The traditional approach has been to force Detroit to clean up what comes out of tailpipes. That strategy worked–sort of. Twenty years after the original Clean Air Act, vehicles spew out 96 percent fewer hydrocarbons and 76 percent less nitrogen oxides (NOx’s), which react in sunlight to form smog. But these gains have been swamped by huge increases in the number of cars on the road, up 51 million from 1970 to 1988. As a result, cars are still the single largest source of urban carbon monoxide and smog. Congress and the White House therefore decided to take aim not only at exhaust pipes, but at fuel tanks. “The only cost-efficient way to solve the problem,” says Charles Gray, who heads the alternative-fuels laboratory at the U.S. Environmental Protection Agency, “is to use fuels that don’t produce dirty emissions.”
Under the House bill, which must be reconciled with a similar Senate version, gas stations in the nine areas with the dirtiest air[*] will have to sell only “clean” gasoline by 1995. “Clean” is defined as having 2.7 percent oxygen by weight. Oxygen makes gasoline burn more completely, reducing dirty emissions. Oxygen can be increased by adding methanol (wood alcohol from natural gas, coal or wood), ethanol (grain alcohol, usually from corn or sugar) or compounds made from either and known as MTBE and ETBE. The fuels provision had strong backing from farm groups, since increasing the market for ethanol should increase the demand for corn.
Whatever the additive, drivers won’t notice much change. Their engines won’t require any conversion and “clean” gas will cost only pennies per gallon more than regular unleaded. Vehicles may even perform better, since MTBE and ETBE, already in use, boost octane.
Unfortunately, this painless route to clean air is not too effective. Although oxygen-rich gasoline can reduce carbon-monoxide emissions by about 25 percent or more in the cities where it’s required, the gases that combine to form smog will drop by only 15 percent, not enough to bring all cities into compliance with clean-air standards. And if ethanol is made from corn, the oil that powers the tractors and the natural gas that produces the fertilizer to grow the crop may dirty rural air enough to offset gains in the cities. “Reformulated gasolines are not entirely clean,” says Daniel Weiss of the Sierra Club, “but significantly cleaner than the existing stuff.” And no matter what their oxygen content, all petroleum-based fuels exacerbate the greenhouse effect. “There’s just no way to touch that problem with reformulated gas,” says James MacKenzie of the environmental-research group World Resources Institute.
Government gas: Big Oil has spent millions of dollars to advertise and lobby against what it calls “government gasoline” because, says Gus Ensz of the American Petroleum Institute, “we object to Congress writing a specific chemical formula [oxygen content] for gasoline.” But Congress didn’t. Refiners can reduce emissions of certain noxious gases, as the House bill also requires, however they like. And they can produce oxygenated clean fuel either by adding 7 percent methanol or ethanol, or spiking regular unleaded with about 15 percent ETBE or MTBE. Either way, every time a service station sells a gallon of fuel that isn’t pure petroleum, oil firms will see revenue go elsewhere. (Some will head for agribusiness giant Archer Daniels Midland, which controls more than 50 percent of the ethanol market.) Oil would have taken a worse beating if Congress had mandated vehicles running on methanol, natural gas or electricity, all of which are cleaner than oxygenated fuels (table)–and not made from petroleum.
Originally, President Bush proposed requiring 1 million “ultraclean” vehicles on the roads by the end of the decade. But the House bill requires that, by 1994, municipalities in southern California operate only 150,000 ultraclean city buses, trucks and cabs. Moreover, “ultraclean” is in the eye of the beholder. To House lawmakers, it means any vehicle spewing out 50 percent less pollution than the legal maximum. Industry can achieve that through tailpipe tinkering, slight alterations in the recipe for gasoline and a preheated catalyst, for a few hundred dollars per car. To environmentalists, “ultraclean” means vehicles running on natural gas or electricity. Says Weiss, “The clean-cars deal is a step forward, but hardly a breakthrough.”
Speed record: Science has already shown that what sounds like sci-fi is eminently feasible, and truly clean fuels are powering cars today. Half a million vehicles worldwide have driven 23 billion miles on compressed natural gas; natural-gas buses and UPS trucks are running in New York City. Besides producing less smog, natural-gas vehicles emit less greenhouse gases than gasoline. California has ordered 10,000 plug-in electric vehicles by 1995. Isuzu Motors Ltd. just announced development of a “revolutionary” battery that could serve as the basis for a better electric car: smaller and more powerful than existing storage devices, it can be recharged in 30 seconds, rather than the hours that today’s batteries require. And this year General Motors unveiled the sporty electric Impact, which has a range of 120 miles and top speed of 100 mph.
Nothing short of weaning vehicles from petroleum will do much about the eye-watering ozone and choking smog that blight our cities. Growth in auto travel, about 3 percent per year nationally, will quickly offset any gains from new fuels. Even worse, the fuel law may become a detour away from an environmentally sound transportation policy, one mandating urban car pools and expanding mass transit. The new fuels can serve as a bridge between dirty gasoline and such truly clean energy sources as solar electricity and hydrogen. For those futuristic technologies to become practical, though, it will require more funding for research into such renewables, which was slashed by the Reagan administration. Only then can we breathe easier about the nation’s air.
[*] Los Angeles, New York, Houston, Baltimore, Chicago, Milwaukee, Philadelphia, San Diego and most of Connecticut.
Vehicles don’t have to run on petroleum. The alternatives are generally cleaner, but some have safety or economic drawbacks. All comparisons are to gasoline:
Fuel (Source) Benefits Drawbacks Methanol 35% to 50% fewer With only half the (natural gas, hydrocarbons, up energy content of coal, wood) 10% less CO[sub2], gasoline, needs bigger and 30% to 40% tanks or refuelings. Can be fatal if ingested absorbed. Compressed 50% to 90% fewer Can cost $2,300 to natural gas hydrocarbons, up to 90% convert a car to (natural gas) less CO, about 15% less CNG.Refueling slow, CO[sub2]. Cheaper than heavy fuel tank gasoline. hurts performance. Ethanol Mixed with gasoline, Some formulations (usually lowers CO 25%, smog can increase smog. corn or sugar) about Less energy per gallon, 15% CO[sub2] so requires more about 5%. Abundant frequent fill-ups. sources, high octane (105). Electricity Almost no emissions. Range limited to (solar, nuclear Overall environmental about 100 miles or fossil fuel) depends on source. with current technology, speed to 65 mph. Recharge slow.
