SBIR-STTR Award

Ocean Power Technologies (OPT) has identified a large market for offshore marine renewable systems that can provide power to seafloor equipment (e.g., Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV) battery recharging, gas and oil well monitoring, ocean observing). Existing wave energy converter (WEC) systems have various shortcomings that present barriers to entry for many offshore power markets. One of these barriers is cost – both of the WEC and mooring equipment, as well as installation and removal. This cost is driven by the size and complexity of the WEC and mooring systems. Another barrier is scalability, as different applications present a wide range of power demands. OPT has developed a concept for a Mass‐on‐Spring Wave Energy Converter (MOSWEC) which overcomes the shortcomings of existing WECs. The innovative MOSWEC device can be modularized and scaled up or down in size to support a broad range of power needs. The MOSWEC “power module” can be incorporated into a stand‐alone PowerBuoy® by adding a flotation collar around the top, coupled to other MOSWEC power modules to form a larger PowerBuoy®, or could be installed into existing end user buoys or vessels. The patented, inertia‐based MOSWEC buoy utilizes a mass‐spring oscillator (MSO) housed in an airtight compartment near the bottom of the buoy. All moving parts, including the MSO and power take‐off (PTO), are isolated from external elements. Wave motion applies up and down (heave) forces to the buoy hull. These forces are transferred to the buoy’s internal “reaction mass” and PTO via a tuned spring, which reacts out‐of‐phase with the hull due to the inertia and spring coupling of the reaction mass. The resulting differential motion and force between hull and reaction mass produces mechanical power that is converted to electrical power by the PTO. Unlike many competitor WEC technologies, the MOSWEC does not need to have a deep draft to be efficient at wave energy capture. A buoy using the MOSWEC approach can be much shorter than many other WEC buoys, resulting in lower structural loads, simpler moorings and umbilicals, and simpler launch and recovery operations. OPT proposes to develop (in Phase I) and demonstrate (in Phase II) a new WEC system comprised of its MOSWEC technology. The Phase I study involves consultation with Hibbard Inshore, an AUV end user and services provider, to determine power requirements for the MOSWEC and a Phase II demonstration. The Phase I project includes preliminary design of short spar‐shaped power module with a 2 to 3 kW peak average power capability. In addition, OPT will show through conceptual design and analysis that the basic building block spar MOSWEC can be scaled up in size and configured in coupled groups to provide over 50kW peak average power in an incremental, cost‐effective fashion, or alternatively scaled down in size to serve as a wave energy harvesting module for end user buoys and surface vessels. The proposed work is critical to the commercialization efforts that are being undertaken by OPT and other renewable marine energy developers. DOE’s role in the development of a modular and scalable WEC is essential to enable efforts such identified in this proposal to be undertaken in a timely manner and carried out to completion. The award of this project would allow the immediate start of the proposed tasks which would otherwise be a major burden on a small business such as OPT. Collaboration with ROV/AUV end‐user Hibbard Inshore will accelerate development and supplement OPT’s own expertise. The DOE funding will leverage conceptual work that has already been performed at OPT. Thus, DOE funding will advance the development of an innovative approach to support resident ROV/AUV operations and a wide range of other remote offshore power applications. It will also support the USA’s continued leadership in the deve

Ocean Power Technologies (OPT) has identified a large market for offshore marine renewable systems that can provide power to topside sensors and/or seafloor equipment for various ocean observing and subsea power applications. Existing wave energy converter (WEC) systems have various shortcomings that present barriers to entry for many offshore power markets, such as cost, reliability, and scalability to support the wide range of power demands across different applications. OPT has developed a concept for a Mass-on-Spring Wave Energy Converter (MOSWEC) which overcomes the shortcomings of existing WECs. The MOSWEC “power module” utilizes a mass-spring oscillator (MSO) housed in an airtight compartment near the bottom of the buoy which can be incorporated into a stand-alone PowerBuoy® by adding a flotation collar around the top, coupled to other MOSWEC power modules to form a larger PowerBuoy®, or scaled up for larger power. All moving parts are isolated from external elements. A buoy using the MOSWEC approach can be much shorter than many other WEC buoys, resulting in lower structural loads, simpler moorings and umbilicals, and simpler launch and recovery operations. The design is inherently modular and scalable, allowing it to address varying power demands across different applications. In the Phase I study, OPT completed conceptual design of the MOSWEC system and analyzed various design configurations to verify estimated power levels of different modular and scaled approaches. A base building block with a 3-tonne reaction mass was developed that is estimated to achieve an average peak power of 2 kW, with different configurations providing power levels up to nearly 30 kW. In addition, two main applications were evaluated for technical and commercial feasibility – integration of a subsea AUV docking station and a topside sensor payload for maritime domain awareness. While both applications were confirmed to be technically feasible, the topside monitoring payload for maritime domain awareness was found to have more near term commercial viability. Development of the MOSWEC technology is anticipated to accelerate market adoption of WECs in several applications, reducing the need for crewed vessel patrols and displacing carbon-emitting sources for subsea power applications. For Phase II, OPT proposes to complete detail design, build, and ocean testing of the initial prototype with a 3-tonne reaction mass, referred to as the “M3” MOSWEC. The M3 prototype will be deployed with a topside payload consisting of radar, camera, and AIS to serve as an offshore vessel monitoring system that has applications in defense and security, monitoring of illegal fishing and marine protected areas, enforcement of safety exclusion zones for offshore construction, and tracking vessels traffic in ports or shipp