Experts see limits to “moon shot” approach for reducing car emissions.

President Barack Obama will propose that the US dramatically reduces greenhouse emissions when he attends the United Nations Climate Change Conference next month in Copenhagen. His proposed target is to reduce total emissions by 17 percent over 2005 levels by 2020. According to the administration, a big chunk of the reductions will come from improving vehicle fuel efficiency.

Early in his administration, Obama announced new fuel economy targets of 35.5 miles per gallon in 2020—a 40 percent increase from today. But how exactly do we make that 40 percent jump?

One avenue is switching to plug-in hybrid and electric cars as soon as possible. To push in that direction, the Obama Administration awarded $2.4 billion in grants for advanced batteries and electric vehicle research. But many experts say that electric and hybrid cars are unlikely to be sold in high enough numbers in the next decade to have much of an impact.

The Wall Street Journal reported today that “the fight to curb fossil-fuel consumption has often involved moon shots.” The article points to experts who say the smarter strategy is using unglamorous low-tech solutions. “The energy problem,” said Steven Chu, the US energy secretary, “can be advanced a long way by pretty low-tech stuff.” This view pushes the auto industry toward ho-hum solutions, like improving the efficiency of gas engines, making cars smaller and lighter in weight, improving aerodynamics, and offering new incentives for today’s most efficient gas-consuming cars, like hybrids.

Revolutionary versus Evolutionary Technologies

More evidence about the importance of low-tech solutions emerged this past summer, when a group of Silicon Valley technology investors looked at nine different emerging technologies—from biofuels and building efficiency to geothermal and nuclear—to determine which ones were capable of reducing annual emissions of greenhouse gases by 1 billion metric tons—a gigaton—by 2020. In a report called the Gigaton Throwdown, referenced by the Wall Street Journal, the group gave a thumbs up to improving the efficiency of existing buildings—but said that plug-in hybrid cars, one of the nine technologies—wouldn’t reach the gigaton threshold.

The Silicon Valley group said the only way plug-in hybrids could slash emissions by a gigaton by 2020 is if every single new car sold starting in 2010 were a plug-in hybrid. The report concludes, “This number is not possible based on any reasonable vehicle introduction and ramp-up strategy.”

The implications for government officials and the auto industry are to use a host of strategies, rather than single-point high-profile technologies like plug-in cars. The introduction of plug-in hybrids and electric cars must be developed in concert with improving the efficiency of gas-powered cars, reducing the amount people drive, and using “feebates” and other incentives to encourage sales of cars with higher mpg.

Fans of plug-in hybrids and electric cars might need to reset their expectations but should not be discouraged. The Silicon Valley group said, “In the longer term, by 2040 or 2050 and with more time for new vehicles to enter the fleet, some combination of electric drive vehicles that includes plug-in hybrids, battery electric vehicles, and fuel cell vehicles, could achieve [targeted] emission reductions.”