Electric and plug-in hybrid cars are often touted as climate friendly because they have no tailpipe emissions (in the case of plug-ins, that applies when driving on the electric charge only). But these alternative-fuel cars are not truly emissions free. In most of the U.S., a portion of the electricity used to charge electric cars is generated by burning fossil fuels. In addition, manufacturing these cars — and their batteries, in particular — is more emissions-intensive than manufacturing traditional cars. So depending on where you live, your most climate-friendly car choice may surprise you.
To help Americans understand their options, we have analyzed the driving and manufacturing emissions of 88 cars, according to which state the cars are driven in. We have also launched our Climate-Friendly Car Guide to let consumers easily search and compare car options based on where they live.
This new report and car guide is an update of our previous report, A Roadmap to Climate-Friendly Cars: 2013. As in the previous report, we’ve based this new analysis on three key components: where you live, what kind of car you drive, and how far you drive. But in this updated report, we’ve included all the model-year 2017 electric, plug-in, and conventional hybrids, and a sampling of the most fuel-efficient, conventional gas-powered cars on the market in the U.S., and we’ve also updated our analysis to reflect recent changes in the power generation mix in each state.
Climate Central’s analysis compares the emissions associated with manufacturing and driving a variety of electric, plug-in hybrid, and gas-powered cars. Three factors influence how climate friendly your car is:
- What you drive: Some cars are more efficient than others at turning energy into miles driven on the road. That’s true for both gas-powered cars and those powered by electricity. Improving a car’s mpg or kilowatt-hours per mile (kWh/mi) rating can have a big effect on its emissions.
- Where you drive: The emissions of electric and plug-in hybrid cars depend on how the electricity they use is generated. The carbon intensity of electricity generation varies from state to state, so powering your car in some states can have a bigger climate impact than in other states.
- How far you drive: Manufacturing cars — electric, gas-powered or otherwise — produces greenhouse gas emissions that are part of the lifetime carbon footprint of a car. But the further a car is driven over its life, the less manufacturing contributes as a fraction of total emissions, because the tailpipe or electric emissions grow with miles driven, while manufacturing emissions are the same no matter how little or how much a car is driven.
What You Drive
In this analysis of climate-friendly cars we have included the growing number of all-electric, plug-in hybrid electric cars, conventional gas-powered hybrids, and conventional fuel efficient gas-powered cars (model year 2017). Our state-by-state rankings are based on the electricity power generation mix for each state in 2015, as reported by the Energy Information Administration (the most recently available data). We have also primarily considered a driving lifetime of 100,000 miles to calculate a car’s total emissions. In addition to tracking the emissions from driving your car (from gas of electricity), we have considered the emissions produced while manufacturing the vehicle.
Compared to our 2013 report, which analyzed model-year 2013 cars, there has been a considerable increase in the number of climate-friendly car options for consumers. Not only are there many more electric, plug-in hybrid, and conventional hybrid model options available on the market, but the U.S. electrical grid has, on average, become greener.
In 37 states, an all-electric car is now the most climate-friendly option, producing fewer emissions for 100,000 miles of driving, compared to the most fuel efficient gas-powered car. In our previous analysis, there were only 13 states where the best electric car that year — a Nissan Leaf — produced fewer emissions when driven 100,000 miles than the Toyota Prius, the most fuel-efficient gas-powered car.
In addition, in 28 states, there are at least five all-electric car models available that are more climate friendly than the greenest gas-powered car, a sign of the increasing variety of all-electric options.
There are also several plug-in electric hybrid options available to American consumers. These cars have driving ranges on battery alone (12 to 50 miles depending on the car) that is extended by their gas-powered engines. Studies indicate that the bigger the battery in a plug-in hybrid, the larger will be the fraction of annual miles its owner drives using the battery rather than the gas engine. In fact, plug-in hybrid cars are more climate friendly than gas-only cars in most states. And in 24 states, at least one-plug-in hybrid car ranks among the top five most climate-friendly choices (see Methodology for more details on the proportion of electric:gas-powered driving for each plug-in model).
There are only 13 states where an exclusively gas-powered car is the lowest emitter for 100,000 miles of driving; in all those states, a conventional hybrid car is the most fuel-efficient, and thus the most climate-friendly, option.
Where You Drive
In addition to the growing number of electric, plug-in hybrid, and gas-powered hybrids available, the continued shift in the U.S. away from coal-fired electricity generation has helped make electric cars a greener choice in many states. Since 2012, 39 states have seen an overall decrease in coal power generation. In most cases, this reduction has been made up by increased generation using natural gas and renewables such as wind and solar power.
Our analysis finds that where electricity generation is not carbon intensive, electric cars are by far the most climate-friendly option. States with little-to-no coal power generation – like California, Idaho, Maine, and Vermont – provide low-emissions grids for electric cars.
In states where electricity generation is still coal heavy – including Kentucky, West Virginia, and Wyoming – fuel efficient gas-powered cars are their lowest-emissions option. In fact, in these states there are more than a dozen gas-powered cars that are more climate friendly than the best electric car. And in these states, plug-in hybrid cars are also usually more climate friendly than all-electric cars.
