Metro Denver’s 49 ozone alerts last summer set an all-time record as air pollution cooked in the sun and irritated the lungs of residents. Now our winter season air pollution looms, caused largely by carbon monoxide and other emissions from auto tailpipes.
Among the most unhealthy substances in the air we breathe are toxic chemical compounds produced in the gasoline refining process and used to improve engine performance. These so-called aromatics, including benzene, toluene and xylene, make up an average of 26 percent of every gallon of gas in our vehicles. After combustion, they contribute carcinogens to our air and help create pollution.
These poisons are one reason why metro Denver may not meet federal ozone standards by next year. A healthier alternative needs to be explored, and it may be as close as our neighboring farms: replacing aromatics with ethanol as a way to boost octane in gasoline. Successfully used in this country for years as a 10 percent blend with gasoline, ethanol represents a promising fuel for our nation’s future.
An EPA model found that a 10 percent ethanol blend can reduce the emissions of benzene by 25 percent compared to regular gasoline. Benzene is the most significant of the toxic pollutants emitted from vehicles, representing nearly 70 percent of total toxic emissions from vehicles using standard gasoline.
Phasing out aromatics could have health benefits nationally worth tens of billions of dollars. The EPA is now considering new rules which would require only a modest decrease in benzene.
While displacing aromatics with ethanol makes sense for the short term, an even better long-term solution lies in moving rapidly toward the use of ethanol as a replacement fuel and not just an additive. Ethanol is cheaper to make than gasoline (with no subsidy) when oil costs more than $60 a barrel, and so the economics are already in favor of this cleaner direction.
High-blend ethanol, known as E-85, is now available on a limited basis to burn in flexible-fuel vehicles. From research done so far, E-85 appears to have clear benefits for reducing toxic tailpipe emissions produced by gasoline and its aromatic components. One study found that toxic emissions from a car tested on E-85 were 55 percent lower than from the same car tested on gasoline.
Colorado could be a leader in this transition, encouraging movement to a cleaner-burning fleet of flex-fuel vehicles which use mostly ethanol. Major auto makers are increasing production, and already in Brazil more than 80 percent of new cars sold by GM and Ford are flex-fuel. Gas stations also need to be encouraged to make E-85 more widely available to consumers by adding pumps at more stations.
Most U.S. ethanol today comes from corn, but advanced technologies using other crops offer greater promise for the long term, especially in dry areas such as Colorado. Recent breakthroughs in biotechnology have cut the cost of making ethanol out of cellulose, the fiber in plants. This new kind of ethanol can be produced from perennial grasses such as switchgrass, and materials now wasted such as wheat straw, thanks to research pioneered at the National Renewable Energy Laboratory in Golden.
These grasses are drought-tolerant and can even generate electricity as they are converted to ethanol. Their potential is vast. In a report last year, Oak Ridge National Laboratory concluded that the U.S. could replace 30 percent of its petroleum consumption from these sources by 2030.
Water-strapped Colorado farmers may be able to produce a substantial portion of the state’s future fuel supply in the form of ethanol from cellulose. Encouraging the development of this fuel of the future thus holds the promise of cleaning the air, invigorating rural Colorado, heightening energy security and providing a more sustainable future.
Tim Wirth is a former U.S. Senator from Colorado and current president of the United Nations Foundation. Kay Lynn Hefley is a farmer in southeastern Colorado active in 25 x ’25, a national movement to get 25 percent of the nation’s energy from renewable sources by 2025.
