Electric vehicles (EVs) have been a hotbed of innovation and forward thinking for a while now. As EV technology has continued to improve and charging stations have popped up all over the U.S., many have viewed these cars not only as a way to adopt the newest technology, but also become greener. There are more than a few people who haven’t been able to resist the tech of a brand-new Tesla or the ability to reduce carbon emissions with a Nissan Leaf.
But while reducing emissions is a great reason to buy, there are some who have wondered if the technology is as green as everyone thinks it is. Many debate how environmentally friendly EVs are when charging them with electricity generated from non-renewable sources like coal.
Others ask the question, do the emissions produced during the manufacture of the battery and to charge EVs really have less of an environmental impact?
To finally answer these burning questions our Data Science team decided to do the math and get an answer once and for all.
During the manufacturing process, research says that EVs have higher emissions because a battery must be manufactured to power the cars. The Union of Concerned Scientists claim gas cars produce about 7 metric tons or 15,432 lbs. of CO2 emissions during manufacturing, while EVs emissions go up to 8 metric tons or 17,637 lbs. of CO2 emissions. But once electric cars hit the road, they are supposed to make up for that discrepancy. It’s clear that they will if they run on energy generated purely from renewable sources. However, what if the EV is charged from non-renewable energy?
The first step to answering this question is to calculate the average pounds of CO2 emissions per kWh in the U.S. According to EIA’s most recent Electricity Profiles, the generation of each MWh releases 1,009 lbs. of CO2. Thus for each kWh generated, roughly 1 lb. of CO2 is emitted.
Next, it will need to be determined how far an EV can drive per kWh on average. To get this, the average range in miles per charge is determined and divide by the average battery size for EVs. Across all EVs, the average range was 197 miles and the average battery size was 54.65 kWh. Thus, the average miles per kWh is about 3.6.
Therefore, per mile driven, an EV results in 0.27 lbs. CO2. That means if a person drives on average 13,476 miles per year (the U.S. average), this will result in 3,772 lbs. of CO2.
Compared to EVs, gas cars release about 20 lbs. of CO2 per gallon. The most recent analysis showed the average fuel economy across all cars was 24.9 mpg. Therefore, gas-powered cars release about 0.8 lbs. of CO2 per mile driven. If the average person drives 13,476 miles per year, that means, gas cars emit 10,911 lbs. of CO2 compared to 3,772 lbs. emitted by EVs. Put another way, the average EV produces emissions at the same rate as a gas powered car with a fuel economy of 77 mpg. After about 4,160 miles driven, EVs will have made up for additional emissions during the manufacturing process on average.
But by using the national average emissions per kWh to calculate this, it is naturally going to have a large proportion of energy generated by renewable sources, decreasing the average emissions. This is because of states like California, Washington, and Oregon, which produce almost 80% less CO2 emissions than the national average due to the availability of renewable energy production. On the other hand, West Virginia has almost 100% of their electricity generated by coal. The average emissions in West Virginia are 1.949 lbs. of CO2 per kWh generated. Using the calculation above, the average emissions to drive an EV over a year is about 7,286 lbs. of CO2. Though this is almost twice as high as the national average, it is still lower than the emissions from a gas car and will offset the additional emissions during manufacturing after about 8,500 miles of driving.
So, there it is – EVs produce fewer emissions than gas cars regardless of the method of electricity production.
No matter the amount of fossil fuel used to charge the battery, EVs are always more environmentally friendly than gas-powered cars. How much better they are for the environment depends on how the electricity to charge the battery is generated. Even with almost 100% coal-generated electricity, EVs’ CO2 emissions are still over 30% less than gas-powered vehicles before considering the emissions produced transporting and refining gas.
As more renewable sources are used to produce electricity, EVs only stand to become greener. And as EV charging infrastructure continues to expand across North America, and battery technology improves, interested parties are predicting even more flocking to this new driving experience.