When it comes to electric vehicles (EVs), one of the claims that has long been debated is the alleged savings in greenhouse gas emissions.
Think about it: the amount of extra emissions from electric plants obviously offset some of the green benefits, as many power plants around the world still generate electricity by burning coal or other fossil fuels.
And now new research from the University of Tennessee in Knoxville indicates electric vehicles in China may have an overall impact on pollution that is far more harmful than gasoline vehicles.
"An implicit assumption has been that air quality and health impacts are lower for electric vehicles than for conventional vehicles," explained assistant professor Chris Cherry.
"Our findings challenge that by comparing what is emitted by vehicle use to what people are actually exposed to. Prior studies have only examined environmental impacts by comparing emission factors or greenhouse gas emissions."
To reach his conclusion, Cherry analyzed the emissions and environmental health impacts of five vehicle technologies in 34 major Chinese cities, focusing specifically on dangerous fine particles. What Cherry and his team found defies conventional logic: electric cars cause more overall harmful particulate matter pollution than gasoline cars. Particulate matter - generated by the combustion of fossil fuels - includes acids, organic chemicals, metals, and soil or dust particles.
For electric vehicles, combustion emissions occur when electricity to power a car is generated at a plant, rather than when the vehicle itself is actually used. In China, 85 percent of electricity production originates from fossil fuels - and about 90 percent of that is from coal. Researchers discovered that power generated in China to operate electric vehicles emit fine particles at a much higher rate than gasoline vehicles.
This is exactly why some have been arguing the US government shouldn't be pushing electric vehicles so frenetically. Simply put, the new breed of highly efficient gasoline and diesel engines capable of providing fuel economy close to that of hybrids could potentially help reduce overall pollution just as well, if not better, than electric vehicles.
Still, the rate isn't low enough to level the playing field between the vehicles. In terms of air pollution impacts, electric cars are more harmful to public health per kilometer (in China) compared to conventional vehicles. Of course, the study isn't claiming that alll electric vehicles are bad - but does illustrate how we need to be focused on electric vehicles that are powered by electricity plants using clean technology.
"The study emphasizes that electric vehicles are attractive if they are powered by a clean energy source," Cherry concluded. "In China and elsewhere, it is important to focus on deploying electric vehicles in cities with cleaner electricity generation and focusing on improving emissions controls in higher polluting power sectors."