combines numerical and experimental modelling is followed: (i) intra-annual wave energy resource matrices are determined numerically through a high-resolution procedure; (ii) efficiency matrices of the device are determined by means of physical modelling, considering the influence of air compressibility and different turbine specifications represented through different values of turbine-induced damping; and (iii) finally, intra-annual energy capture matrices are calculated by combining the resource and efficiency matrices. It is found that the intra-annual variability in the energy capture of an OWC converter is significant, over 20% in the case study considered, albeit slightly smaller than that of the wave energy resource itself. The turbine-induced damping exerts a modulating effect over the variability in the intra-annual captured energy. Furthermore, the optimum damping which maximises the performance of the OWC converter varies from month to month.