Seeking the Best Fuel for Fuel Cell Vehicles
Office of Advanced Automotive Technologies July 2002 report
Goal: Compare the feasibility, efficiency, cost, and safety of generating hydrogen at fueling stations with in-vehicle reforming of hydrocarbon fuels
The U.S. Department of Energy (DOE) has supported the development of polymer electrolyte membrane fuel cells for transportation applications for more than a decade. DOE initially focused on a strategy in which gasoline is processed to generate hydrogen onboard the vehicle, but now off-board production and onboard storage of hydrogen is being considered as a possible ultimate solution. To assess the trade-offs between the two strategies, DOE commissioned TIAX LLC (formerly Arthur D. Little, Inc., Technology and Innovation) to evaluate their relative merits.
Scope of Work
TIAX developed a detailed well-to-wheel performance and cost assessment that incorporated Argonne National Laboratory's GREET model into the company's proprietary methodology. The study developed a thorough analysis of fuel cell power unit and vehicle performance. TIAX researchers determined fuel and vehicle ownership costs on the basis of a detailed analysis of the cost of onsite hydrogen fueling stations and fuel cell components. They also identified and compared potential safety issues for each option.
Fuel economy is based on future scenarios for vehicle performance consistent with expected results of current research and development. Fuel economy for internal combustion engine vehicles (ICEVs) is based on current technologies, and that for hybrid electric vehicles (HEVs) is based on a round robin consensus of future improvements. Fuel costs are based on DOE Energy Information Administration (EIA) price projections and bottom-up estimates for hydrogen and other alternative fuels. Hydrogen fuel costs are based on the assumption that a hydrogen station produces 690 kg/day and onsite equipment is manufactured or purchased at a volume of 100 units per year.
Results and Future Plans
Only a sampling of the results of the analysis is presented here. The full report is available online.
Estimated well-to-wheel energy use for various types of fuels and vehicles.
Well-to-Wheel Energy Use Results
Direct-hydrogen fuel cell vehicles (FCVs) carrying compressed hydrogen produced from natural gas consume the least well-to-wheel energy — half that of gasoline ICEVs.
Gasoline FCVs with an onboard reformer could achieve a 40% lower well-to-wheel energy consumption than ICEVs..
The use of methanol in FCVs would lead to a 20% higher well-to-wheel energy consumption than gasoline FCVs because of significant losses in fuel production.
The inefficiency of ethanol production results in ethanol FCVs having a 10% higher well-to-wheel primary energy consumption than ICEVs.
All-battery electric vehicles could consume about 30% less well-to-wheel energy than conventional ICEVs but are not likely to achieve the performance and range possible with ICEVs and FCVs.
Fuel Price Results
The most economical hydrogen fueling scenarios cost around $15-20/GJ delivered to the vehicle (without taxes), which is two to three times more than gasoline before taxes.
According to EIA energy price projections, electrolyzer-based hydrogen production is costly, resulting in a hydrogen cost of around $40/GJ (without taxes).
High-volume ethanol production and distribution would result in a cost of around $15-17/GJ (without taxes) — twice as much as gasoline.
Future methanol price projections overlap with those for gasoline, making it the least costly alternative fuel considered in this study.
Alternative fuels, especially hydrogen, will require significant upfront investment, representing a financial risk to both vehicle manufacturers and fuel providers.
Safety Analysis Results
Safety issues concerning hydrogen transportation, fueling stations, and onboard storage and use can likely be resolved without onerous cost increases.
However, FCVs will require modifications to garages, maintenance facilities, and on-road infrastructure that could be costly and difficult to implement
In Phase III of the program, TIAX researchers will evaluate the effect of various fuel choices on the current fuels infrastructure and assess the financial risk associated with the various fueling options.
Research Partners
TIAX, LLC (formerly Arthur D. Little, Inc., Technology and Innovation)
cartech.doe.gov ... original link c/w graphs |
