Novel Ways to Mitigate Atmospheric CO2

Posted on December 22, 2022

In six decades, atmospheric CO2 increased from 320 to 420 ppm. That 25% increase warmed the atmosphere one full degree Centigrade (1.8° F). Now, there’s a global effort to limit the increase by 2050 to a 0.5° C maximum. In two centuries, the acidity of the oceans is up 30%.

Given CO2’s impact, it is hard to imagine that the atmosphere is only 0.04% carbon dioxide. Interestingly, the Earth’s atmosphere contains 23 times more argon than CO2. Without carbon dioxide’s heat absorbing capacity, ice would encapsulate the planet. Still, the addition of several gigatons of CO2 to the atmosphere every year causes a ripple effect impacting land, sea, and air. In short, planet Earth’s entire ecosystem.

CO2 emissions come from both natural and human-produced sources. Natural sources include respiration, decomposition, and ocean release. Primary human sources include transportation, concrete and steel production, and deforestation.

Since the dawning of the Industrial Age, the surge in human-produced CO2 has upset the delicate balance. Burning fossil fuels accounts for 87% of human-produced carbon dioxide. Deforestation and other land use changes account for another 9%. Industrial processes are responsible for 4%. In cement production, 90% of energy use relates to firing the kilns.

Novel Carbon Capture Tech

New carbon mitigation strategies are vital to the quest for carbon neutrality. As McKinsey notes, “New, innovative technologies to alter the composition of cement and to offer alternative solutions may be needed to reach the decarbonization targets set for 2050.”

Researchers have already introduced a prodigious array of carbon capture technologies. Problems persist, as some resist scaling while others are too expensive. Some focus on the air while others are land-based. Still others focus on seawater.

Air removal includes tech like temperature swing membranes and mineral sorbent cycling. Calcium mineral cycling and electrochemical scrubbing are two other possibilities. On the land, there’s everything from reforestation to algae agriculture. Electrochemical capture via peridotite mineralization is another innovative technology. Seawater tech includes ocean alkalinization achieved using mine waste. There’s also CO2 capture using electrolysis and separation membranes.

Direct Air Capture (DAC)

Grabbing CO2 directly from the air is no small task. After all, the earth’s atmosphere weighs approximately 5.5 million gigatons, or 10 times the weight of the entire human race. Fortunately, positive effects occur at the gigaton level, a tiny fraction of the atmosphere’s total mass.

Point-source carbon capture technologies aim at power plants and other individual emitters. By contrast, direct air capture facilities suck carbon dioxide straight out of the overall atmosphere.

DAC gains momentum as companies seek carbon removal credits to offset their emissions. New American projects are coming on the heels of the passage of the Inflation Reduction Act. The bill provides billions of dollars to address global warming. For example, it increases the government subsidy for carbon removal from $50 to $85 per metric ton. This increase may move a variety of prospective projects from the red to the black.

Direct air capture is a key element of the IEA’s Net Zero by 2050. The IEA published its flagship report in May 2021. It notes that current direct air capture is minuscule – 0.01 millionth of a ton per year. In the IEA scenario, direct air capture would reach 85 million by 2030. This increases more than 10-fold to 950 million tons by 2050. While that sounds like a lot, it is still less than a single gigaton.

At present, there are 18 direct air carbon capture facilities in the world. All are in Europe and North America. Thousands of facilities must be constructed for DAC to have a discernible impact on global warming.

Other promising projects take advantage of existing infrastructure. For example, CO2 Rail intends to deploy specialized rail cars to snatch CO2 from the air. It may have the potential to become the first gigaton-scale direct carbon capture technology on the planet. CO2Rail believes it can reduce the cost of its carbon capture to $50/ton. Competing technologies often cost double that or more.

Case Study: Project Bison

CarbonCapture’s “Project Bison” is a new DAC initiative projected to be online by late 2023. Initial capacity will be modest, about 1/300 of the emissions of a single coal-fired power plant. Capacity will increase in stages. The facility will not reach its five megaton capacity for years.

Why Wyoming for carbon capture? First, infrastructure and workers from the declining coal industry are valuable assets. Second, Wyoming's geology is conducive to carbon sequestration.

The technology is quite simple. Solid sorbents remove most of the CO2 from the air passing through them. Heating the material to about 185 degrees F releases the CO2. This allows the sorbent to be repeatedly redeployed. Each CarbonCapture module is roughly the size of a 40-ft shipping container. It is possible to stack them.

XPrize Carbon Removal Competition

The first round of the XPrize Carbon Removal competition concluded in 2021. CarbonCure and CarbonBuilt split the $15 million first place award. Both focused their research on the concrete industry.

In a new competition, XPrize offers $100 million to further incentivize carbon removal innovation. The competition is dedicated to “fighting climate change and rebalancing Earth’s carbon cycle.” Entrants propose carbon capture from the air, sea, land, and rocks. In this new competition, every carbon removal project must demonstrate gigaton scalability.

In November 2021, the first $5 million went to a total of 23 student research teams. In early 2022, Milestone Award winners received $1 million each. The eventual winner of the Grand Prize gets $50 million.

About PACA

The Pennsylvania Aggregates and Concrete Association (PACA) reports on industry innovation via The team at PACA welcomes any questions you may have about your upcoming concrete project. