In a paper published in the journal Frontiers in Energy Research, the researchers propose capturing carbon dioxide from a truck’s exhaust pipe and turning it liquid, which is stored in a tank on the vehicle’s roof. This liquid carbon dioxide can then be delivered to a service station where it can be reused in various ways, including being turned into conventional fuel.

The carbon dioxide capture works by first cooling the gases which are emitted from the exhaust pipe. Special absorbent materials developed at EPFL could separate the carbon dioxide from other gases like nitrogen and oxygen. When it is full, the absorbent material is then heated to extract the carbon dioxide, and heat from the vehicle’s engine is used to compress the carbon dioxide and turn it into liquid. That liquid can then be stored in a box attached to the vehicle’s roof until it can be deposited at a service station when the truck refuels.

The system is more appropriate for large vehicles like trucks or buses than for cars as it is rather bulky, requiring a 2-meter-long capsule and weighing 7 percent of the total payload of a truck. However, the researchers calculate that 90 percent of carbon dioxide emissions could be recycled in this way.

The system is only a concept at the moment, and the researchers estimate that it will take several years to realize the system in the real world. The next step is to develop a prototype of the system to test out the experimental elements in practice.

Ultimately, Volvo hopes to have several autonomous vehicles traveling back and forth at once. They’ll be monitored by a control tower and max out at 40 km/h. While Vera is suited for short distances, it will be able to transport large volumes, and Volvo hopes it will offer greater efficiency, flexibility and sustainability. “Autonomous transports with low noise levels and zero exhaust emissions have an important role to play in the future of logistics, and will benefit both business and society,” said Mikael Karlsson, Volvo Trucks’ vice president of autonomous solutions.

While this is an important step, don’t expect to see Vera on streets near you any time soon. Large scale deployment will require further technology, safety, operations and infrastructure development. It’s likely some of that will happen in Sweden, which has become a leader in autonomous vehicle testing. Last month, Einride’s autonomous trucks began daily delivery tests on a public road in Jönköping, Sweden, and Engadget’s Billy Steele test drove one of Einride’s trucks from 1,200 miles away. With these trial runs, it’s becoming more evident that autonomous trucks will play a role in the future of shipping.

The very first eHighway launched in Sweden in 2016. The concept here is the same — the trucks use pantographs (the pickps on their roofs) to latch on to the overhead cables and draw electricity. Trucks can feed electricity into the grid when they brake, making the system particularly useful if there’s ever a jam.

The system won’t have a major impact for a while. Just five trucks will run the electrified stretch each day where roughly 10 percent of the road’s 135,000 daily vehicles are heavy trucks. That reduced emissions footprint could scale up as more trucks support the system, though, and could encourage trucking companies to go electric knowing that their cargo haulers could drive longer on a charge.