Methane Harvesting for Seafloor Generation

Autonomous underwater vehicles (AUVs) are critical to DoD undersea missions including the future capabilities for sea and sub-sea forces communication and connectivity. AUV mission lengths are currently limited to 24 hours due to the prohibitive battery storage and AUV energy demands. Makai Ocean Engineering, with the University of Hawaii’s Hawaii Natural Energy Institute (HNEI), proposes to develop an AUV subsea recharging technologies that collects gaseous methane from seafloor seeps and converts it into usable energy. The methane conversion system proposed for this effort will capture and reform methane to produce electricity at a fuel cell and will recharge AUVs from a single seafloor station. The methane will be reformed to H2 using previously demonstrated H2O2 reforming processes, and the H2 converted to electricity at PEM or AFC fuel cells. The project team will leverage HNEI’s extensive past research in seafloor methane and fuel cell systems, and Makai’s experience developing subsea technologies for DoD applications including seafloor AUV/UUV docking stations. The technical objective for the Phase I effort is to prove the system’s feasibility, optimize for SWaP (Size Weight and Power), system lifetime, and to develop preliminary prototype designs for seafloor energy production suitable for a Phase II at-sea demonstration.