Wheels: No Silver Bullet for Reaching Fuel and Emissions Goals, Study Says

Rebecca Cook/Reuters “Limited range and long recharge times are likely to limit the use of all-electric vehicles mainly to local driving,” a report from the National Research Council says.

The United States could possibly achieve the goal of an 80 percent reduction in oil use and greenhouse gas emissions from cars and small trucks by 2050, but it will not be easy, a National Research Council report said.

Simply making conventional vehicles more fuel efficient cannot by itself bring the target within reach, the report, which was released on Monday, says. Average fleet fuel economy “would have to exceed 180 m.p.g.,” which “is extremely unlikely, at least with current identifiable technologies,” says the report from the council, which is an arm of the National Academy of Sciences.

The committee preparing the report focused on vehicles running on electricity, biofuels or hydrogen, as well as conventional cars and trucks with high-efficiency gasoline technology. The committee concluded that the wide deployment of at least two of them would have to be combined with strong federal policy if the goal were to be met. Natural gas vehicles were given credit for their ability to reduce oil consumption, but were faulted for their limited impact on carbon dioxide emissions.

“There’s no single pathway, no silver bullet adequate by itself to meet the goals,” Douglas M. Chapin, chairman of the committee, said in a conference call. “The goals are difficult but not impossible to meet if supported by strong national policies.” He added that even partial success “will yield valuable benefits.”

Government initiatives, the report says, could include fuel economy standards tougher than the federal goal for 2025 of 54.5 miles per gallon; support for research and development; rebate incentives for buyers of efficient cars and surcharges for inefficient purchases; and campaigns to familiarize consumers with the new options.

The report is somewhat pessimistic about electric car progress. Although battery costs may drop, the report said that “limited range and long recharge times are likely to limit the use of all-electric vehicles mainly to local driving.” Advanced battery technologies are being developed, it said, “but all face serious technical challenges.”

John M. German, senior fellow at the International Council on Clean Transportation, said in the conference call that the committee projected that the energy density of lithium-ion batteries could be two to three times greater than it was today and that the cost of a battery pack a quarter as much.

By 2050, vehicles with 100-mile-range batteries and hydrogen power could become cheaper than cars and trucks with advanced internal-combustion drivetrains, the report says. But there are other challenges. Fuel-cell vehicles avoid the range and recharging limitations of electric vehicles, the report says, but building a network of expensive hydrogen stations will be “difficult and expensive.”

Cellulosic biofuels show some promise and could lead to big reductions in oil use and greenhouse gas emissions, but “achievable production levels are uncertain,” the report says. It also envisions a possible future for biofuels that can be refined into a product that is chemically similar to gasoline.

The report also looked beyond the tailpipe. “To really impact automotive greenhouse emissions, you have to control energy sector emissions, starting with the oil and gas sector today and from power plants as electric cars enter the market,” John DeCicco, a committee member and research professor at the University of Michigan Energy Institute, said in a telephone interview.