Abstract
As research interest in Blue Economy applications for wave energy continues to grow, developers are also increasingly engaging in non-utility scale market opportunities. While the wave energy converters (WECs) that will eventually be deployed in the Blue Economy emerging markets share some functional requirements with electricity grid WECs, there are new functional requirements for these Blue Economy markets.
In wave energy, there is a large focus on surface-piercing devices due to the high energy density at the ocean's surface. The change in functional requirements for these Blue Economy applications presents a unique design opportunity to examine fully submerged WECs. Fully submerged WECs are well-suited for certain Blue Economy applications such as ocean monitoring in high traffic areas. A fully submerged WEC has increased survivability due to being in a less energetic environment and at a depth that they are less likely to collide with ocean vessels. Being fully submerged also decreases area use conflicts with other ocean users. However, a submerged WEC may also suffer from the less energetic environment as it decreases the amount of electricity the WEC can generate. These tradeoffs make it unclear which WEC archetypes are best suited for subsurface deployment and there is little research to date that helps developers determine which subsurface archetype is best for their Blue Economy application. In this study, we investigate the wave energy resources at various depths and conduct a state-of-the-art review of fully submerged WECs to help us evaluate WEC archetypes. Investigating wave energy resources at various depths creates an understanding of the dominant degrees of freedom, which helps us determine the WEC archetypes that can successfully absorb power in a fully submerged deployment. This state-of-the-art review allows us to classify each device's archetype and provide an overview of each archetype’s functionality. We use the results of these investigations to conduct a Pugh Chart analysis of all fully submerged WEC archetypes, comparing against the FOSWEC and Carnegie Energy’s CETO 6. Through the Pugh Chart we gain an understanding of how WEC archetypes will perform in a fully submerged deployment. Better understanding of the wave resource and the design space of fully submerged WECs will help wave energy developers generate effective designs that will increase the appeal of concepts to Blue Economy stakeholders.