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A Roadmap to Climate-Friendly Cars

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An electric car is only as good for the climate as the electricity used to power it. And in states that rely heavily on fossil fuels like coal and natural gas for their electricity there are many conventional and plug-in hybrid electric vehicles that are better for the climate than all-electric cars today.

But that is just part of the story. Another critical factor is the carbon emissions generated when a car is manufactured. Emissions from producing the battery and other electrical components create a 10,000 to 40,000-pound carbon debt for electric cars that can only be overcome after tens, or even hundreds of thousands of miles of driving and recharging from clean energy sources.

MORE: You Asked, We Answered: Response to 2013 Cars Report

This comprehensive state-by-state analysis of the climate impacts of the electric car, plug-in hybrid electrics, and high-mileage, gas-powered hybrid cars takes both of these factors into account – the source of energy used to power the car and carbon emissions from vehicle manufacturing.

We found:

• In 40 states, a high-efficiency, conventional gas-powered hybrid, like the Toyota Prius, is better for the climate (produces fewer total “lifecycle” carbon emissions) than the least-polluting, all-electric vehicle, the Honda Fit, over the first 50,000 miles the car is driven.

• In 26 states, an efficient plug-in hybrid is the most climate-friendly option (narrowly outperforming all-electrics in 10 states, assuming a 50:50 split between driving on gas and electric for the plug-in hybrid), and in the other 24 states, a gas-powered car is the best. All-electrics and plug-in hybrids are best in states with green electrical grids with substantial amounts of hydro, nuclear and wind power that produce essentially no carbon emissions. Conventional hybrids are best in states where electricity comes primarily from coal and natural gas.

• For luxury sedans, in 46 states, the gas-powered Lexus ES hybrid is better for the climate than the electric Tesla Model S, over the first 100,000 miles the car is driven.

Greener Grid Needed to Reap Benefits of Electric Cars

In just two years, from 2010 to 2012, a greener grid from more natural gas and wind-generated electricity led to an 8 percent reduction in carbon emissions per kilowatt-hour generated nationally. Combined with more efficient electric cars:

• This reduction in carbon emissions from electric power generation more than doubled the number of states where driving and charging a high-efficiency all-electric vehicle (but not counting any vehicle manufacturing emissions) is better for the climate than a gasoline-powered Toyota Prius hybrid; from 13 in 2010, to 32 states in 2012. (The Prius is the most climate friendly conventional hybrid/gasoline powered vehicle on the market.)

But when all the carbon emissions associated with building and driving electric and high-mileage gasoline cars are included in the analysis, the all-electric advantage goes up in smoke. In the vast majority of states, the significant carbon debt associated with the production of electric car batteries outweighs recent reductions in carbon emissions from power generation and efficiency improvements of some electric vehicles.

State By State Summary

Swing states. In many states the rapid substitution of coal with natural gas and the adoption of substantial amounts of wind power have measurably decarbonized the grid from 2010 to 2012.These changes have shifted the balance of carbon emissions in favor of recharging electrics vs. burning gasoline in high-mileage hybrids like the Prius, if car manufacturing emissions are excluded.

Click image to enlarge.

In Pennsylvania, Virginia, and Alabama, the share of electricity generated with natural gas increased by about 10 percentage points while coal’s share dropped an equivalent amount. In Texas, natural gas generated electricity is up about 5 percentage points, with coal down the same, and wind now accounts for 9 percent of the state’s power. In Iowa, coal use dropped 10 percentage points and wind power jumped 8 percentage points, while in Nevada coal fell 10 percentage points, natural gas was up 5 percentage points and solar was up 3 percentage points.

In all these states, a relatively modest shift to less carbon intensive electricity generation — generally around a 10 percent shift from coal to gas or an equivalent increase in the percentage of wind or solar — pushed all-electric vehicles ahead of conventional hybrids in terms of climate benefits associated with driving and recharging (but not including manufacturing emissions).

But when manufacturing emissions are included, gas-powered hybrids, or plug-in hybrids, which run on mix of gas and electricity, are the most climate-friendly choice.

Dirty Energy States. Eighteen states, including Colorado, Missouri, New Mexico, Michigan, and Ohio, still heavily depend on coal, or have virtually no renewables and little nuclear power in their electricity mixes. Driving and recharging an electric car in these states is worse for the climate than burning gasoline in a conventional hybrid or high-mileage car. Including manufacturing emissions in the calculations makes the electric car even less climate friendly.

Climate-Friendly Electricity States. In 10 states (Washington, Oregon, Connecticut, Idaho,Vermont, New York, New Jersey, New Hampshire, South Carolina, and South Dakota), the best electrics are better for the climate than any gasoline car even when manufacturing emissions are included. Washington, Oregon, Idaho and Vermont have the cleanest grids, producing few carbon emissions, primarily through reliance on hydropower, nuclear, and small percentages of wind and solar. In these states, the mpg equivalents of the best electric vehicle are dazzling, ranging from more than 2,600 mpg in Vermont, to 380 mpg in Washington, 280 mpg in Idaho, and 200 mpg in Oregon.

Full List of Cars at 50,000 miles

Full List of Cars at 100,000 miles

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