LIZZIE WADE SCIENCE DATE OF PUBLICATION: 03.31.16.
TESLA’S ELECTRIC CARS AREN’T AS GREEN AS YOU MIGHT THINK
ELON MUSK IS unveiling the Tesla Model 3 today. If you’re planning to buy one, you’re probably feeling pretty good about yourself. Not only will you have a sweet ride, but you’ll be doing something good for the environment! No gasoline-powered sports cars to get you through your midlife crisis, thank you very much. You care about global warming.
But how green is a Tesla, really? Devonshire Research Group, an investment firm that specializes in valuing tech companies, dug into the data and concluded that Tesla’s environmental benefits may be more hyped than warranted. Devonshire isn’t saying that Tesla is pulling a Volkswagen, or that its cars are spewing greenhouse gases from invisible tailpipes. It’s arguing that Teslas (and, by extension, all electric vehicles) create pollution and carbon emissions in other ways. Each stage of an EV’s life has environmental impacts, and while they aren’t as obvious as a tailpipe pumping out fumes, that doesn’t make them any less damaging.
Let’s start with the basics. Your electric car doesn’t need gas, but it still might get its energy from burning carbon. It depends on how your local grid generates electricity. “If you use coal-fired power plants to produce the electricity, then all-electrics don’t even look that much better than a traditional vehicle in terms of greenhouse gases,” says Virginia McConnell, an economist at the environmental research firm Resources for the Future. But if your local grid incorporates a fair amount of renewable solar and wind energy, like California, your electric vehicle is pretty clean.
Of course, gasoline doesn’t exist in a vacuum, either: Refining, processing, and transporting gas add emissions that car owners must factor into their overall carbon footprint, the so-called “well-to-wheel” tally. It takes as much energy to produce a gallon of gasoline as a Model S consumes in 20 miles of driving, according to Department of Energy data. When you add all those extra expenditures up, “an electric car like the Model S has almost four times lower CO2 per mile than an equivalent gas-powered car,” says a Tesla spokesperson. So while the emissions argument is tantalizing for gas guzzlers, the average numbers still come out in favor of electric vehicles.
The math gets trickier, though, when you include other forms of environmental damage. Electric cars need to be light, which means they include a lot of high-performing metals. The lithium in the batteries, for example, is super light and conductive—that’s how you get a lot of energy without adding a lot of weight. Other, rare metals are sprinkled throughout the car, mostly in the magnets that are in everything from the headlights to the on-board electronics.
But those rare metals come from somewhere—often, from environmentally destructive mines. It’s not just Tesla, of course. All electric vehicles rely on parts with similar environmental issues. Even solar panels depend on rare metals that have to be dug out of the earth and processed in less-than-green ways, says David Abraham, author of the book The Elements of Power. (Disclosure: I helped edit some chapters of the book.)
We can’t look at mining as an over-there thing and at Tesla as an over-here thing. They’re intricately linked.
Rare metals only exist in tiny quantities and inconvenient places—so you have to move a lot of earth to get just a little bit. In the Jiangxi rare earth mine in China, Abraham writes, workers dig eight-foot holes and pour ammonium sulfate into them to dissolve the sandy clay. Then they haul out bags of muck and pass it through several acid baths; what’s left is baked in a kiln, leaving behind the rare earths required by everything from our phones to our Teslas.
At this mine, those rare earths amounted to 0.2 percent of what gets pulled out of the ground. The other 99.8 percent—now contaminated with toxic chemicals—is dumped back into the environment. That damage is difficult to quantify, just like the impact of oil drilling.
And, as in every stage of the process, mining has hidden emissions. Jiangxi has it relatively easy because it’s digging up clay, but many mines rely on rock-crushing equipment with astronomical energy bills, as well as coal-fired furnaces for the final baking stages. Those spew a lot of carbon dioxide in the atmosphere in the process of refining a material destined for your zero-emissions car. In fact, manufacturing an electric vehicle generates more carbon emissions than building a conventional car, mostly because of its battery, the Union of Concerned Scientists has found.
“We’re shifting pollution, and in the process we’re hoping that it doesn’t have the environmental impact,” says Abraham. He believes that when you add all the environmental impacts, they still come out in favor of electric vehicles. (The Union of Concerned Scientists agrees; it found that even when you add in emissions from battery manufacturing, EVs generate half the emissions of a conventional car over the course of its life.) Still, consumers and investors should understand what it takes to make the materials that enable their green choices. “I don’t think there’s been much discussion of that,” Abraham says. “We can’t look at mining as an over-there thing and at Tesla as an over-here thing. They’re intricately linked.”
Overall, “the greenhouse-gas-emissions footprint of electric vehicles can be pretty high on the front end, as they’re being built,” says McConnell. “And so you need to get a lot of benefits on the other side, when you use it.” And after you’re done using it.