America’s high-carbon electricity grid is short-circuiting efforts to give consumers climate-friendly, electric vehicle (EV) options. Depending on where you live, generating the electricity to charge an electric car can produce more greenhouse gas (GHG) pollution than driving a fuel-efficient, gasoline-powered car.
EVs are much better for the climate than the average-mileage vehicle in the U.S, but in 36 states, the hybrid electric Toyota Prius produces less GHG pollution than the all-electric Nissan Leaf. When you plug in a Leaf to recharge, you tap into electricity generated largely by burning coal and natural gas in those states, according to a Climate Central report, “A Roadmap to Climate-Friendly Cars.”
“The good news is that Americans have lots of choices to reduce the carbon footprint from their daily driving,” said Eric Larson, who is on the research faculty at Princeton University and is a senior scientist at Climate Central, where he was the lead author of the report. “In many states, popular high-mileage hybrid and conventional gas-powered cars are excellent climate-friendly alternatives to electric cars.”
The report provides a state-by-state road map to the most climate-friendly cars on the market. The analysis compares life cycle emissions associated with the Nissan Leaf and Chevrolet Volt, the top-selling all-electric and plug-in EVs, with hybrids such as the Prius and other high-mileage, conventional gas-powered cars. (Hybrid EVs such as the Prius can be thought of simply as high-efficiency gasoline cars because they derive all of their power from gasoline; their batteries are recharged by running the engine and recovering braking energy.)
In the 10 states with the most carbon-polluting electricity generation, there are 20 cars that are better for the climate than the Leaf. Thirteen of them are gas-powered vehicles with conventional engines. The rest are gas-powered hybrids.
The partially electric Volt has a similar profile, depending on how often a driver engages its gasoline engine. A Volt, like the Leaf, plugs in to charge its battery, but when the charge is depleted during driving it switches to its onboard gasoline engine to keep going. If a Volt drives half its miles using gasoline and half using electricity from plug-in charging of its battery, it is a bigger carbon polluter than the Prius in 45 states.
Coal is the largest contributor to the high-carbon footprint of the electrical grid. In states such as Wyoming or Indiana, where 90 percent or more of the electricity comes from coal, driving a Leaf is responsible for much more GHG emissions per mile (about 0.9 pounds) than a Prius (about 0.5 pounds). The Leaf fares better in states that get a significant share of their electricity from natural gas, such as Rhode Island or Nevada (about 0.6 pounds per mile), but typically still produces more emissions than a Prius.
The Leaf does best in states that rely heavily on nuclear, such as Connecticut (0.3 pounds), or on hydro power, such as Idaho or Washington (0.1 pounds).
“Our findings don’t mean that we won’t need electric cars as an option for fighting climate change,” Larson said. “In the long term, electric cars may be the cornerstone of personal mobility in a world where carbon emissions are next to zero, which will be required to stabilize the climate.”
But the report highlights the importance of fuel-efficient, gasoline-powered vehicles as a practical, immediate and technologically viable strategy to begin to stabilize the climate.
“This is a technology we understand and that consumers want,” said Alyson Kenward, a Climate Central scientist and co-author of the report. “We expect to see a lot more climate-friendly hybrid, diesel and conventional gas options in the near future as new fuel economy standards are phased in and raise gas mileage to nearly 55 mpg for the average new car by 2025 — about double today’s level.”
Larson said that no matter where someone lives, the Leaf and Volt have better mileage than the average car on the road.
“But until we shift much more of our electricity generation to lower-carbon alternatives, in many states efficient gasoline cars will be the best way to minimize the carbon footprint of daily driving,” Larson said.