The modified wagons purify the air of CO2 and help

Modified Railcars Clean the Air of CO2 and Help Mitigate Climate Change

  • New research shows rail systems around the world could be harnessed to help mitigate climate change and clean our air of CO2
  • Researchers from the University of Sheffield are working with US company CO2Rail to design direct air capture equipment that can be used in special carriages placed with trains already running
  • On average, each complete braking maneuver of a train generates enough energy to power 20 homes for an entire day – so far this enormous amount of sustainable energy has been wasted
  • If the energy from every stop or deceleration of every train in the world could be captured, it would harness 105 times more energy than the Hoover Dam produces in the same period.

Rail systems around the world could help mitigate climate change and clean the air of CO2 by capturing the sustainable energy generated when trains stop and decelerate.

US start-up CO2Rail Company worked with a team of world-renowned researchers, including engineers from the University of Sheffield, to design Direct Air Capture (DAC) technology that removes carbon dioxide from the air, which can be used in special environments. wagons placed with trains already running in regular service.

DAC cars operate by using large air intakes that extend into the wake of the moving train to move ambient air into the large cylindrical CO2 collection chamber and eliminate the need for the power-hungry fan systems that are required with stationary DAC operations.

The air then goes through a chemical process that separates the CO2 from the air and the carbon dioxide-free air then exits from the rear or underside of the car and back into the atmosphere.

Once a sufficient quantity has been captured, the chamber is closed and the harvested CO2 is collected, concentrated and stored in a liquid tank until it can be emptied from the train during a shift change or a refueling stop in normal CO2 tank cars. It is then transported into the circular carbon economy as a value-added feedstock for CO2 utilization, or to nearby geological landfills.

Each of these processes is powered exclusively by sustainable energy sources generated on board which do not require any external energy input or off-duty charging cycles.

When a train pumps the brakes, its energy braking system converts the forward momentum of the train into electrical energy in the same way as a regenerative electric vehicle. Currently, this energy is dissipated in trains in the form of heat and evacuated through the top of the locomotive during each braking manoeuvre.

Professor Peter Styring, director of the UK Center for Carbon Dioxide Utilization at the University of Sheffield and co-author of the research, said: “The direct capture of carbon dioxide from the environment is increasingly becoming an urgent necessity to mitigate the worst effects of climate change.

“Currently, the huge amount of sustainable energy created when a train brakes or decelerates is simply lost. This innovative technology will not only use the sustainable energy created by the braking maneuver to harvest significant amounts of CO2, but it will will also benefit from the many synergies that integration into the global rail network would bring.

“The technology will harvest significant amounts of CO2 at much lower costs and has the potential to achieve annual productivity of 0.45 gigatonnes by 2030, 2.9 gigatonnes by 2050 and 7.8 gigatonnes by 2075, with each car having an annual capacity of 3,000 tons of CO2 in the short term.

Unlike stationary DAC operations, which require large areas of land to build equipment and to build renewable energy sources to power them, CO2Rail would be transient and generally invisible to the public. The potential impact of this technology was recently boosted when European transport organizations announced earlier this month that they were committing to tripling the use of high-speed rail by 2050 to limit air travel CO2-intensive.

Eric Bachman of CO2Rail Company, said: “On average, each full braking maneuver generates enough energy to power 20 average homes for an entire day, so it’s not a negligible amount of energy.

“Multiply that by every stop or deceleration for almost any train in the world and you have about 105 times more power than the Hoover Dam produced over the same period, and it was a hydroelectric construction project that lasted six years and cost $760 million in today’s dollars.

He added: “Imagine getting on a train every morning, seeing the attached CO2Rail cars and knowing that your daily commute to work is actually helping to mitigate climate change.

“It will work the same way with freight, if there is a choice between rail and another mode of transport, I think this technology will influence many shippers.”

The team, which includes researchers from the University of Sheffield, University of Toronto, MIT, Princeton, business and industry, found that every direct air intake car can reap about 6,000 metric tons of carbon dioxide in the air per year and more as technology develops. Additionally, since the trains are capable of accommodating multiple CO2Rail wagons, each train will harvest a corresponding multiple of CO2 tonnage.

With its sustainable energy requirements supplied exclusively by train-generated sources that are at no additional cost, savings of 30-40% per tonne of CO2 harvested can be achieved from energy inputs alone.

This, along with other significant savings such as land, brings the projected cost at scale to less than $50 per ton and makes the technology not only commercially viable but commercially attractive.

Professor Geoffrey Ozin of the University of Toronto and co-author of the study, said“At these price points and with its enormous capabilities, CO2Rail is likely to soon become the premier megaton-scale provider, the premier gigatonne-scale provider and the largest global provider of direct capture deployments of air in the world.

“Carbon neutral in regular transport, then significantly carbon negative with ambient air DAC operations. A win-win technology in all respects and a “save humanity” technology.

The team is also working on a similar system that can remove CO2 emissions from the exhaust of diesel-powered locomotives, as is universally common in North America and other parts of the world. With the growth of sustainably sourced rail electrification systems, this one-off capacity on diesel lines would make rail the world’s first carbon-neutral large-scale mode of transportation.

Research titled: “Direct carbon capture in the air based on the rail” is published in the Future Energy section of the journal Joule.

Media Contact: Amy Huxtable, Head of Media and Public Relations, University of Sheffield, [email protected], 07725 213702


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