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Future trains could utilise carbon capture on wheels

Trains of the future could scrub the air of carbon dioxide rather than pumping it out of their smokestacks. The new concept, outlined in science journal Joule, could reportedly capture emissions for less than $50 USD per ton.

As it stands, the only thing we’re on track for is dangerous levels of climate warming.

A recent consensus among environmental scientists, is that transitioning away from pollutant industry practices will not be enough meet the terms of the Paris Accord. Using green tech to sequester existing emissions is now deemed essential too – 10 gigatons annually by 2050, to be precise.

That’s easier said than done, however. Developing effective and affordable carbon capture technology is one thing, but there’s also sizable land and energy footprints to deal with.

A popular solution is to retrofit old buildings with smaller scale devices to create circular power systems. A Raddison hotel in the US, for instance, is converting carbon from its hot water tanks into potash, which is useful for making soaps and shampoos.

Ideally, in the coming years, we will also create portable ‘Direct Air Capture’ modules that can soak up greenhouse gases on the move. A research cohort from Canada, the US, and the UK recently unveiled an exciting concept for such a device in the energy journal Joule.

The entry outlines a mission to attach DAC devices directly to modified freight trains, so they’re removing CO2 from the air whilst rumbling along track lines.

Roughly the size of a regular train car, each unit is reportedly capable of drawing 6,000 tons of carbon from the atmosphere each year.

Game-Changing Rail Car Acts as a Mobile, Self-Powered System for Carbon Capture - autoevolution
Credit: CO2Rail

While most DAC innovations range from $250 to $600 per ton of isolated gas, absorbing the same quantity in this case would cost just $50. The high energy expense associated with powering up giant fans to force atmospheric air inside machines isn’t a hindrance here.

This is largely because there is no need to artificially generate airflow on a train. Instead, this apparatus is aerodynamically shaped to draw ambient air into its vents while the train is moving. Once inside the chamber, it continually blows over a sorbent material which locks CO2 away.

Once full carbon capacity is reached onboard, the chamber will automatically seal itself. These liquefied emissions can then be transferred in tanks to disposal or industrial companies during fuelling stops.

Modified rail cars clean air of CO2 and help mitigate climate change
Credit: CO2Rail

Speaking of which, impressively, the power needed to keep these trains barrelling over long distances can be provided entirely by ‘regenerative’ braking systems.

If you’re not a locomotive enthusiast, this is essentially the same thing you’d find in an electric car; where kinetic energy from braking is converted into electricity and then stored in the vehicle’s central battery.

After all, what good would it be pumping out emissions at one end of a train and then capturing them at the other?

CO2Rail’s chief technical officer, Eric Bachman, is ambitiously pushing for 400,000 of these DAC rail cars to be in service before 2050 – a total that researchers estimate would remove approximately 2.9 gigatons of CO2 from the atmosphere every year.

If my calculations are correct, this green freight armada would cover close to 30% of the entire target needed for sequestered carbon by 2030. Suffice to say, we’re well and truly on board.