Are electric cars really better for the environment?

Are electric cars really better for the environment?

This story is part of Plugged in, CNET’s hub for all things EV and the future of electric mobility. From vehicle reviews to helpful tips and the latest industry news, we’ve got you covered.

While most players in the auto industry are tripping over themselves to bring electric and electric cars to market as soon as possible, a large portion of consumers are skeptical about the impending EV revolution. That has led to a long list of myths and half-truths about battery-powered driving, myths that we would like to tackle right away.

We’re going to tackle those myths and we’ll start with perhaps the most ubiquitous out there. Many believe that electric cars are actually worse for the environment than traditional gasoline-powered cars. Today we dive deep, look at all the numbers and determine how much truth there is in that statement.

At first glance, it seems ridiculous — the idea that a battery-powered car that runs completely zero-emissions could have a more negative impact on the environment than a car that constantly pumps carbon dioxide and other pollutants into the environment. But the truth, of course, goes much deeper than that.

While that EV might run clean as it carries you on your commute, the electricity that powers it has to come from somewhere. Critics say that’s the crux of the problem. Many parts of the world still get the vast majority of their electricity from sources such as coal or natural gas, resulting in significant CO2 emissions. Do the math, say those critics, and you’ll see that electric cars are no better than a car with an internal combustion engine.

WHERE? Before we get into the numbers, let me set some ground rules. First, all the math here is based on driving in the good old USA of A. Why? We are fortunate to be able to draw on a wealth of information and calculators collected by the Environmental Protection Agency to determine the environmental impact of what we drive. That doesn’t mean our findings here don’t apply elsewhere in the world, but you may have to skew the numbers one way or another, depending on the mix of renewables in your region for power generation.

Secondly, I am only going to talk about CO2 emissions here. Not only is CO2 the most significant contributor to climate change, but it is also the most direct way to compare the environmental impact of an EV to an ICE car.

2022 BMW M340i xDrive

To be honest, that purple is worth the extra CO2.

Craig Cole/Roadshow

Which cars specifically? On the EV side, the decision is easy: Tesla’s Model 3† It is the most popular (or at least the best-selling) EV in the world. On the gas-powered side, finding a direct comparison can be a bit tricky, but I decided to go with the BMW M340i xDrive† It’s priced comparable to the Tesla, has about the same horsepower (382 horsepower to be exact), and has four-wheel drive to boot.

On to the math. Even within the continental US, where you live, this has a huge impact on your overall emissions. I wanted to do the worst-case scenario calculation for the EV and to do that I had to pick the place with the dirtiest power generation possible. According to the EPA, that’s part of the grid called the Midwest Reliability Organization East, an area in the central part of the continental US that gets just 14% of its power from renewable sources. So, for these calculations, pretend you live in Green Bay, Wisconsin.

And what does that look like? In addition to being unreasonably cold in the winter and exceptionally cheesy year-round, a Tesla Model 3 in Wisconsin generates 210 grams of CO2 per mile driven. That includes all emissions, not just from the generation of the power that moves the car, but also the overhead and losses associated with carrying that power across our somewhat outdated grid.

The BMW? Where you drive a car that runs on gas, it does not have much of an impact on emissions. BMW says the M340i xDrive puts out 168 grams of carbon per kilometer, and since there are 1.6 of those per mile, that gives us 269 grams of carbon per mile. That’s significantly higher than the Tesla, even charging on the dirtiest power in the US. Case closed? Not quite yet.

Porsche E-fuelPorsche E-fuel

It’s not just about what your car burns, but also where it comes from.


According to the Ministry of Energy, for every four gallons of gas you burn in the US, an extra gallon was burned carrying that gasoline to the pump. So, to be fair, we really need to increase BMW’s CO2 emissions by another 25%. That costs us up to 336 grams of CO2 per mile, or about 50% higher than the Tesla.

But don’t start beaming, EV fans, because we’re still not done. To be complete, we need to calculate the environmental impact of making the battery pack in that Tesla. Unfortunately, we cannot do that with 100% certainty. Why? Because Tesla does not release figures about this and we are therefore forced to engage other experts. I read dozens and dozens of studies that attempted to reverse engineer the environmental impact of Tesla battery manufacturing, but most of them missed a crucial aspect, like ignoring the impact of mining the raw materials.

The most comprehensive photo I could find came from a survey by Circular energy storageitself based on data from the Argonne National Lab (PDF), which publishes absolutely exhaustive figures and data on the environmental impact of all types of driving. That data estimates that 7,300 kg of CO2 is generated for the creation of a 100 kilowatt-hour Tesla battery pack. Because the Model 3 has a battery pack of about 75 kWh, we can reduce that figure to 5,500 kg of CO2.

That means the Tesla has to overcome a significant handicap before it even rolls off the dealership. But based on the above figures per mile, we can calculate how long it would take to make up for that. The answer? 47,413 miles, or just over three years of average driving for the average American. After that, the Tesla Model 3 has made up for it and will forever be cleaner than the BMW.

Tesla Alaska Test FacilityTesla Alaska Test Facility

Believe it or not, driving like this in Alaska is actually better for the environment.

Nick Miotke/Roadshow

But remember, that’s the worst-case scenario. If instead you drive your EV to Alaska, which has the highest rate of renewable energy use in the continental US, the Model 3 produces a whopping 130 grams of CO2 per mile. That brings the breakeven point to 26,699 miles, or about two years of average driving.

So there you have it. Even when using electricity largely from coal, and even taking into account the build-up of the battery pack, EVs have a significantly smaller impact on the environment than traditional petrol-powered cars.

What happens if those batteries can’t hold a charge? And how long does that actually take? And how much money can you save with an electric car instead of burning gasoline? For all those answers and more, stay tuned for the next installment of EV’s Exposed!