Fuel Economy Standards

Fuel Economy Standards

The U.S. recently announced new, aggressive fuel economy standards for 2017 to 2025. Among them, a new regulation aimed at doubling average vehicle fuel economy to approximately 55 miles per gallon by 2025.

Experts at Carnegie Mellon University shed light on what these standards really mean to both consumers and auto makers — and how CMU's technology will play a role.

"The increased Corporate Average Fuel Economy (CAFE) standards will incentivize the use of fuel-saving technologies and improve vehicle efficiency. That's a good thing. But the policy is far from perfect," said Jeremy Michalek, associate professor of mechanical engineering and engineering and public policy.

For instance, Michalek explains, consumers should know that the CAFE policy relies on an old test to measure fuel efficiency — not the same test they use for vehicle window stickers.

"While politicians can claim that we've set high-sounding standards of 55 mpg using the outdated tests, consumers will see real numbers closer to 35 miles per gallon. And these averaged numbers ignore that while highway drivers may see little or no benefit from hybrid and plug-in vehicles, city drivers could benefit greatly," said Michalek. 

Second, he noted, the policy is designed to rely entirely on technology improvements to provide reductions rather than any changes in driving patterns or fleet mix — for example, cars vs. SUVs.

"The policy could incentivize drivers to drive more and auto makers to produce larger vehicles, both of which would be counterproductive," said Michalek. "Ideally, a more efficient approach would be to apply an economy-wide tax on gasoline consumption and emissions that reflect the social costs they cause. Consumers would then have a choice in how to respond — by buying a high-efficiency vehicle, buying a smaller vehicle, driving less, or paying for the social costs caused by driving."

Michalek added, "And revenue generated from such a policy could be used to reduce taxes on things we want to encourage, like employment."

Chris T. Hendrickson, the Duquesne Light University Professor of Civil and Environmental Engineering, says that vehicle energy efficiency is important not only for environmental reasons but also to reduce dependence on imported petroleum. 

"CAFE can play a significant role, but the standards are only one avenue to influence vehicle design and performance to improve vehicle energy efficiency."

Others, Hendrickson says, include shifting to renewable power generation, improved federal procurement practices, and research support for new technologies. Michalek agrees.

"New technologies can only make an impact to the extent that people adopt them," he said. "We need innovative advancements to reduce the costs of alternative vehicles, improve their attributes, and make them more competitive in the marketplace."

According to Michalek, the largest barrier to hybrid and electric vehicle adoption is the high cost of batteries. Development of lower cost, longer lasting, compact, high-power batteries can make hybrid and electric vehicles more viable and increase adoption, he said.

And this kind of new technology development is already in the works at CMU.

For instance, Shawn Litster, a CMU assistant professor of mechanical engineering, is studying and improving electrodes for batteries and fuel cells. Jay Whitacre, CMU associate professor and founder of startup company Aquion Energy, is focused on electricity storage systems. Illah Nourbakhsh, a professor in CMU's Robotics Institute, is building electric vehicles with CMU's ChargeCar group. And Michalek's group is developing methods to improve vehicle fuel economy.

"Getting there requires a mix of fundamental research, to understand what is happening inside battery electrodes and across interfaces; applied research, to make a better battery system; and analysis to understand broader implications and set goals," said Michalek.

He added, "Getting there also requires a systems perspective and interdisciplinary collaboration, which are among Carnegie Mellon's core strengths."

CMU President Jared L. Cohon is chairing a National Research Council Committee on Fuel Economy of Light-Duty Vehicles, which is examining the CAFE standards.


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