HR: 0800h
AN: A31B-0061    [Abstracts]
TI: The Effect of Converting to a U.S. Hydrogen Fuel Cell Vehicle Fleet on Emissions and Energy Use
AU: Colella, W G
EM: wcolella@alumni.princeton.edu
AF: Department of Civil and Environmental Engineering, Terman Engineering Center Stanford University, Stanford, CA 94305-4020 United States
AU: * Jacobson, M Z
EM: jacobson@stanford.edu
AF: Department of Civil and Environmental Engineering, Terman Engineering Center Stanford University, Stanford, CA 94305-4020 United States
AU: Golden, D M
EM: david.golden@stanford.edu
AF: Department of Mechanical Engineering, Building 520 Stanford University , Stanford, CA 94305-3030 United States
AB: This study analyzes the potential change in emissions and energy use from replacing fossil-fuel based vehicles with hydrogen fuel cell vehicles. This study examines three different hydrogen production scenarios to determine their resultant emissions and energy usage: hydrogen produced via 1) steam reforming of methane, 2) coal gasification, or 3) wind electrolysis. The atmospheric model simulations require two primary sets of data: the actual emissions associated with hydrogen fuel production and use, and the corresponding reduction in emissions associated with reducing fossil fuel use. The net change in emissions is derived using 1) the U.S. EPA's National Emission Inventory (NEI) that incorporates several hundred categories of on-road vehicles and 2) a Process Chain Analysis (PCA) for the different hydrogen production scenarios. NEI: The quantity of hydrogen-related emission is ultimately a function of the projected hydrogen consumption in on-road vehicles. Data for hydrogen consumption from on-road vehicles was derived from the number of miles driven in each U.S. county based on 1999 NEI data, the average fleet mileage of all on-road vehicles, the average gasoline vehicle efficiency, and the efficiency of advanced 2004 fuel cell vehicles. PCA: PCA involves energy and mass balance calculations around the fuel extraction, production, transport, storage, and delivery processes. PCA was used to examine three different hydrogen production scenarios: In the first scenario, hydrogen is derived from natural gas, which is extracted from gas fields, stored, chemically processed, and transmitted through pipelines to distributed fuel processing units. The fuel processing units, situated in similar locations as gasoline refueling stations, convert natural gas to hydrogen via a combination of steam reforming and fuel oxidation. Purified hydrogen is compressed for use onboard fuel cell vehicles. In the second scenario, hydrogen is derived from coal, which is extracted from mines and chemically processed into a hydrogen rich gas. Hydrogen is transmitted through pipelines to refueling stations. In the third scenario, hydrogen is derived via electrolysis powered by wind-generated electricity that has been transmitted across the country to electrolyzers at distributed hydrogen refueling stations. If hydrogen is produced via the first scenario, total annual U.S. production of carbon dioxide (CO2) could be expected to decrease by approximately 900 million metric tons, or 16 percent of annual U.S. CO2 production from all anthropogenic sources. Under this scenario, compared with the conventional vehicle fleet, a fuel cell vehicle fleet would produce some additional CO2 emissions due to the electric power required for the compression of hydrogen, but less CO2 emissions on the road during vehicle operation. This scenario results in an additional methane leakage of approximately one million metric tons per year, or 4 percent of annual U.S. methane emissions from all anthropogenic sources.
DE: 6620 Science policy
DE: 3309 Climatology (1620)
DE: 1610 Atmosphere (0315, 0325)
DE: 0315 Biosphere/atmosphere interactions
DE: 0325 Evolution of the atmosphere
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting