Why Autonomous Cars Could be Bad for the Environment—or Maybe Not

A new study finds that autonomous vehicles could harm the environment, but experts are pushing back on the claim. 

The MIT report says the energy needed in the future to run the computers required for autonomous vehicles could generate as much greenhouse gas emissions as today's data centers. Nonsense, says Raj Rajkumar, Director of the Metro21 Smart Cities Institute and Professor of Electrical & Computer Engineering at Carnegie Mellon's College of Engineering, and a pioneer in autonomous vehicle technology.

"First and foremost, in the timeframes being considered by the study, many of these autonomous vehicles will be EVs, i.e., zero-emission vehicles," Rajkumar told Lifewire in an email interview. "When AV electronics (sensors, computations, and communications components) consume energy, that reduces the number of miles that can be driven per charge, but the amount of emissions is still zero per vehicle."

Big Data Footprint

The MIT researchers found that 1 billion autonomous vehicles, each driving for one hour per day with a computer consuming 840 watts, would consume enough energy to generate about the same amount of emissions as data centers currently do. Also, to keep autonomous vehicle emissions from exceeding current data center emissions, each vehicle must use less than 1.2 kilowatts of power for computing, which would require more efficient hardware.

"If we just keep the business-as-usual trends in decarbonization and the current rate of hardware efficiency improvements, it doesn't seem like it is going to be enough to constrain the emissions from computing onboard autonomous vehicles," Soumya Sudhakar, a graduate student in aeronautics and astronautics and one of the paper's authors, said in the news release. "This has the potential to become an enormous problem. But if we get ahead of it, we could design more efficient autonomous vehicles that have a smaller carbon footprint from the start."

Marc Bolitho, CEO of Recogni, a company that makes systems that can be used in autonomous vehicles, said the primary environmental concern is around the range because of the motor, the vehicle's weight, and the passengers' weight or the freight in the car. Even wiring harnesses can weigh up to 200 pounds, he said.

"But if the computing power of autonomous systems consumes a significant chunk of that, then it has implications on what's called advertised range, what the vehicle manufacturer can advertise as range because then otherwise, they have to the fine print and caveat everything (i.e., this range is achievable only if you don't turn on the air conditioner, don't turn on the stereo or radio, don't turn on the other systems that require computing power, etc.)," he added. 

Rajkumar said there are valid questions to ask about the resource-intensive processes needed for manufacturing batteries and their impact on planetary resources, emissions, and geopolitics. 

"But those questions pertain to the much larger energy consumption of making EVs and their batteries," he added. "The resource consumption of AV components is by definition a subset of that much bigger number and are relatively small."

The study compares energy consumption in millions of individual vehicles against the concentrated energy consumption in a small number of data centers, Rajkumar pointed out. "Individual vehicles can be powered by 'zero-emission' batteries on the vehicle itself, but the prodigious amount of energy consumed by data centers has to come from the grid," he added. "Energy production in the grid, of course, can come from highly polluting sources like coal plants."

EVs’ Dirty Secret

Tech analyst Bob Bilbruck, the CEO of Captjur, told Lifewire via email that it's not just autonomous vehicles that are polluters. Electric cars, some of which, like Tesla models, have semi-autonomous driving systems, are the "dirty little secret" of the green movement, he said. 

"Stars drive around in them so they and their publicists can look good, but driving an EV could actually be doing more damage to the environment than, say, a fossil fuel vehicle," he added. "You still have to produce the power for the electric grid to power these vehicles, and that power is coming from many non-green sources, not to mention these vehicles take an ample supply of rare earth materials to build these vehicles and the expanded rare earth mining is ruining the environment more than fossil fuel extraction."