SALT LAKE CITY — A thought-provoking air quality study released this month gives car consumers a lot to ponder as they fill up the gas tank, plug in their vehicle or stop for a refueling at a compressed natural gas station.
To be entirely environmentally friendly — in consideration of the full range of "life cycle" air pollution impacts — an electric vehicle that gets its charge from coal-fired power plants is a worse choice than a conventional gas-powered vehicle, according to the analysis.
That finding in the University of Minnesota study sent local clean air and electric vehicle advocates into a frenzy to try to counter what they say is the wrong message for the Wasatch Front.
"While we don't disagree with the study in general, it lacks some of the specificity of our local air quality story about tailpipe emissions and their impact along the Wasatch Front," said Kevin Emerson, senior policy and regulatory associate for Utah Clean Energy. "Electric vehicles have immediate air quality benefits and will continue to have even greater benefits here. We don't want that to get lost."
The study, published Dec. 15 in the Proceedings of the National Academy of Sciences, looked at how concentrations of particulate matter and ground-level ozone change as the result of using the various options for powering vehicles.
Researchers investigated the 10 alternatives to conventional gas-powered vehicles and found that electric vehicles — powered by electricity generated from natural gas, wind, water or solar power — are the best at improving air quality, while vehicles powered by corn ethanol and electric vehicles powered by coal are worst.
What the research looked at are the greenhouse gas emissions and other pollutants that come from coal-fired power plants, as well as emissions generated from coal mining in general.
"We find that powering vehicles with corn ethanol or with coal-based or 'grid average' electricity increases monetized environmental health impacts by 80 percent or more relative to using conventional gasoline," said the study by researchers Christopher W. Tessuma, Jason D. Hill and Julian D. Marshalla. "Conversely, (electric vehicles) powered by low-emitting electricity from natural gas, wind, water or solar power reduce environmental health impacts by 50 percent or more."
In a state like Utah — which gets 81 percent of its electricity from coal — the study's assertions may make electric cars seem a poor choice to help fix the Wasatch Front's dirty air problem, but advocates say otherwise.
"The really important point is that because those coal-fired power plants that are powering the Wasatch Front are all outside the (pollution) non-attainment areas and pretty far outside Salt Lake City, they are not contributing to the air quality issues that the Wasatch Front is suffering from," said Mike Salisbury, transportation program associate with the Southwest Energy Efficiency Project.
"You kind of lose how air quality works in Salt Lake City when you say coal-fired power plants are bad, but that is not the case," added Salisbury. "The air quality benefits are pretty significant over gas-powered vehicles along the Wasatch Front."
The Southwest Energy Efficiency Project, which promotes energy efficiency in a six-state region that includes Utah, conducted an analysis last year that looked at Wasatch Front-specific benefits in emission reductions that would occur if an electric vehicle were used over a new gasoline vehicle.
In the study, authored by Salisbury in partnership with Utah Clean Energy, the analysis points to reductions of:
Nearly 100 percent in volatile organic compounds.
76 percent in nitrogen oxides.
65 percent in small particulates.
95 percent in sulfur dioxides.
Both Emerson and Salisbury stress that they don't disagree with the basic premise of the Minnesota study that concludes electric vehicles powered by renewable energy are best at reducing pollution.
"But the upstream emissions from electric vehicles are not contributing to those air quality problems on the Wasatch Front," Salisbury said.
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