Carnegie Mellon Researchers Find Win-Win Situation
With Small-Capacity Plug-In Hybrid Vehicles
PITTSBURGH—A team of researchers at Carnegie Mellon University report in a new study that some plug-in hybrid electric vehicles could help drivers save money while addressing global warming and oil dependency.
"When charged frequently, plug-in hybrid vehicles with small battery packs offer the largest reductions of greenhouse gas emissions, gasoline consumption and lifetime vehicle cost," said study leader Jeremy J. Michalek, an assistant professor of mechanical engineering and engineering and public policy at Carnegie Mellon.
Plug-in hybrid vehicles use battery packs to store energy and propel the vehicle partly on electricity instead of gasoline. "On average, electric power creates fewer greenhouse gas emissions per mile than gasoline in the U.S., and larger battery packs allow drivers to go farther on electric power. But batteries are expensive, and their extra weight lowers the vehicle's efficiency," Michalek said.
The study used computer simulation models to account for the weight and cost of plug-in battery packs. "We looked at a wide range of scenarios from fluctuating gasoline prices to new battery technology and carbon taxes. The core conclusion is consistent: For urban drivers who charge frequently — every 20 miles or less — plug-in vehicles with small battery packs sized for about seven miles of electric travel per charge can reduce gasoline consumption, greenhouse gas emissions and lifetime cost. For those who can't charge often, large-capacity plug-in vehicles sized for 40 or more miles of electric travel will still reduce gasoline consumption and greenhouse gas emissions, but at a higher lifetime cost," said Michalek.
President Barack Obama has set a target of one million electric cars on U.S. roads by 2012. To meet that goal, industry experts estimate that automakers will need about $40 billion worth of domestically produced batteries. Battery makers are expected to get some of the $25 billion set aside last year under Washington's Advanced Technology Vehicle Manufacturing Program to speed the commercialization of green cars.
"Often new technologies are initially more expensive than established technologies. What's encouraging is that today's plug-in technology appears to offer some drivers the chance to save money while addressing oil dependency and global warming," Michalek said.
Pictured above is Jeremy J. Michalek, an assistant professor of mechanical engineering and engineering and public policy at Carnegie Mellon.