Are EVs worth it? Study helps calculate savings on emissions, fuel.

How much an EV saves on fuel or cuts greenhouse gas emissions depends on many variables, including gas prices and whether the local electric grid is fed mainly by coal power. The Union of Concerned Scientists helps out with the calculations.

Compared with most cars, electric-drive vehicles are a plus for the environment – no matter where in the US they charge up. Their lower fuel costs, moreover, make them increasingly competitive with many conventional high-mileage vehicles and hybrids, a new study finds.

Even in states where coal-burning power plants predominate on the electric grid, an electric-drive vehicle accounts for fewer emissions than does a conventional vehicle, according to the Union of Concerned Scientists study. Only the most efficient hybrid cars outperform electric-drive vehicles (EVs) on emissions in those states where coal is a major contributor to the electricity used for recharging EV batteries. 

Electric-drive vehicles (EVs) also compare well on fuel costs, saving their owners as much as $1,200 a year over the average new conventional internal combustion compact car that gets 27 miles per gallon (assuming the price of gasoline is $3.50 a gallon). The report makes it possible for consumers to do detailed comparisons, breaking down fuel costs across 50 cities and emissions across all 50 states.

Those findings could help consumers sort through all the electric-drive plug-in vehicles pouring onto the US vehicle market – to the tune of a dozen this year.

“Those in the market for a new car may have been uncertain how the global warming emissions and fuel costs of EVs stack up to gasoline-powered vehicles," Don Anair, a senior engineer for UCS’s Clean Vehicles Program, said in a statement. "Now, drivers can for the first time see just how much driving an electric vehicle in their hometown will lower global warming emissions and save them money on fuel costs.”

Regional disparities in electric grid emissions, gasoline prices, and the cost of electricity make comparisons tough. The UCS analysis takes into account the sources of local electric power and then breaks the United States into "good," "better," or "best" emissions categories.

Forty-five percent of Americans live in "best" regions, where an EV has lower greenhouse gas emissions than a gasoline-powered vehicle that gets 50 m.p.g., surpassing even the best electric-gasoline hybrids on the market. In California and most of New York, meanwhile, an EV’s environmental performance could equal the performance of an 80-m.p.g. gasoline-powered vehicle, if there is such a beast.

An EV owner in Boston would see major emissions savings and a fuel cost savings of about $850 a year, compared with a 27-m.p.g. conventional vehicle. An EV owner Oklahoma City, where electricity prices are lower, would save $1,150 a year. But emissions improvement for the Oklahoma EV owner would be only about half that of the New England EV driver because of the region's larger reliance on coal power. 

EVs cost more upfront, but they also are a buffer against rising gasoline prices. For each 50-cent increase in gas prices, an EV driver can expect save an extra $200 a year, the study says.

Today an EV driver could use 6,100 fewer gallons of gasoline and save nearly $13,000 on fuel over the life of the vehicle compared with the average new compact car. Savings are less dramatic, however, when EVs are compared with high-mileage standard hybrids or high-mileage conventional vehicles.

That means consumers will still have some of their own calculating to do. Will the EV's substantial fuel savings be enough to cover their higher sticker prices? The Nissan Leaf, an all-electric car, costs about $32,000, and the Chevrolet Volt plug-in hybrid vehicle, which has a big electric motor and small gasoline range extending engine, costs about $39,000, according to Edmunds.com. Would that $13,000 fuel savings make up for the higher cost of a Leaf or Volt?

Charging an EV in Florida and across most of Texas yields global warming emissions equivalent to a 46- to 47-m.p.g. gasoline vehicle – about the same fuel economy level as vehicles like the Honda Civic Hybrid (44 m.p.g.) and Toyota Prius Hybrid (50 m.p.g.). Those two vehicles cost about $24,000 and $23,000, respectively, says Edmunds.com. Even if fuel savings on the Leaf or Volt beats those hybrid vehicles in the long run, how the math works out in the end depends on how long an owner keeps the EV. 

In short, there's no one-size-fits-all answer when assessing whether an EV is worth it. But the UCS findings provide useful rules of thumb and a basis for knowing if an electric vehicle makes environmental and cost sense where you live, its experts say.

“This report shows drivers should feel confident that owning an electric vehicle is a good choice for reducing global warming pollution, cutting fuel costs, and slashing oil consumption,” Mr. Anair said.