What’s left are states where coal still contributes to the overall power-generation mix, but a lot comes from other resources, like natural gas, hydro, nuclear, and a blend of renewables. In many of these places, natural gas is the largest source of electricity generation. Although burning natural gas produces fewer emissions than burning coal, it is still an emissions-intensive source of electricity. Despite this drawback, natural gas continues to be stepping stone for many states as they reduce dependence on coal power.
For example, in Florida coal power in 2015 made up only 18 percent of the generation mix, down from 38 percent in 2000. There has been an increase in natural gas electricity generation in the state to meet its power demands, but the overall carbon intensity of Florida’s electrical grid has decreased, making electric and plug-in hybrid cars more climate friendly there than just a few years ago.
Tennessee has seen a similar trend in recent years, where coal power has been reduced by the growing use of natural gas, decreasing the overall carbon intensity of the state’s grid overall. Coal power still comprises 41 percent of the state’s electricity mix, and most of the rest comes from natural gas. Even though an electric car is now the lowest-emissions choice in Tennessee, there are also plug-in hybrid electric cars and a fully gas-powered car within the state's top 10 most climate-friendly cars.
Some states have seen a shift away from coal for renewable technologies, which significantly decreases the carbon intensity of their overall power-generation mix. North Dakota, for example, has replaced about 20 percent of coal power with wind energy since 2000. Yet, with coal power still accounting for 75 percent of the state’s electricity generation, fuel-efficient gas-powered cars are still much more climate friendly for North Dakota drivers than either all-electrics or plug-in hybrids.
How Far You Drive
To fairly judge how climate friendly a car is, you must also consider both how the car is manufactured and how far you drive it over its lifetime — together these comprise the lifecycle emissions of the car. Making the materials that go into a car and then assembling the vehicle itself both take energy use that results in greenhouse gas emissions. Then, fueling the car for driving (either with gasoline or with electricity) also adds to the lifecycle emissions. But, the further you drive the car, the more the fueling emissions add up, while the amount of manufacturing emissions is the same no matter how little or how much a car is driven.
Manufacturing electric vehicles generates more carbon emissions than manufacturing comparable gas-powered cars, with most of the extra emissions due to the manufacturing of the large battery in electric vehicles. However, in states that generate electricity primarily from hydro, nuclear, or renewables — i.e., with low average carbon intensity per kWh generated — charging those electric cars is much less emissions intensive than driving even very fuel efficient gas-powered cars. Over the full lifetime of the car, the lower total manufacturing plus driving emissions for the electric car would make it a more climate-friendly option.
On the other hand, in states that rely heavily on coal and natural gas, the charging emissions for an electric car, combined with the manufacturing emissions, add up to make many gas-powered cars more climate friendly overall.
For our analysis, and for the rankings in our Climate-Friendly Car Guide, we have considered a 100,000-mile lifetime for every car. Though many cars go on to cover more miles, it’s a reasonable mileage benchmark for the owner of any car. However, we have also analyzed vehicle lifecycle emissions over just 50,000 miles. Over this shorter total distance, the manufacturing emissions play a bigger role, and make electric cars less climate friendly than gas-powered cars in many states. On the other hand, over a longer lifetime, the manufacturing emissions play a smaller role.
Considering a 50,000-mile lifecycle, there are only 31 states where an all-electric is the most climate-friendly option for consumers. In the other 19 states, a gas-powered hybrid is the most climate-friendly choice.
The Climate Impacts of the Cars We Drive
In 2015, greenhouse gas emissions from transportation have accounted for nearly one third of all U.S. emissions, and small cars and trucks make up 60 percent of that (passenger vehicles = 42 percent; small trucks, SUVs, minivans = 18 percent). That means driving in the U.S. makes up a large part of its overall climate impact. Shifting the fleet of U.S. cars and trucks to become more fuel efficient and lower emitting would help reduce our country’s overall emissions, and is one of the ways the U.S. can help meet its targets in the Paris Climate Agreement.
Moreover, for most people, the tailpipe emissions from their cars and trucks make up a sizeable portion of their personal carbon footprint — or the total amount of greenhouse gas emissions they are responsible for emitting each year. Choosing a more climate-friendly and low-emissions vehicle is one important way individuals can reduce their carbon footprint, and can help contribute to reducing our country’s total greenhouse gas emissions.
Our Climate-Friendly Car Guide uses a five-leaf rating system to compare vehicle emissions impacts, where a 5-leaf car produces very few emissions and is a very climate-friendly choice. As our new analysis finds, in every state there are many options when it comes to buying a climate-friendly car. There are 38 states that have at least 10 cars that have a four-leaf rating or higher. This means that over 100,000 miles of driving, these cars produce fewer than 31.7 tons of CO2*. There are also 12 states with at least one car achieving a five-leaf rating, meaning those cars produce fewer than 18.4 tons of CO2 over 100,000 miles of driving.
*Car rankings for each state reflect the total emissions over a 100,000-mile lifetime, including emissions during manufacturing. Emissions include both CO2 and non-CO2 greenhouse gases, Throughout this site, we simply use the term CO2 as a shorthand for CO2e.