Abstract
The amount of energy we use and the ways that we get that energy sit on the edge of dramatic change as the carbon budget which can keep the planet under 1.5C of global average temperature increase gets smaller (Allen, 2018). In response, we continue to research and develop renewable energy technologies. Among these technologies are a diverse set of devices intended to convert the mechanical energy of wind-driven ocean waves to usable energy, typically in the form of electricity. Currently, researchers and developers work on wave energy devices for grid-scale energy applications as well as other emerging markets, such as ocean observation or desalination. Despite the large scope of potential uses for the technology, it is not currently being used as an energy source for any market. For many applications, the price remains too high and the technology too new.
The unique challenges for wave energy converter design---integrating complex and uncertain technological, economic, and ecological systems, overcoming the structural challenges of ocean deployment, and dealing with complex system dynamics---have led to a disjointed progression of research and development. There is no common design practice across the wave energy industry and there is no published synthesis of the practices that are used by developers. This lack of established process likely contributes to the slow forward motion of the wave energy industry.
In this body of work, I have integrated knowledge of engineering design processes with research in current wave energy converter (WEC) design challenges and pathways, in order to better understand and improve WEC design practice. The results from these studies reveal the dominance of point-based design approaches in the field of WEC design, the areas of WEC design in which methodological improvements are most necessary, and the need for significantly better ways of distinguishing between the performance potential of WEC concepts. Despite the significant attention given to late-stage design optimization by academic researchers, developers are in need of improved tools for earlier in the process. Point-based design, even with late-stage optimization is not sufficient or entirely appropriate for the field of wave energy. Set-Based Design, multi-attribute utility analysis, the improvement of holistic performance assessments, and the conversion of those assessments for use in the conceptual design stage are the four methods which I examine in this work to improve early-stage WEC design.
Chapter of this thesis were peer reviewed and published in the Journal of Marine Science and Engineering and Chapter 3 peer reviewed and published at the European Wave and Tidal Energy Conference in 2019. Chapters 4 and 5 were submitted to the U.S. Department of Energy.