Assessing the Environmental Impact of Operating Electric and Hybrid Vehicles

The dramatically smaller footprint of electric cars varies depending on the source of electricity used to power them. “The types of power plants installed in the next two decades will not only affect how much we can reduce emissions from electricity, but also from vehicles,” said Carnegie Mellon engineer Kyle Meisterling.

Newer fossil fuel powered vehicles are much more efficient than previous generations of automobiles, but they are not as efficient as hybrids or fully electric vehicles.

In places like California where tailpipe standards are some of the toughest in the nation, a 2010 gas powered car puts out only 2 percent of the emissions of a 1980s model. However, electric vehicles have a much smaller carbon footprint than even the most efficient fossil fuel powered vehicles.

We should not underestimate the contributions of electric vehicles to our environment. According to Tom Cahill, a professor emeritus of physics at UC Davis, EVs offer “a whole lot of gain in climate change.”

All-electric vehicles burn no fossil fuels, and hybrids burn relatively small amounts of gas. The tailpipe emissions from electric cars are zero and hybrids have a significantly reduced emissions profile compared to conventional vehicles. In places like Los Angeles, on some days, the tailpipe emissions of hybrids contain less pollution than the air.

A 2008 study by researchers at Carnegie Mellon University found that America’s electricity mix derives 45 percent of electricity from coal, 23 percent from natural gas, 20 percent from nuclear, and 12 percent from dams, solar, wind and other sources. The emissions associated with electric and hybrid vehicles will improve significantly once we reduce the use of fossil fuel powered energy, particularly coal.

One of the most interesting findings of the Carnegie research finds that even when electricity derived from coal is used to power hybrids they emit fewer greenhouse gases than gasoline-powered cars.

In states with cleaner power mixes, plug-in hybrids have less than half the greenhouse gas footprint of conventional gasoline vehicles.

In a recent study, Mark Jacobsen, a professor of civil and environmental engineering found that electric vehicles powered by wind energy were best, with a 99 percent reduction in carbon and air pollution emissions from the current vehicle fleet. Not suprisingly, ethanol ranked last in his study, with the largest carbon footprint.

“There’s no technical reason we can’t ramp up to a lot more electric vehicles,” Jacobsen said. “It’s a question of whether society as a whole is motivated to do it.”

Andy Carroll, Managing director for Eurotax Glass’s, said the key to making electric vehicles more popular will be for manufacturers to completely remove the risk of residual value in batteries from falling into the hands of the customer.