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:
Bettergy will develop a catalytic membrane reactor to allow on-site hydrogen generation from ammonia. Ammonia is much easier to store and transport than hydrogen, but on-site hydrogen generation will not be viable until a number of technical challenges have been met. The team is proposing to develop a system that overcomes the issues caused by the high cracking temperature and the use of expensive catalysts. Bettergy proposes a low temperature, ammonia-cracking membrane reactor system comprised of a non-precious metal ammonia cracking catalyst and a robust composite membrane. A one-step cracking process will be used to convert ammonia into hydrogen and nitrogen, with the hydrogen passing through the selective membrane leaving only nitrogen as the byproduct. If the team is successful, the conversion efficiency will be higher than conventional methods because the hydrogen is removed from the system as it is being produced. The low-temperature reactor will provide greater reliability, ease of operation, and cost effectiveness to hydrogen fueling stations. The team’s technology could also be applicable for stationary fuel cell systems and the semiconductor, metallurgy, chemical, aerospace, and telecommunications industries.
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.