Layouts for ocean wave energy farms: Models, properties, and optimization

Abstract

Renewable energy, such as wave energy, plays a significant role in sustainable energy development. Wave energy represents a large untapped source of energy worldwide and potentially offers a vast source of sustainable energy. We present models and a heuristic algorithm for choosing optimal locations of wave energy conversion (WEC) devices within an array, or wave farm. The location problem can have a significant impact on the total power of the farm due to the interactions among the incident ocean waves and the scattered and radiated waves produced by the WECs. Depending on the nature of the interference (constructive or destructive) among these waves, the wave energy entering multiple devices, and thus the power output of the farm, may be significantly larger or smaller than the energy that would be seen if the devices were operating in isolation. Our algorithm chooses WEC locations to maximize the performance of a wave farm as measured by a well known performance measure called the q-factor, which is the ratio of the power from an array of N WECs to the power from N WECs operating independently, under the point absorber approximation. We prove an analytical optimal solution for the 2-WEC problem and, based on the properties of the 2-WEC solution, we propose an iterative heuristic optimization algorithm for the general problem.

Experimental Validation of a Wave Energy Converter Array Hydrodynamics Tool

“…In the laboratory, the PTO was required to behave as a linear damper, i.e., the moment exerted by the electric motor was targeted to be directly proportional to the angular velocity (see Section 3). Even though more sophisticated control strategies may be used to improve performance of WECs, the simple implementation of linear damping control makes it suitable for full scale WECs and also applicable to most WEC designs; therefore, it has been generally used in numerical models as the control strategy for a generic WEC and for WEC arrays, such as in [8][9][10][11][12][13] and in [16]. Additionally, and unlike other types of PTO systems, such as Coulomb dampers, linear dampers allow the physical model parameters and results to be scaled, as mentioned before, through Froude's scaling law.…”

“…The effect of the friction in the linear motor was observed to have a short duration; thus, having a negligible effect on the mean absorbed power (Equations (12) and (17)). In the laboratory, the PTO was required to behave as a linear damper, i.e., the moment exerted by the electric motor was targeted to be directly proportional to the angular velocity (see Section 3).…”

“…The effect of the friction in the linear motor was observed to have a short duration; thus, having a negligible effect on the mean absorbed power (Equations (12) and (17)). …”

Modeling Link for Ocean Wave Energy of Point Absorbers: A Mathematical Framework

“…The triangle configuration itself turns out to be the a suitable choice in terms of Wave Energy extraction for small arrays according to literature [41,51]. Out of this recent references it is also worth to investigate results for greater arrays.…”

“…This way, f becomes √ 11.25r, keeping the bodies more stretched in the x-direction than in the y one. The reason for choosing latter cases relies on the results determined by [39,40], which refer to that triangular and squared/diamond array layouts as fairly suited for Ocean Wave Energy extraction [41].…”