Fuel Cells for Transportation
The transportation sector is the single largest consumer of petroleum in the United States, accounting for nearly two-thirds of our annual consumption. Most of this, about 75%, is used to fuel highway vehicles, such as cars, trucks, and buses. In addition, highway vehicles are responsible for over 60% of the carbon monoxide emissions and about 20% of greenhouse gas emissions. A transportation system powered by hydrogen and fuel cells would significantly improve our national energy security and reduce emissions of harmful pollutants and greenhouse gases.
The Fuel Cell Technologies Office is working closely with the Vehicle Technologies Program to develop technologies that can advance state-of-the-art fuel cell systems for highway vehicles. DOE is concentrated on supporting research into core technologies to improve fuel cell systems and their subsystems and components. DOE's fuel cell systems research is focused on air, thermal, and water management technologies.
Air management. Most current automotive fuel cell systems are designed for pressurized operation to reduce system size, boost stack efficiency, and improve water management. The program is working with research partners to improve compressor and blower designs, develop hybrid compressor/expander modules, and reduce subsystem costs.
Thermal and water management technologies. The low operating temperature of PEM fuel cells limits the use of heat generated by the fuel cell. More efficient heat recovery systems and improved system designs are needed to use fuel cell waste heat and water to minimize the overall system size without compromising overall system efficiency.
In addition to fuel cell system research, DOE is sponsoring research to improve fuel cell subsystems and components and funding transportation "learning demonstrations" to prove fuel cell technologies in real-world applications.
Dual Pathway Development
DOE is pursuing PEM fuel cell systems fueled directly by hydrogen for fuel cell vehicles (FCVs). Prior to August 2004, significant resources supported on-board vehicle fuel processing, in which hydrogen is produced from fuels supplied by the existing infrastructure, such as gasoline, methanol, ethanol, natural gas, or other hydrocarbons. A review of on-board fuel processing activities was conducted. The review concluded that, based on the current state of the technology, on-board fuel processing was unlikely to improve sufficiently to support the transition to widespread commercialization of hydrogen and fuel cell technologies. Subsequently, DOE decided to discontinue on-board fuel processing R&D and focus on direct hydrogen fuel cell systems for transportation.
Auxiliary Power Units
The program is also supporting the development of auxiliary power units that run on reformate fuels for use on commercial trucks.
The status of DOE's transportation fuel cell R&D projects—fuel processing, transportation systems and balance of plant components, and fuel cell characterization—is detailed in the fuel cells section of the Annual Progress Report.