Premises for an annual energy production and capacity factor improvement towards a few optimised wave energy converters configurations and resources pairs

Abstract

In the struggle against increasing global warming, wave renewable energy could help progress to the increasingly necessary renewable-based energy-mix. Wave energy has many applications, one of which involves its capture and conversion into usable energy. To date, there has been no agreement in the scientific community with respect to a single wave energy converter design, and given the numerous concepts involved, many approaches have been developed to investigate the performance of these different devices. This work summarises these approaches in addition to completing and extending them regarding wave spectrum, wave direction, generator capacity limitations, and use of the Froude similarity law for wave energy converter scaling. Ultimately, this study aims to improve the selection process of the most appropriate converter configuration for a given resource (i.e. wave distribution climate). The main results showed that neglecting the wave direction can lead to a 10 % energy production overestimation when the method is applied to the Wavepiston device. Furthermore, for Weptos and Wavepiston wave energy converters, different standard wave spectra were found to estimate the energy production with less than 8 % difference, below the 16.5 % estimated in previous studies. Additionally, the Reverse Froude Law method is introduced to help assess the applicability of the Froude similarity law for converter configuration scaling. Finally, a threshold in the decrease of generator capacity is determined such that, despite limiting the device power production potential, annual energy production remained almost as high as without generator limitations for an approximately 40 % capacity factor increase.