Most liquid fuels used in transportation today are derived from petroleum and burned in internal combustion engines. This combination is attractive because of the high energy density of the fuels and current economics, but it remains partially reliant on imported petroleum and is highly carbon intensive. Alternatives to internal combustion engines, such as fuel cells that convert chemical energy to electricity, have shown promise in vehicle powertrains, but are hindered by inefficiencies in fuel transport and storage. Carbon-neutral liquid fuels (CNLFs), such as ammonia, used in conjunction with fuel cells, offer an alternative transportation system that addresses these challenges. These fuels can be produced by converting water and air using chemical or electrochemical processes powered by renewable electricity. The resulting CNLFs can be stored and transported using existing liquid fuels infrastructure to the point-of-use. However, there are technical challenges associated with converting CNLFs to hydrogen for use in conventional fuel cells or directly to electricity. Advanced materials such as membranes and catalysts and new electrochemical processes are required to efficiently generate hydrogen or electricity from energy-dense CNLFs at higher conversion rates and lower costs.
Project Innovation + Advantages:
FuelCell Energy will develop an advanced solid oxide fuel cell system capable of generating ammonia from nitrogen and water, and renewable electricity. The unique design will also allow the system to operate in reverse, by converting ammonia and oxygen from air into electricity. A key innovation in this project is the integration of proton-conducting ceramic membranes with new electride catalyst supports to enable an increase in the rate of ammonia production. Combining their catalyst with a calcium-aluminate electride support increases the rate of ammonia formation by reducing coverage of the catalyst surface by hydrogen and allowing the nitrogen to use all of the catalyst area for reactions. The modular nature of this system allows for its deployment closer to the point of use at agricultural and industrial sites, working to both produce ammonia for immediate or delayed use and to use the ammonia to generate electricity after it has been transported to population centers.
If successful, developments from REFUEL projects will enable energy generated from domestic, renewable resources to increase fuel diversity in the transportation sector in a cost-effective and efficient way.
The U.S. transportation sector is heavily dependent on petroleum for its energy. Increasing the diversity of energy-dense liquid fuels would bolster energy security and help reduce energy imports.
Liquid fuels created using energy from renewable resources are carbon-neutral, helping reduce transportation sector emissions.
Fuel diversity reduces exposure to price volatility. By storing energy in hydrogen-rich liquid fuels instead of pure hydrogen in liquid or gaseous form, transportation costs can be greatly reduced, helping make CNLFs cost-competitive with traditional fuels.