Abstract
The coastal oceans off the US hold substantial amounts of resources with significant socioeconomic benefits. The US marine energy resource can provide a little over half of the US energy generation and on smaller scales, marine energy devices have relevance for Powering the Blue Economy (PBE) applications such as supporting offshore power needs for ocean observations, monitoring equipment for offshore wind operations, and power requirements of nautical navigational aids. Additionally, wave energy converters (WECs) are being developed for desalinating seawater during emergency natural disasters for coastal communities. In these PBE applications, WECs are challenged by twisting and axial loading of the primary mooring line which can damage cables and decrease the device’s performance or render the device inoperable. To advance marine energy, this challenge must be addressed to support WECs as a more viable marine energy option. Current solutions include deploying a secondary anchor, but this has limitations (e.g., increased entanglement risk, potential dampening of available energy for the WEC’s power takeoff system, increased deployment costs, and fatigue and or failure of the WEC should the secondary anchor fail). We are developing a slip ring-swivel mooring system (i.e., a slip ring and swivel joint that are concentrically oriented and integrated with a spring-damper system) to handle rotation and axial loading while maintaining electricity and fluid (e.g., desalinated water) transmissions.
Design and development of the slip ring-swivel mooring system are guided by specific requirements (e.g., functional, performance, user, policy and regulatory, and interface requirements, design constraints, etc.) that characterize the environmental conditions while the design approach includes conceptual and preliminary designs, design options and selection, and design validation. To assess the impact that this marine energy technology will have on marine energy devices, we will perform a preliminary feasibility assessment to evaluate the range of magnitude costs, the economic considerations, and the applications to marine energy devices. This evaluation will examine factors (e.g., capital expenses, operating expenses, personnel and fringe, etc.) to understand the costs associated with the slip ring-swivel mooring system and how the mooring system will support the economic viability of marine energy devices. It is expected that the slip ring-swivel mooring system will increase the period of performance by extending operational times of marine energy devices and thus impact their economic evaluation (e.g., life cycle cost). By accounting for the economic considerations, we will assess the slip ring-swivel system’s expense and determine the value that the slip ring-swivel system brings to marine energy devices. The slip ring-swivel mooring system aims to make marine energy devices more competitive and economically viable which will help advance the marine energy industry; thus, supporting America’s energy independence and energy resiliency.