Solid oxide fuel cell (SOFC) technology being developed by the U.S. Department of Energy (DOE) for coal-based central power generation is being adapted by the U.S. Office of Naval Research for use in advanced unmanned undersea vehicles (UUVs).
The Navy believes SOFC technology could be a transformative technology that could help to better meet ever-broadening mission profiles, enhance national security and maintain maritime superiority into the future. Its use in this regard is a demonstration of the considerable research and development (R&D) progress made by DOE’s Fuel Cell technology program since its inception in 2000.
The program, managed by the Office of Fossil Energy’s (FE) National Energy Technology Laboratory (NETL), is aimed at the development of clean, efficient and reliable fuel cell technology for central power generation. The goal is to take advantage of the technology’s high electrical efficiency, low pollutant emissions, and ease of carbon dioxide capture. Considerable progress has been achieved in performance, reliability, and cost.
Building upon FE’s SOFC innovation, the Office of Naval Research is taking advantage of additional features of the technology, such as modularity and fuel flexibility, to meet the U.S. Navy’s mission requirements.
A significant challenge in UUV development is the source of propulsion power, which must conform to strict size limits and be able to meet projected endurance requirements, ranging from days to weeks. Additional considerations include reliability; air-independent operation; refuelability; rapid start-up, shut-down, and load following; and the ability to operate with little to no “observables,” such as noise or hull discharges.
To address these challenges, the Office of Naval Research has selected several SOFC projects—some with roots in the FE Fuel Cell R&D Program—that have the potential to exceed the limits of current and future high-energy-density batteries.
In 2012, NexTech Materials Ltd., in partnership with Northrop Grumman, Precision Combustion, and Alliant Techsystems, received a contract from the Office of Naval Research to develop an SOFC-based system under the Long Endurance Undersea Vehicle Propulsion program. FE has supported NexTech’s development of SOFC technology for large-system applications through projects on seals, interconnect coating applications, novel cell design, and manufacturing analysis. In addition, Precision Combustion was previously supported by FE in the development of logistics fuel processors for SOFC power generation systems.
Also in 2012, FuelCell Energy received an Office of Naval Research contract under the Large Displacement Unmanned Underwater Vehicle Innovative Naval Prototype program. FuelCell Energy is one of three Solid State Energy Conversion Alliance (SECA) Industry Teams within FE’s Fuel Cell R&D Program, and is utilizing SOFC technology developed by its subsidiary, Versa Power Systems Inc. In the U.S. Navy project, FuelCell Energy is partnered with NASA, Yardney Technical Products, the Naval Undersea Warfare Center (NUWC), and Pacific Northwest National Laboratory (PNNL). FE has funded SOFC research by both PNNL and NUWC; PNNL is the lead national laboratory developing core SOFC technologies under the SECA program, and NUWC previously received funding to evaluate SOFCs, including those manufactured by Versa and Delphi, under extreme conditions.
Although the naval projects are not directly related to central power generation, their success is expected to provide the electric power industry with valuable SOFC operational experience and contribute to the manufacturing base required for future low-cost mass production.