Abstract
The WATTERJacks team at Northern Arizona University developed a new wave-powered energy system for the 2025 Marine Energy Collegiate Competition (MECC). Their interdisciplinary, student-led project addresses an urgent and daunting challenge in naval defense, environmental monitoring, and oceanographic exploration: how to supply stable and sustainable electrical power to underwater systems within remote, high-pressure, and inaccessibly situated marine environments. Their device is a semiautonomous, modular energy harvesting system that transforms the vertical motion of waves into electricity. Their system is designed for long-term, off-grid subsea deployment and minimizes reliance on conventional power sources such as diesel generators, throwaway batteries, and undersea cabling.
The system's focal point is a yo-yo-shaped surface buoy that converts the kinetic energy of wave-stimulated vertical motion into one-way rotation. This mechanical movement powers a geared generator to provide electricity to power storage in lithium-ion battery modules housed within pressure-resistant enclosures. The unit is configured for modularity for adaptable power setups on a scalable basis, based on mission duration and power requirements. The product is purpose-built for ocean use, with corrosionresistant elements, sealed electronics, and thermal management systems designed to preserve operating efficiency in variable ocean conditions. Focus was also given to stealth and low-profile operations to facilitate covert missions, particularly in defense-oriented situations where device detectability needs to be minimized.
The WATTERJacks identified four principal marketplace applications for their system: 1) powering underwater communication nodes for military and surveillance missions; 2) powering autonomous underwater vehicles (AUVs) and sensor networks; 3) powering oceanographic monitoring for climate and ecological research; and 4) powering persistent, remote environmental sensing platforms. Industry and government stakeholders, such as Kenautics, the Naval Research Laboratory, and the Salt River Project, in interviews and technical discussions, validated these use cases and helped shape some of the primary design features. Stakeholder input emphasized reliability, modularity, field serviceability, and surface-tether-free and power-supply-cable-free aspects as essential design features.
Economic modeling demonstrated that the system would be a cost-saving option compared to conventional power delivery methods. A complete deployment is projected to achieve break-even in around five years, driven by reductions in logistical support needs, fuel transport costs, and maintenance cycles. The system is beautiful for long-duration deployments when periodic servicing is not possible. Technical validation of the concept included simulation modeling with real NOAA buoy wave data, subsystem testing on bench-top generator configurations, and system-level tests in university laboratory environments. While full open-ocean tests were not within the competition timeline, scaled-test results closely mirrored expected performance criteria, reinforcing confidence that the design scales and is robust.
The team's prototype was able to capture wave motion energy, store it in modular batteries, and operate reliably in simulated marine environments. The device had significant functional specifications, including one-way gear engagement, high-energy storage efficiency, and watertight electronics integration. Subsystem integration proved low power losses and high consistencies on multiple test runs. The consistency facilitates future system efficiency improvements, especially in the gearbox and power electronics.
In the future, the WATTERJacks team will continue to optimize the mechanical efficiency of the geartrain, improve the energy management and battery balancing systems, and upsize the physical structure of the buoy for greater energy capture. Controlled open-water testing will give further insight into the device's performance in real-world conditions, specifically its hydrodynamic performance and energy generation under different sea states. Further cooperation with marine engineers and naval researchers will assist in preparing the system for certification and operational deployment.
Overall, the NAU WATTERJacks team successfully designed and tested an innovative wave energy system tailored for isolated underwater use. Their work supports the strategic goals of increasing marine renewable energy use, improving the sustainability of ocean facilities, and improving national defense, autonomous systems, and climate research capabilities. The project shows the ability of student teams to contribute significantly to real engineering challenges and lay the groundwork for future innovation in the marine energy sector.