Statistical technique to improve the wave potential estimation for the design of wave electric generators

Abstract

• Wave measurements are used for the design and simulation of the electric generators. • The analysis is based on the joint probability distribution of height and period. • Fluctuations in wave power estimations, reduced; original core statistics, preserved. • The uncertainty in the generator’s electrical supply is reduced. • Year-long datasets recorded at a maritime buoy are used for realistic estimates. This study presents a statistical approach that allows estimating the sea wave power ( P max ) by using the joint probability distribution of the wave’s significant height ( H m ) and period ( T ), p H m , T . Unlike other works in the literature, the goal of the present paper is not to find the best locations for wave farming or to extrapolate the data in space or time, but to achieve a more suitable design of wave electric generators in terms of a reduced delivery uncertainty. When the raw values of H m and T are used, the estimations of P max end up spanning over several orders of magnitude owing to the nonlinear amplification of the fluctuations through the calculations. This typically results in large overestimations of P max that preclude their use for a modest design. Another associated issue is the low temporal resolution of the data available, which forbids using measurements of H m and T in numerical simulations directly. These issues have been overcome with the proposed methodology, whose core feature consists of generating a new series of random H m , T pairs, based on p H m , T , which allow estimating the wave power potential realistically while reducing the chances of over/underrating. In this new series, large fluctuations are suppressed, but the essential statistics of the measurements are preserved. Additionally, since the new series of H m , T pairs is time-independent, it can be fed directly into numerical simulations. To illustrate our proposal, we used one-year long datasets of hourly measurements of H m and T recorded at a maritime buoy, for the design and simulation of a linear electric generator with a single degree of freedom.