A Train Car That Removes Carbon Dioxide from the Air

What if a train could remove carbon dioxide from the air through its everyday commute?

New research published July 20 in Joule led by E. Bachman, the founder of the research company CO₂Rail in Austin, TX, proposes a way to install a direct air capture device on existing train cars.

Direct air capture is a type of technology that can remove carbon dioxide from the air. As a dangerous greenhouse gas, removing CO₂ from the atmosphere can be an efficient way to reduce carbon emissions. However, the authors of this paper point out that traditional methods of direct air capture can take up large amounts of land and require high energy inputs.

Additionally, direct air capture facilities are unpopular with residents of the areas in which they are built.

"Rail-based direct air capture cars would not require zoning or building permits and would be transient and generally unseen by the public,” said co-author Geoffery Ozin, a researcher from the University of Toronto.

The train cars with large vents would eliminate the need for large, energy-inefficient fans that intake air. As the train travels, it captures the carbon dioxide, and once it's full, the vents can be closed, and the CO₂ can be stored in a liquid reservoir that can be emptied when the train stops.

The system would be used to offset the energy produced when a train uses its breaks. Bachman said that the energy generated from applying the breaks generates enough to power 20 average homes a day.

Using the rail system already in place is the largest advantage of this proposal since there isn’t a need for expensive infrastructure. The researchers estimated that their train cars would be able to remove up to 6,000 tons of carbon dioxide per year. Additionally, the estimated cost is less than $50 per ton of CO₂, which is commercially feasible and attractive, Bachman said.

The group hopes that their technology will be able to offset the trains’ carbon emissions and make the entire rail system more energy efficient, further reducing the impact on our changing climate.

Sources: CellPress, Joule