Through expeditionary advanced base operations (EABO) and distributed maritime operations, the Navy–Marine Corps team wants to complicate an adversary’s ability to locate and target friendly forces. But geographic distribution strains logistics, and each resupply potentially gives away a friendly location, thereby undermining the purpose.
A recent Center for Strategic and International Studies panel suggested that EABO is not viable because of these logistic risks.1 The Marine Corps has reintroduced foraging into its training to mitigate some of the burden, and water can be sourced locally and purified. But fuel is a substantial and bulky requirement for modern, power-hungry operations by crewed, uncrewed, and optionally crewed vessels. Even so, it is possible to imagine a battlefield where food, water, and fuel are foraged.
The way the Navy moves refined liquid fuels might work in a distributed environment, but it would require numerous, stealthy delivery platforms. Lithium-ion batteries are common, but even technologically mature versions degrade in harsh environments. Plus, batteries are heavy for the energy provided; do not get lighter as their energy is expended; require rare metals and frequent charging; and do not lessen the need to transport bulk material. The Marine Corps hydrogen tactical refueling point (H-TARP) could be a solution, but it requires aluminum that must be transported around the battlespace.2 Even if batteries or aluminum could be prestaged, those stores would need to be protected.
Nevertheless, hydrogen is a particularly enticing and versatile fuel. It has a high gravimetric energy density—providing more energy from less mass compared to other fuels.3 Hydrogen is also the most abundant element on Earth and can be refined almost anywhere through hydrocarbon reforming or electrolysis. It can be stored as a compressed gas or a liquid, with liquid hydrogen having greater volumetric energy density. Hydrogen can be combusted in a heat engine, such as a gas turbine, or oxidized in a fuel cell.
The Navy actually investigated hydrogen fuel after the 1973 oil embargo. But while the Naval Research Laboratory (NRL) found it nominally feasible, technological maturity, low volumetric energy density, a lack of infrastructure, and safety concerns formed significant barriers to adoption.4
The NRL report was correct for its time, but these barriers largely no longer apply. First, the report presumes that fuel must be transported across the battlespace. If the fuel is being made in situ to meet demand, then volumetric energy density for transport is irrelevant, and gravimetric density becomes more relevant. If the fuel is being made by a nuclear reactor on a ship or renewables on shore, then infrastructure is of limited concern.
Hydrogen is not without risk. But despite popular notions of the Hindenburg disaster, hydrogen is more flammable than explosive, as is also true for many refined petroleum products. Hydrogen flames are invisible, and the gas is odorless, tasteless, and colorless, which raises concerns for shipboard use.5 They can be mitigated, however. The Navy is procuring hydrogen sensors for normal operations and firefighting. And it is revising the current Naval Ships’ Technical Manual 550 on the generation, storage, and handling of industrial gases, including hydrogen. The Department of Energy also has conducted hydrogen ground vehicle tests that illustrate hydrogen’s relative safety as a modern fuel.6
Harvested fuel has numerous military advantages. Strategically, it reduces reliance on fuel imports and reduces the risks of supply chain disruptions. Harvesting hydrogen reduces the operational burden of transporting fuel and, tactically, reduces the visible logistics tail of friendly units. Hydrogen fuel cells are acoustically silent and have a low thermal signature. They also improves vehicle endurance, up to ten times greater than that of similar vehicles using batteries.7 Thus, harvested hydrogen coupled with foraging—the byproduct of fuel-cell oxidation is potable water—holds the promise of making EABO tenable. In addition, hydrogen is more environmentally friendly; if combusted, it produces fewer greenhouse gases than petroleum.8
Burn, Baby, Burn
Hydrogen is already in use as a fuel in air, ground, surface, and subsurface vehicles. Airbus is developing three variations of hydrogen-fueled commercial aircraft, with the goal of flight testing in 2025. The aircraft burn liquid hydrogen in their turbofan engines for propulsion and employ hydrogen fuel cells for electrical power. This hybrid-electric system (HES) will increase flight endurance for large passenger aircraft—with zero carbon emissions.9 The joint Marine Corps–Air Force “Agility Prime” initiative seeks to develop an HES vertical take-off and landing aircraft for logistics.10
On the ground, the Chevy Colorado ZH2 uses fuel cells and has been tested as a potential replacement for the Joint Light Tactical Vehicle.11 The Office of Naval Research is developing the Refueling and Support Package to Enable Communications and Situational Awareness (RASP-CASA) to generate hydrogen and oxygen in a shipping container. The system will use renewable sources to generate, store, and deliver hydrogen for use by unmanned vehicles.
