Better Mileage.

Better Mileage

WASHINGTON WINDOW

With the price of gasoline increasing rapidly, more from war jitters than actual shortages, the next Congress is likely to take a closer look at alternative motor fuels.

Engines fired by gasoline and diesel fuel emit 66 percent of

the carbon monoxide, 50 percent of the nitrogen dioxide, and 37 percent of the hydrocarbons found in the air we breathe. These pollutants are themselves health problems or contribute to the formation of low-level ozone. At least in theory, these emissions can be reduced by running vehicles on such fuels as methanol, ethanol, natural gas, hydrogen, or reformulated gasoline.

These alternative fuels may be able to reduce ozone levels in urban areas, improve energy security, and reduce emissions of greenhouse gases--but they were a sticking point in the debate between House and Senate conferees over amendments to the Clean Air Act. In October, Congressional staff appear to have resolved the differences, tightening automotive emission standards beginning in 1994.

The package would require a phase-in of 60 percent reductions in nitrogen oxides and 40 percent reductions in hydrocarbons between 1994 and 1996, matching the standards required in 1993 for cars sold in California. Emission-control equipment would have to last 100,000 miles, up from the current 50,000 miles mandated by law.

California would also be the standard for alternative-fuel programs for all states. Under this proposal, if states adopt an alternative-fuel program, it would have to be the California standards for alternative-fuel cars and trucks; states could enforce the program, but pre-manufacture certification would be handled by the Environmental Protection Agency. State and local air quality administrators vigorously opposed this preemption of their authority, while the auto industry opposed having to meet 50 different standards.

Oxygenated gasoline, currently in use in the Denver metropolitan area, would be required beginning in 1992 in all cities that do not meet EPA standards for ambient carbon monoxide. Beginning in 1995, reformulated gasoline with lower volatility, reducing hydrocarbon emissions, would be required in the nation's nine-smoggiest cities.

In late September, in time to influence these considerations, the Congressional Office of Technology Assessment issued a study, Replacing Gasoline: Alternative Fuels for Light-Duty Vehicles. The OTA document compares methanol, ethanol, natural gas, electricity, hydrogen, and reformulated gasoline to each other and to gasoline.

A similar review of these issues was prepared for the Michigan Legislative Science Office earlier this year by E.B. Watson, ASME's former Michigan Legislative Fellow, and Karen East of the Science Office staff.

Internal Combustion

The ironed-out Clean Air Act amendments would create a California pilot program for alternative fuels, including sale of electric cars. By 1998, fleets sold in that state would have to contain a small percentage of zero-emission (i.e., electric) vehicles, but manufacturers would otherwise be allowed to produce any mix of vehicles to meet stringent fleet average standards.

Although all of the alternative fuels offer some potential to improve urban ozone and toxic emissions, the OTA report notes that three offer the largest reductions per vehicle: natural gas, hydrogen, and electricity. The emissions avoided from individual vehicles fueled with hydrogen or electricity must be weighed against those produced while generating the electricity used to split the hydrogen from water or to charge the vehicle's batteries.

Alcohol fuels--methanol or ethanol, by themselves or mixed with gasoline--present the fewest technical problems to refueling cars and light trucks, but offer smaller reductions in air pollutant emissions. Methanol would likely be made from natural gas, ethanol from corn. Both could modestly improve energy security, and ethanol could reduce net greenhouse emissions.

Reformulated gasoline, now likely to be mandated in smoggy areas, requires no vehicle adjustments. The OTA study notes that its use would not improve energy security or reduce greenhouse emissions.

Diesel Data

Watson and East's report to the Michigan legislature, Alternative Fuels for the Combustion Engine (ASME State Government Technical Brief 102-90-MI-1) focused on the impact of alternative fuels on air quality and did not consider the impact on production of greenhouse gases. Unlike the OTA study, the Michigan paper examines the prospects for alternative fuels for diesel engines.

Natural gas (either as compressed natural gas, liquefied petroleum gas, or propane) and methanol have been studied as alternative diesel engine fuels in Canada and the Netherlands. Laboratory tests show that alternative fuels would allow diesel engines to meet the 1994 EPA heavy-duty diesel engine emissions standards for particulates, carbon monoxide, and hydrocarbons; nitrogen oxide levels for propane or natural gas engines might be above these limits without addition of a catalytic control system, however.

The Congressional proposals reflect a change in environmental regulation strategy, according to Watson and East. They wrote, "To date, motor vehicle emission reductions have been achieved under a system in which [the] EPA sets pollutant emissions standards [performance standards] and a timetable for compliance." Mandating the use of alternative fuels would signal a shift from the flexibility of performance standards to the rigidity of technology standards, they also noted.

The OTA report (GPO stock number 052-003-01206-5) can be ordered for $7 from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402-9325; (202) 783-3238. The state government technical brief is available for $5 from State Government Relations, ASME Washington Center, 1825 K St. NW, Suite 218, Washington, DC 20006; (202) 785-3756.