MIT recommends steps to slash gasoline use by 2035

It's feasible—but challenging on many fronts

How much gasoline would the nation save in the year 2035 if lightweight hybrid and plug-in hybrid vehicles dominated the marketplace? More than 68 billion gallons, or about half the fuel currently used by today's vehicles.

Detailed analyses in a new MIT report demonstrate that such changes are feasible. Indeed, the report concludes that over the next 25 years the fuel consumption of new vehicles could be reduced by 30-50 percent and total U.S. fuel use for vehicles could be cut to 2000 levels, with greenhouse gas (GHG) emissions cut by almost as much.

Accomplishing such changes will require not just developing improved and new engines, vehicles, and fuels but also convincing people that they don't need to buy bigger, faster cars. Each step will be difficult, yet all must be pursued with an equal sense of urgency.

"We've got to get out of the habit of thinking that we only need to focus on improving the technology—that we can invent our way out of this situation," said John B. Heywood, the Sun Jae Professor of Mechanical Engineering, who led the research. "We've got to do everything we can think of, including reducing the size of the task by real conservation."

Carefully crafted government policies will be needed to bring about this large-scale move away from business as usual, the researchers emphasize.

The new report, On the Road in 2035: Reducing Transportation's Petroleum Consumption and GHG Emissions, integrates five years' work by MIT teams examining different approaches to cutting transportation fuel use and emissions. Projects analyzed specific propulsion technologies, vehicle performance and design, market penetration rates for the various technologies, consumer expectations, new fuels, and potential policy measures.

Each project involved quantitative analysis of potential gains and when those gains might come. Integrating the studies allowed a broad system perspective. For example, teams calculated the fuel economy and emissions gains achievable with, say, hybrid technology. Then, using analyses of cost and consumer preferences, they projected how rapidly sales volumes of hybrids may build up and how much total U.S. gasoline consumption would decline as a consequence.

"That last task is very important because unless you've got lots and lots of vehicles with the better technology, the impact is limited," said Heywood. "The need to bring better technology into production and build up volume inevitably makes the time frames for technologies to make a difference long. Optimists want to move faster, but it's not clear we can really do it much faster."

Slashing transportation fuel use and GHG emissions by 2035 will require immediate action on several challenging fronts. The following steps are key.

For the near term (up to 15 years), we should increase our efforts to improve light-duty vehicle engines and transmissions, but all improvements must go towards reducing fuel efficiency rather than making cars bigger and faster. Also critical is reducing vehicle weight and size.

For the mid and long term (15-30 years, and more than 30 years), we should ramp up work on radically different technologies such as plug-in hybrids and hydrogen fuel cell vehicles.

We must also develop and market more environmentally benign fuels based on non-petroleum sources. For example, research on biofuels should continue. The US emphasis on corn-based ethanol is not obviously justifiable, but biofuels based on other feedstocks and conversion technologies should be pursued. In general, the use of biofuels will grow but not as fast as expected just a few years ago.

The final key is policy action. A coordinated set of regulatory and fiscal measures will be needed to push and pull improved technologies and greener alternative fuels into the market place in high volume. Measures should require auto manufacturers to make smaller, more-efficient cars, encourage consumers to choose those vehicles, and discourage everyone from driving so much.

Overall, the report shows that there are many opportunities for change. However, the challenges involved are enormous.

"Transitioning from our current situation onto a path with declining fuel consumption and emissions, even in the developed world, will take several decades—much longer than we had hoped or realized," said Heywood. "We've got to start now."

Other authors on the report are Anup Bandivadekar, MIT PhD 2008 (Engineering Systems Division, ESD); Kristian Bodek MS 2008 (Technology and Policy Program, TPP); Lynette Cheah, graduate student in ESD; Christopher Evans MS 2008 (TPP); Tiffany Groode PhD 2008 (Department of Mechanical Engineering); Emmanuel Kasseris, graduate student in Mechanical Engineering; Mathew Kromer MS 2007 (TPP); and Malcolm Weiss of the MIT Laboratory for Energy and the Environment. The authors are members of MIT's Sloan Automotive Laboratory, of which Heywood is director, and are involved in the MIT Energy Initiative.

The full report plus its predecessor On the Road in 2020 (published in 2000) and related theses, conference papers, journal articles, and news articles are available at the Fueling our Transportation Future website.

—Nancy Stauffer, MIT Energy Initiative

This research was supported by Concawe, Eni S.p.A., Environmental Defense, Ford Motor Company, the Alliance for Global Sustainability, the MIT-Portugal Program, and Shell Oil Company.

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John B. Heywood, the Sun Jae Professor of Mechanical Engineering, has led research examining different approaches to cutting transportation fuel use and emissions. He and his colleagues recently released a comprehensive report that integrates findings from five years' work.Enlarge image

MIT assessments of various propulsion technologies yielded these estimates of their potential fuel consumption in 2035. The analyses assumed that these new cars—to be sold in the United States—have the same performance and interior size as today's average mid-size car. The 2035 vehicles have more efficient engines and transmissions, 20 percent lower weight, and reduced drag and tire resistancesEnlarge image