Session: 09-02-03 Wave Energy: WEC Arrays

Paper Number: 123655

123655 - Improving the Wave Energy Production Using Multi-Size Wec Arrays With Passive Control 

One of the key aspects to consider before large scale deployments of wave energy converters (WEC), is to optimize the devices’ characteristics to improve wave power absorption. Typically, devices with passive control are designed to have the highest efficiency in wave power absorption/production in the range of the most frequent wave conditions. On the other hand, with the help of active response controls it is possible to keep high efficiency within a larger range of wave periods. This technology also makes the WEC design more expensive. In general, there is an intrinsic “trade-off” between the range of wave conditions where a WEC can operate and the operation efficiency which, in the end, is linked to the energy production yield. Outside the most frequent wave conditions, there is still a non-negligible percentage of occurrences of more energetic sea states carrying high energy flux values. Given the specific design characteristics of a WEC device, lower operation efficiency is expected during these stronger sea states, which is translated as a lower production compared to the available (usable) resource.

In the present study, a multi-size point absorber WEC array, using passive internal control, is proposed to optimize wave power production at the array level. The main aim of this work is to verify the combined use of devices designed to work in the most frequent wave conditions, with WECs which mass and dimensions are defined to improve their response during stronger sea states. A comparison of the mean produced power is performed between a proposed multi-array and a single size one. This is done using 20 years of spectral wave data obtained from an implementation of the WAVEWATCH III model, while response of the wave energy converters array is simulated with the boundary element model HAMS-MREL. Finally, a brief analysis on the production downtime is performed to assess the potential effects of extending the devices’ operation limit to larger wave heights.

Presenting Author: Matias Alday Delft University of Technology

Presenting Author Biography: Matias is a Civil Engineer from Universidad Técnica Federico Santa Maria (Chile). After 8 year of consulting/research projects in coastal an port engineering, and teaching activities in Universidad de Valparaiso within the Ocean Engineering School, he obtained his M.Sc in Physics of the Ocean and Climate at Université de Bretagne Occidentale (Brest, France) between 2016 and 2017. He then worked as a research engineer at Ifremer before obtaining his Ph.D in Physical Oceanography (also at the Université de Bretagne Occidentale). Currently he works as a Postdoc researcher in the Marine Renewable Energies Lab (MREL) at the Delft University of Technology. Most of his research work has been focused on characterization of the sea states mixing numerical modelling and remote sensing techniques. In recent years his research interests have expanded to marine renewables (mainly waves and tidal), including studies on uncertainties in the resource estimation, absorbed power estimations and energy production.

Authors:

Matias Alday Delft University of Technology
Vaibhav Raghavan Delft University of Technology
George Lavidas Delft University of Technology