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Julian Marshall

If Minnesota cleans up its electricity sector, it can realize a significant reduction in greenhouse gas emissions by using more plug-in hybrid vehicles, says researcher Julian Marshall.

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U transportation researchers urge immediate action on greenhouse gas emission goals

By Elizabeth Giorgi, Gina Baas, and Deane Morrison

July 29, 2008

The state of Minnesota can reach and even exceed its goals for reducing greenhouse gas emissions, but only if it acts immediately. So concludes a University study of whether emissions from the transportation sector could actually meet goals set by the Minnesota Legislature in the Next Generation Energy Act. The act calls for overall greenhouse gas emissions to drop by 15 percent (compared to 2005 levels) by 2015, 30 percent by 2025, and 80 percent by 2050. The report and a video of the project are available online. If the state promptly employs a combination of strategies, the transportation sector can nearly meet the 2015 goal and exceed the 2025 goal, the researchers concluded. "The emission reduction goal is achievable if action starts today," says Robert Johns, director of the University's Center for Transportation Studies (CTS). He and CTS Associate Director Laurie McGinnis, a study researcher, say that if the state requires fuel-efficient vehicles, that will not only help in meeting the goals but make Minnesota a national leader in reducing greenhouse gas emissions. The researchers say that the majority of the changes don't require any costly or new technologies. "There is a misconception that it is not possible to make these changes because it isn't affordable," says Julian Marshall, assistant professor of civil engineering and researcher on the study. "In fact, these methods can be used and save people a lot of money and fuel. Energy efficiency can help consumers and benefits the economy, especially with high gas prices."

"One thing that surprised me is how far behind our fuel efficiency standards are compared to the rest of the world--that is, Europe, Australia, and China. China's standards today are more stringent than [proposed U.S.] standards for 2020."

"The technology to make this happen exists, it is just a matter of using it," says David Kittelson, professor of mechanical engineering and study researcher. "The engines we use in our cars are no worse or better than the engines they have in passenger cars in Japan or Germany. The difference is, we put our engines in enormous cars." The public can help by buying fuel-efficient vehicles; living close to their workplaces; commuting by foot, bicycle, carpool, or public transportation; and lowering driving speeds, the researchers say. Transportation accounts for only about 24 percent of total per capita greenhouse gas emissions in Minnesota, compared to more than 28 percent nationally, Marshall says. But that figure isn't due to Minnesotans driving less; it's because the state's total per capita greenhouse gas emissions are high: 30 million tons vs. 24 million tons nationally, on an annual basis. The difference is largely due to Minnesota's reliance on coal-fired power plants, which supply much of the state's electricity. "We have a lot of room to improve," Marshall observes. "If we clean up the electricity sector, we can get a significant benefit from switching to plug-in hybrids. "One thing that surprised me is how far behind our fuel efficiency standards are compared to the rest of the world--that is, Europe, Australia, and China. China's standards today are more stringent than [proposed U.S.] standards for 2020. This is an American competitiveness issue. This [situation] makes our economy less efficient." The 2025 goals are more easily achievable because of lag in the system, Marshall explains. Not everyone will buy more fuel-efficient cars immediately, and it takes time to switch large-scale power production to cleaner technologies. Fuels derived from renewable, but nonfood, resources such as corn stalks and prairie grasses must also be used, the researchers say. An efficient biofuel derived from such sources could achieve 27 percent of Minnesota's reduction goals by 2015. The study also suggests improving fuel economy for heavy-duty vehicles by refining aerodynamics, using lower rolling-resistance tires, and reducing speed. Those changes could contribute about 13 percent of the transportation sector's reduction goal by 2015. There could be an even greater emission reductions if goods are shipped by rail and boat rather than by truck or airplane.