CHARACTERISTICS

The large majority of motor vehicles in use today are internal combustion and diesel engines operating on petroleum and petroleum products. These engines are inefficient and emit a variety of air pollutants, including CO₂. In fact, 31% of all man-made CO₂ emissions in the U.S. derive from petroleum-based motor vehicles.

Utilities operate large fleets of vehicles, including cars, vans and trucks of many types and sizes. Options exist for reducing CO₂ emissions from these vehicles by using alternative fuels. For example, petroleum-based motor vehicles can be substituted with: compressed natural gas or liquefied petroleum gas vehicles, hybrid vehicles, alcohol fueled (neat or mixed with petroleum) vehicles, electric vehicles, and in the near future, fuel cells. In each case, fuels with less carbon content are substituted for petroleum.

However, non-petroleum based options may cost more than conventional motor vehicles and require the construction of infrastructure (alternative fuel filling stations or, in the case of electric vehicles, charging stations) to be viable options. The viability of reducing CO₂ emissions by using electric vehicles is dependent upon how clean the power plants are that provide the electricity to be used by the vehicles.

SIZE:
Applicable for most any type of vehicle (automobiles, trucks, buses).

FEATURES:
Alternative fuels include compressed natural gas (CNG), liquefied petroleum gas (LPG), alcohol fuels (e.g. ethanol). Non-carbon fuel vehicles include electric vehicles. Technologies under development include hybrid and fuel cell vehicles.

COST:
Retrofit of existing and purchase of new automobiles for natural gas can cost an additional $1,500 or more per vehicle. Electric vehicles may cost $1,000 to $3,000 more per vehicle. Fuel switching to alcohol fuels can be done at no extra cost if less than 10% alcohol/petroleum combinations are used.

CURRENT USAGE:
In the U.S., natural gas vehicles are used primarily in auto fleets in major cities that have serious ozone pollution problems. Alcohol fuels are used in the Midwest where federal subsidies are provided to farmers and alcohol fuel producers.

POTENTIAL USAGE:
These options can be used for the majority of motor vehicles. Vehicle technologies under development (e.g., fuel cells, hybrids) may be cost-competitive with traditional fuel sources for vehicles within a number of years.

ISSUES ASSOCIATED WITH IMPLEMENTING ACTION

• The cost of retrofitting existing vehicles or purchasing new vehicles for using non-petroleum fuels is high.
• Limited infrastructure exists for the widespread use of these options.

CLIMATE CHANGE IMPACT

EMISSION EFFECT:
    

CONDITIONS FOR EMISSIONS MITIGATION:

• The CO₂ emissions reductions that result are dependent upon the fuel used, the source of electric power (for electric vehicles), and the options it is replacing (some petroleum-fueled vehicles are more efficient than others).
• If petroleum vehicles currently in use are converted to use non-petroleum fuels, emissions will be reduced. If new/additional vehicles are purchased instead of petroleum vehicles, emissions will be avoided.

EMISSION ESTIMATE:
gasoline—610 g/mi
CNG—500 g/mi
LPG—500 g/mi
electric—480 g/mi
ethanol/wood—100 g/mi

COST-EFFECTIVENESS:
$450-$3,500 additional capital cost/vehicle

SECONDARY EFFECTS:
These options may also reduce NO_x emissions.

RESOURCES

• U.S. Department of Energy, 1997, Scenarios of U.S. Carbon Reductions, Potential Impacts of Energy Technologies by 2010 and Beyond.
• Over a dozen U.S. utilities have significant experience with using non-carbon fuel vehicles, especially electric vehicles, for their fleets. Programs include development of electric vehicles for use by meter readers, pilot programs for electric car battery trade-ins. Some utilities have committed to building infrastructure to support the use of CNG vehicles to further develop their use.

CONTACTS

U.S. Department of Energy
Electrical Vehicle Program
Pandit Patil
Office of Advanced Automotive Technologies
Washington, DC
Tel: (202) 586-6055
http://www.ott.doe.gov/oaat/

Idaho National Engineering & Environmental Laboratory
EV America Program
Idaho Falls, ID
http://www.inel.gov/