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:
Chemtronergy will develop an advanced solid oxide fuel cell (SOFC) system to electrochemically convert ammonia into electricity. Conventional SOFC systems are manufactured using ceramic fabrication techniques that are time-consuming, energy-intensive, and have high material costs. SOFCs also typically operate at 700-900°C to chemically activate the fuel feedstock and ensure that it is sufficiently cracked or reformed for electrochemical use. This high temperature, however, imposes harsh operating conditions and stresses on the materials, which further increases costs. To address these challenges, the team proposes to lower the operating temperature below 650°C and to develop anode, cathode, and electrolyte materials using a combination of advanced materials discovery, reaction kinetics modeling, and 3D printing technology for large-scale rapid prototyping. The team hopes to greatly reduce the cost of SOFC systems while providing a distributed power-generating option with high efficiency, long life, and a reduced carbon footprint.
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.