Nowadays the goal of WEC developers is to reduce the price of the harvested energy for its own technology, via either decreasing the cost of WECs or increasing the power production. In order to increase the power production of a particular WEC, usually the WECs are tuned with the wave climate at the target location. However, in order to achieve the maximum profitability, the WECs must be able to be deployed in a bunch of locations with different wave climates. Therefore WECs must be flexible to be adapted to different kind of locations.
The matchability of a device could be achieved via the PTO control or changing the geometric characteristics of a particular device. In this study, an analysis about how the geometric tuning of a generic wave energy converter affects to different climate scenarios is performed.
Firstly, a generic wave energy converter is assumed to be formed by an array of floating cylinders that absorb in heave. Three options are proposed in the present study, a cylinder with its natural period on 4 s, typical of enclosed seas, another option with a natural period of 8 s (mean Atlantic swell) and an option that is tunable as a function of the location in order to evaluate the influence of tuning on the power performance.
The power matrix is computed with a frequency domain model and then, the converters are evaluated worldwide, taking the met-ocean data from a global reanalysis database (GOW) from Reguero et al (2012). The results are presented in terms of two main indicators, on one hand, the capture width ratio, that evaluates the efficiency of the converter on each location, and the kW/Ton parameter that evaluates the efficiency of the converter on “economic” terms.
Finally, tuning a converter for each location of deployment resulted positive in terms of capture width ratio, however regarding the kW/Ton indicator tuning resulted useless due to the heaviness of the structures needed to tune the converter with high peak periods. The number of suitable locations (in terms of an acceptable kW/Ton indicator) was higher as the mass of the structure is reduced, regardless of the natural period of the converter, thanks to a good performance of high natural periods converters.