A variety of civilian ferries, research vessels, and cargo ships use hydrogen. SWITCH Maritime’s zero-emission ferry began operation in San Francisco Bay this year. It carries 75 passengers and is powered by hydrogen fuel cells.12 The Energy Observer 2 was unveiled in France this year, employing hydrogen and advanced fuel cells to transport up to 240 freight containers.13 And almost a decade ago, researchers demonstrate that Navy gas turbines can be modified to burn hydrogen.14 Many submarines use air-independent propulsion systems that pair diesel engines with hydrogen fuel cells.
Suffice it to say, using hydrogen as fuel is possible, and hydrogen can be harvested. The Navy has even patented technology to harvest hydrogen from seawater, and harvesting from ambient air also is possible.15 However, harvesting systems will need to be designed and built to scale.
Consider Marines at an expeditionary advanced base. The equipment to produce, store, and use hydrogen fuel ashore is embarked on the ship in a Conex box. The equipment is offloaded during a traditional ship-to-shore movement. Marines who have been trained to handle hydrogen safely deploy and operate an electrolytic-cation exchange module, based on one developed by the NRL. Using renewable sources of power such as solar or wind generators, this device produces hydrogen and carbon dioxide from ambient air or seawater. This allows the Navy to reduce the logistics tail on fuel delivery to remote locations as well as increase energy security and independence. The hydrogen is used to fuel unmanned vehicles and other equipment. Once a microgrid is set up, the system of systems stores excess energy for use during intermittent generation. Potable water is a useful byproduct.
Taken in aggregate, the combination of foraging for food and hydrogen harvesting is a recipe for answering General Jim Mattis’s call from the Iraq War: “Free me from the tether of logistics.” This could be the bridging technology that makes distributed naval concepts a practical reality.
1. Todd South, “Lethal and Survivable or Irrelevant and Vulnerable? Marine Redesign Debate Rages,” Marine Corps Times, 16 May 2022.
2. Scott Hochenberg, “Making Hydrogen Fuel Anywhere: ONR Tests Prototype to Power Marines in Expeditionary Environments,” navy.mil, 15 February 2022.
3. Department of Energy, “Hydrogen Storage,” www.energy.gov/eere/fuelcells/hydrogen-storage.
4. H. W. Carhart, W. A. Affens, B. D. Boss, R. N. Hazlett, and S. Schuldiner, Hydrogen as a Navy Fuel (Washington DC: Naval Research Laboratory, 12 June 1974).
5. Yousef S. H. Najjar, “Hydrogen Safety: The Road toward Green Technology,” International Journal of Hydrogen Energy 38, no. 25 (August 2013): 10716–28.
6. Michael R. Swain, “Fuel Leak Simulation,” energy.gov, 5 March 2001, 11.
7. N. Lapeña-Rey et al., “A Fuel Cell Powered Unmanned Aerial Vehicle for Low Altitude Surveillance Missions,” International Journal of Hydrogen Energy 42, no. 10 (March 2017): 6926–40.
8. Pavlos Nikolaidis and Andreas Poullikkas, “A Comparative Overview of Hydrogen Production Processes,” Renewable and Sustainable Energy Reviews 67, no. 1 (January 2017): 597–611.
9. “ZEROe—Zero Emission Airbus,” airbus.com, 24 June 2021.
10. Elan Head, “U.S. Marine Corps Partners with Air Force to Explore eVTOL Potential,” Vertical Mag (blog), 12 March 2022.
11. Kevin Centeck, “U.S. Army Combat Capabilities Development Command Hydrogen Fuel Cell Technology and Its Military Applications,” hydrogen.energy.gov, 19.
12. “AAM + SWITCH Maritime Announce the Launch of Sea Change,” All American Marine (blog).
13. Katia Nicolet, “Energy Observer 2, a Demonstrator Vessel That Runs on Liquid Hydrogen,” Energy Observer, February 2022.
14. M. Morsy El Gohary and Ibrahim Sadek Seddiek, “Utilization of Alternative Marine Fuels for Gas Turbine Power Plant Onboard Ships,” International Journal of Naval Architecture and Ocean Engineering 5, no. 1 (March 2013): 21–32.
15. Heather D. Willauer et al., “Development of an Electrolytic Cation Exchange Module for the Simultaneous Extraction of Carbon Dioxide and Hydrogen Gas from Natural Seawater,” Energy & Fuels 31, no. 2 (February 2017): 1723–30.