Abstract
Comprehensive and consistent analysis, characterization, classification and cataloguing of the wave climate at open-ocean wave energy converter (WEC) test sites guided by international standards enables evaluation and comparison of the wave energy resource and load conditions with other WEC test sites. Standard resource metrics and plots can inform test planning and test device design. Herein, we present results from a comprehensive feasibility-level wave resource characterization for several Atlantic Marine Energy Center (AMEC) WEC test sites in the Gulf of Maine. Summary metrics and plots characterizing wave resource and wave load conditions are computed from data generated using a validated high-resolution 42-year spectral wave model hindcast. Best practices recommended by several International Electrotechnical Commission (IEC) technical specifications are employed, including those in the wave energy resource assessment and characterization technical specification (IEC TS 62600-101) that details suitable numerical models, recommended model validation and data analysis procedures for computing and plotting six key parameters for characterizing the wave energy resource, and those in the design technical specification (IEC TS 62600-2) that requires estimation of n-year extreme wave heights, environmental contours and sea states to characterize wave load conditions. The wave energy resource class and the WEC or wave load type-class are also determined for comparison to other US WEC test sites that have been catalogued. Compared to other US WEC test sites, the AMEC test sites offer a less energetic wave climate for WEC testing compared to those in the Pacific, e.g., PacWave South and WETS. The mean omni-directional wave power at the most frequently occurring sea state at one AMEC open-ocean test site, 1.95 kW/m, occurs for a significant wave height between 0.5 and 1.0 meters and an energy period between 6 and 7 seconds, while the sea state contributing the largest percentage of the power occurs for a significant wave height between 1.0 and 1.5 meters and an energy period between 7 and 8 seconds. By comparison, at PacWave South, the mean omni-directional wave power for the most frequently occurring sea state is 13.26 kW/m, occurring for a sea state with significant wave height between 1.5 and 2.0 meters and an energy period between 8 and 9 seconds. Seasonal variability is most pronounced for the monthly mean omni-directional wave power and significant wave height. In the northern region of this site, the monthly mean omni-directional wave power and significant wave height are largest in March, reaching values of 8.24 kW/m and 1.13 meters, respectively, while the smallest values are found in July at 1.65 kW/m and 0.65 meters. The timing of the peak values is in contrast with sites in the Pacific Northwest, such as PacWave South, which typically reach peak monthly mean values in December. Similar to PacWave south, seasonal variations are less pronounced for the direction of maximum directionally resolved wave power. Our study demonstrates the value of employing standard best practices with consistent methodologies for comparing wave resource and conditions data. The AMEC WEC test sites offer a unique wave climate to demonstrate and test devices.