Sandia is creating on an open-source catalogue for wave-energy converter (WEC) developers with a detailed and consistent wave resource characterization at three US test sites

  • the Wave Energy Test Site (WETS) in Kaneohe Bay, HI;
  • the North Energy Test Site (NETS) offshore of Newport, OR; and
  • a potential site offshore of Humboldt Bay, CA.

Hindcast simulation data will be used at each site to calculate resource characteristics, as suggested by the draft International Electrotechnical Commission (IEC) Technical Specification (TS) on Wave Energy Characterization. Researchers at the Hawaii National Renewable Energy Center (HINREC) and the Northwest National Marine Renewable Energy Center (NNMREC) have completed wave hindcast simulations at WETS and NETS, respectively. Sandia is working on a 10-year hindcast simulation for the Humboldt Bay area and investigating spatial variability of the wave resource.

Wave-energy resources have been analyzed and presented in various ways throughout the literature. For example, efforts have included analyses of measured buoy data and/or hindcast simulation data; some consider full directional spectra, while some only consider bulk parameters; extreme event analyses are often neglected or considered in separate studies. This ambiguity and difficulty in comparing assessments are some of the reasons that the IEC began the process of creating a TS. 

[1]  Sandia will generally follow the TS’s guidelines for this Humboldt Bay effort by analyzing directional wave spectra produced from a simulated hindcast.

Average monthly values of the six parameters specified by the IEC TS on Wave Energy Characterization near Humboldt Bay, California. Data is taken from NDBC46212 from 2004–2012 as an example. The error bars signify one standard deviation.

Average monthly values of the six parameters specified by the IEC TS on Wave Energy Characterization near Humboldt Bay, California. Data is taken from NDBC46212 from 2004–2012 as an example. The error bars signify one standard deviation.

The six parameters suggested by Lenee-Bluhm et al. [2] and specified in the TS for characterizing a sea state are

  1. omnidirectional wave power,
  2. significant wave height,
  3. energy period,
  4. spectral width,
  5. direction of maximum directionally resolved wave power, and
  6. directionality coefficient.

Definitions can be found in [Reference 2]. Joint probability distributions and estimates of weather windows and extreme events will also be provided. An example of the parameters specified above are shown in the figure, which is analyzed from buoy data (NDBC46212) in 40 m depth. Further information can be found in the Marine Energy Technology Symposium 2014 paper that was presented on this work. [3] [1] Folley, M., Cornett, A., Holmes, B., Lenee-Bluhm, P., Liria, P., “Standardising resource assessment for wave energy converters,” Proceedings of the 4th Annual International Conference on Ocean Energy, Dublin, Ireland, 2012.

[2] Lenee-Bluhm, P., Paasch, R., Özkan-Haller, H.T., 2011, “Characterizing the wave energy resource of the US Pacific Northwest,” Renewable Energy, 36(8), 2106–2119 (August 2011).

[3] Dallman, A., Neary, V., “Initial Characterization of the Wave Resource at Several High Energy U.S. Test Sites,” Proceedings of the 2nd Marine Energy Technology Symposium, Seattle, WA, April 15–18, 2014.