A Vision for Renewable Energy Powered Hydrogen Production on the Seafloor 

By Eric Hahn, Faculty Associate-Research, Energy Academic Group

Mr. Ben Wilcox, a Naval Facilities Engineering and Expeditionary Warfare Center engineer, has a vision for an open-source virtual environment for education and planning for a maritime hydrogen fueling station powered by an ocean thermal energy conversion (OTEC) plant ship.     

Ben’s existing virtual model depicts an envisioned OTEC system of six 100 megawatt plants that power hydrogen electrolysis on the seafloor at 3400m. The plants are integrated into a Mobile Offshore Base floating platform concept set up as a “plant ship” for hydrogen refueling. An OTEC cold water pipe (CWP) extends 1000m below it.   

OTEC power is available in equatorial ocean regions between 20° north and 20° south latitudes. 3400m is the average depth in these locales. Given the ambient pressure at this depth, hydrogen can be produced at 350 bar or 5000 psi, which is a standard pressure for larger hydrogen gas cylinders (as for example in fuel cell buses).     

An opportunity for innovation exists to pair renewable power with seafloor hydrogen production. This production concept avoids significant hydrogen compression and storage requirements. Exploring the opportunity in a virtual environment supports study directed towards maritime hydrogen fuel production for future ships that have an integrated power system and electrical architecture that can be adapted to fuel cells.     

Future Navy ships, adapted to operate on hydrogen that can be produced in ocean locales closer to the tactical edge, will reduce dependence on petroleum fuel lines of communication.