Abstract
Ocean wave energy is a rapidly emerging renewable energy resource, primarily due to the higher power density and steadier power input compared to solar and wind. The development of ocean wave energy conversion technology is critical to support the growth of the blue economy and supporting the goal of net-zero emission by 2050. However, there are many challenges that need to be addressed to understand the geospatial performance dependencies between Wave Energy Converter (WECs) archetypes and gross wave resources.
One important challenge is the lack of generic WEC archetypes (unlike solar and wind energy). Therefore, it is difficult to have tractable methodologies to provide accurate assessments of the power production potential of WECs, and the suitable devices to be deployed at the best ocean sites. Accordingly, this paper proposes a novel Wave Net Power Assessment (WNPA) method which is generally applicable to WECs regardless of dimensions, shapes, and degrees of freedom. This new technique is applied to conduct a geospatial analysis of wave power production potential along U.S. coastlines and provide WEC developers with meaningful data to make decisions about the best spatial region to deploy certain sized WECs.
Unlike the conventional wave resources assessment method (which quantifies wave gross power based on wave characteristics), the proposed WNPA method (utilizing a device point-of-view) is derived based on two theoretical power limits: the radiation limit and the Budal’s limit. This could be considered as a partial step towards the Technical Resource, as per Kilcher et al. 2021. The radiation limit assumes the WEC is always resonant with ocean waves but doesn’t consider the actual dimensions of the device. In contrast, Budal’s limit considers the actual size of the WEC and assumes the WEC can completely utilize the swept volume of the device. These two power limits are implemented to have a more accurate theoretical limit assessment of the net power available for WECs. When utilized to filter conventional wave resource data, the net power is can be calculated across U.S. coastlines and exclusive economic zones (EEZ) to generate high-resolution geospatial maps.
In this research, numerical simulations will be conducted for WECs with different sizes (characteristic dimensions of 2, 10, and 25), and degrees of freedom (surge, heave, and pitch) by using the wave data downloaded from Marine Energy Atlas (from 2001 to 2010) for Hawaii, West Coast, and East Coast. Based on the generated maps, the analysis will be conducted from a continental-scale point of view, to assess the spatial and temporal variability of the net power and the maximum efficiency of different WECs, as well as a local point of view (ocean sites of interest - including PacWave (Oregon), Wave Energy Test Site (WETS, Hawaii), and Jennette's Pier (North Carolina))