Electric cars: Big climate aid in L.A., but not Wichita

Apparently, location, location, location is the latest twist on electric vehicles and the environment: Whether an electric car such as the Nissan Leaf protects the atmosphere from greenhouse gases depends on where it's charged, according to a new study. Such a car is no better than a standard gasoline-powered subcompact such as a Hyundai Elantra in cities such as Denver and Wichita, but far exceeds even the best hybrids in Southern California.

That's the findings of a study of electricity generation, greenhouse gas emissions and electric vehicles by the Union of Concerned Scientists.  The variations in how beneficial an electric vehicle is for reducing pollution that causes global warming result from regional differences in how electricity is generated.  

The scientific organization, which is a vocal proponent for federal requirements mandating increased fuel efficiency in vehicles, said in regions covering 45 percent of the nation's population, "electricity is generated with a larger share of cleaner energy resources _ such as renewables and natural gas _ meaning that EVs produce lower global warming emissions than even the most efficient gasoline hybrids."

But in regions where coal still makes up a large percentage of the electricity grid mix, the most efficient gasoline-powered hybrid vehicles will yield lower global warming emissions than an electric vehicle.

However, electric vehicles tend to reduce oil consumption in nearly all regions, the group said.

The Union of Concerned Scientists also said that electric vehicle drivers can save $750 to $1,200 a year compared with operating an average new compact gasoline vehicle with a fuel economy rating of 27 miles per gallon that is fueled with gasoline at $3.50 per gallon.

The savings depend on how much a local utility charges for electricity and that varies widely between regions.  Regardless of location, that range of savings requires charging on the lowest-cost electricity plan and that may require a switch from their current rate plan to the most advantageous one - often limiting time of use to night hours_offered by their utility. The group noted that that was especially important in California.

"It pays for California EV owners to learn about the different kinds of rate plans their local utility has to offer when plugging in their vehicle at home. They may be leaving hundreds of dollars per year in savings on the table." said Don Anair, the report's author and senior engineer for UCS's Clean Vehicles Program.

When it comes to pollution, charging an EV in the cleanest electricity regions, which include California, New York (excluding Long Island), the Pacific Northwest and parts of Alaska, yields global warming emissions equivalent to a gasoline-powered vehicle achieving over 70 mpg.

The group said about 37 percent of Americans live in regions where an electric vehicle has the equivalent global warming emissions of a 41 to 50 mpg gasoline vehicle, similar to the best gasoline hybrids available today. For example, charging an EV in Florida and across most of Texas yields global warming emissions equivalent to a 46 to 47 mpg gasoline vehicle; this is the fuel economy level of vehicles such as the Honda Civic Hybrid (44 mpg) and Toyota Prius Hybrid (50 mpg).

But the group said 18 percent of Americans live in regions where an electric vehicle has the equivalent global warming emissions of a 31 to 40 mpg gasoline vehicle, making some gasoline hybrid vehicles a better choice with respect to global warming emissions.

"The Rocky Mountain grid region (covering Colorado and parts of neighboring states) has the highest emissions intensity of any regional grid in the United States, which means an EV will produce global warming emissions equivalent to a gasoline vehicle achieving about 33 mpg. Gasoline- powered cars with fuel economy at this level include the Hyundai Elantra (33 mpg) and the Ford Fiesta (34 mpg)," the group found.