(CBS) - When you think of "going green" with a car purchase do you think first of an all-electric car? New research indicates they're not always the greenest choice for the long haul.
"There's actually two ports - there's one for the charging."
Hector Ybanes says when customers come in to look at the all-electric Nissan Leaf at the Fremont Auto Mall, the environment is often at the top of their minds.
"And you are doing both. You are saving money and you're saving the environment.
and pretty much help the whole world start this movement and everybody go green," say Ybanes.
The base price is $29,000, the Leaf gets the equivalent of 129-miles-per-gallon, and even has a solar panel on the roof to help charge the battery system. Everybody is impressed, everybody is happy. But a new study by the research group Climate Central says all electric vehicles are not always the "greenest" choice. Depending on which state you live in - and the environmental impacts of the power generated in those states - in some cases a gas-electric hybrid is actually the more environmentally friendly choice.
"What it comes down to is the source of the electricity."
Alyson Kenward is a senior scientist at climate central…and is one of the study's main authors.
"So just because electric cars don't run on gasoline and they don't have a tailpipe doesn't mean they are zero emission. You have to think about the emissions that come from the electricity that goes into charging those vehicles so you can drive them."
All vehicles also have what researchers call a carbon debt from the manufacturing process at the time they roll off the showroom floor. So factoring in that initial carbon debt -- and the ongoing source of power from the electric grid --researchers have put it all together to analyze the long term environmental impact. so in states that have really clean forms of electricity or low emissions forms of electricity - like hydro power, nuclear power - in places like that then electric cars are really a more climate-friendly option than the best gas-powered cars.
So the cleanest cars after driving 100 thousand miles in California for example, include the Toyota Prius plug-in hybrid, the electric Honda Fit and the electric Nissan Leaf.