SBIR-STTR Award

Ocean Power Technologies, Inc. (OPT) and its subcontractor ASSETT leverage their many years of experience with US Navy programs, energy harvesting buoys/vessels, and sonar systems to address the US Navys current and future needs for autonomous, anchorless, easy-to-deploy active sonar systems. OPT proposes an innovative inertia-based 0x9D wave energy harvesting buoy system that is capable of operating in various energy harvesting, vessel propulsion, and sonar system operating modes, to provide persistent operation of the ASW sonar system. The proposed inertia-based wave energy harvesting concept was first developed by OPT for other US Navy SBIR programs and is being enhanced to significantly improve the energy density (energy/volume) and specific energy (energy/mass) for this mission. OPT will work with ASSETT, Inc. of Manassas, VA to develop a smart energy sonar management adjunct to maximize mission endurance by adjusting the sonar duty cycle - pulse length and pulse repetition time as necessary for the given environment. ASSETT will also use its experience with parametric sonar systems to investigate alternate designs for shallow water environments that support direct path operation. The proposed multi-modal 0x9D sonar buoy system will use multiple energy harvesting, stationkeeping and sonar modes to provide a long-endurance mission capability.

Benefit:
Persistence is a key mission requirement for many DoD applications, and autonomous wave energy conversion PowerBuoys are a key enabling technology. Also, there are a number of military projects that aim to reduce dependency on expensive fossil fuels using hybrid systems. Wave energy technology has recently become a proven technology through many years of ocean testing and is currently available for defense and civilian applications such as maritime surveillance both for defense and homeland security including autonomous maritime vehicles, ocean observing, open ocean aquaculture, cellular communications, deep sea oil and gas exploration, and grid-connected utility power.

Keywords:
wave power, wave power, Solar Power, Sonar, Ocean wave energy harvesting, persistent at-sea operation, Alternative Energy

Ocean Power Technologies, Inc. (OPT) is proposing to continue the development of an anchorless, stationkeeping, buoy system which utilizes onboard wave energy conversion technology to supply renewable and persistent power to the propulsion and control system. This buoy system concept was developed during the SBIR I investigation as a persistent, deepsea platform for the USN DWADS active sonar array. The use of wave energy conversion and storage was proposed as a means for extending mission duration of the sensor array by utilizing renewable energy to support the energy demand of the stationkeeping propulsion and control system. The onboard diesel generator system could then be used solely for sensor powering. This project effort will utilize the initial design developed in Phase 1 to develop prototype buoy system suitable for field testing. The proposed project centers on the design of the wave energy conversion modules, buoy hull, and stationkeeping propulsion system. The final goal will be to produce a scale model system and to deploy and test the system in an offshore environment.

Benefit:
The OPT system has many benefits not offered by alternative approaches. Some of the benefits of the OPT system are: Excess wave energy can augment energy from diesel system. Direct wave-to-propulsion systems cannot do this. Stored energy can be used for propulsion during times of high current and/or low wave activity allowing for greater operational versatility and mission persistence. Direct wave-to-propulsion systems cannot do this. Options for long-term loitering, deployment from a distance, and semi-submergence for covert operation. Small surface expression. Potential for long-term operation due to robust encapsulated design. Negligible adverse effects from marine fouling (above and below water). Makes use of proven cost effective technologies with demonstrated scalability. Spin-offs for other US Navy, US Coast Guard, NOAA and other applications. The proposed system can be utilized for a number of missions such as environmental monitoring, long duration ASV, UUV recharging station and unmanned ocean mapping operations.

Keywords:
Sonar, persistent at-sea operation, Ocean wave energy harvesting, Alternative Energy, wave power, Solar Power