If you’ve ever gotten into a heated discussion about electric cars, there’s likely been someone in the group who wasn’t convinced that they’re any cleaner than the gasoline-powered cars prevalent on US roads today. “Yeah, well they use electricity and most electricity comes from coal,” they’ll say, before, perhaps, diving into an off-the-cuff analysis of the environmental cost of building and disposing of the big lithium-ion batteries that make EVs go. So what’s the answer? In general, says the Union of Concerned Scientists (UCS), EVs emit fewer greenhouse gas pollutants throughout their lifecycle than comparable internal combustion engine (ICE)-powered cars. But the story behind those numbers is more complicated.
Not surprisingly, EV emissions vary by vehicle – depending upon a number of factors, including the vehicle’s size and where it will be used. Battery-powered cars aren’t as effective at reducing GHG emissions when they’re using coal-fired electricity to recharge. Most EVs, however, are sold in places where they tend to make the most sense – in other words where wind, solar, hydroelectric and other renewable energy sources are a bigger part of the electrical grid. EVs have a lower impact in places like Oklahoma, Kansas or Missouri – where they match ICE cars that get 53-67 mpg – than they do in the far West, where the equivalent can be as high as 147 mpg.
UCS says that on average, EVs’ GHG emissions are equivalent to a gasoline-powered car that gets 80 mpg. Even the most fuel efficient non-plug-in gas-electric hybrid on the market – the 2019 Honda Insight – has an EPA combined fuel economy rating of only 52 mpg. According to the EPA, the average fuel economy for new cars is currently a hair under 25 mpg.
Then there’s the size factor. Obviously, a heavier vehicle will use more juice, whether it’s run on gasoline or electricity. But emissions created during manufacturing is the real kicker – UCS says heavier EVs, like one with a 265-mile range, will have 68 percent more manufacturing emissions than their ICE counterparts, although overall emissions will be 53 percent lower throughout the life of the EV. Here’s what UCS had to say about it in its 2015 report:
“With gasoline cars, we have found that vehicle operation accounts for almost 90 percent of the lifetime global warming emissions, making the manufacturing emissions a smaller portion of the life cycle burden. By contrast, BEVs produce lower emissions during operation, with emissions from manufacturing being a more significant contributor to the total life cycle emissions.”
Since that report was published, EV production has grown by leaps and bounds, even if they are still a small percentage of the market. If you compare this year’s crop of EVs with what was on the market even a couple of years ago, battery technology has improved, resulting in more EVs with a range over 100 miles. Remember those stories about people barely making it where they were going in a Nissan Leaf with an 84-mile range? The Leaf now comes standard with a 40 kWh battery and a 151-mile range, or an optional 62 kWh battery with a 226-mile range. There are other comparable models on the market, as well as some better ones. There’s now even an all-electric Jaguar, the I Pace.
According to the Energy Information Administration, there were still 219 coal-fired power plants online in the US as of 2017. Sam Abuelsamid, a mobility analyst at Navigant Research, says coal plants have been on the decline for years, a trend that’s likely to continue.
“When you factor in the average mix of electricity in the US, the lifetime emissions of EVs are cut in half compared to fossil fuel-powered vehicles,” he said. “As the mix goes further away from coal that only gets better.”
Disposal is the big question mark in the whole lifecycle equation. We all know where our gasoline-powered cars go when they’re all used up – to the metal recycler. Abuelsamid says there are some companies working on battery recycling technology, but there isn’t enough data available yet spell out used batteries’ impact. But there are also lingering questions about the carbon emissions created by the extraction of coal, oil and battery production materials. Again, not enough data.
The bottom line is that even if you used 100 percent coal to power an EV – not a likely scenario anymore – its emissions would be only slightly worse than those produced by a very efficient gasoline-powered car.