Computers that power self-driving cars could become a driver of global carbon emissions

In the future, self-driving cars' computational needs may fuel a large increase in global carbon emissions. The energy needed to run the powerful computers onboard a global fleet of autonomous vehicles could generate as much greenhouse gas emissions as what all global data centers combined currently emit.

That’s one key finding of a new study by researchers at the Massachusetts Institute of Technology that explored the potential energy consumption and related carbon emissions of autonomous vehicles if they are widely adopted. The research was funded in part by grants from the U.S. National Science Foundation and is published in IEEE Micro.

The data centers that house the physical computing infrastructure used for running applications are widely known for their large carbon footprint. They account for about 0.3% of global greenhouse gas emissions, or about as much carbon as the country of Argentina produces annually, according to the International Energy Agency.

Realizing that less attention has been paid to the potential greenhouse gas footprint of autonomous vehicles, the MIT researchers built a statistical model to investigate the problem. They determined 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 level of emissions as all global data centers currently do.

"If we just keep 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," says first author Soumya Sudhakar, who co-wrote the paper with Vivienne Sze and Sertac Karaman.

"These vehicles could actually be using a ton of computer power,” Karaman says. “They have a 360-degree view of the world, so while we have two eyes, they may have 20 eyes, looking all over the place and trying to understand all the things that are happening at the same time.”

While there are still many scenarios to explore, the researchers hope that this work sheds light on a potential problem people may not have considered.

"We are hoping that people will think of emissions and carbon efficiency as important metrics to consider in their designs,” says Sze. “The energy consumption of an autonomous vehicle is critical, not just for extending battery life, but for sustainability.”

Adds Alex Jones, a program director in NSF’s Division of Computer and Network Systems, "The sustainability challenge for new computational and connected technologies such as autonomous vehicles is an important motivator for the new Design for Environmental Sustainability of Computing Program at NSF. The program encourages thinking differently about computing's sustainability to be transformative in reducing environmental impacts of future information and communication technologies."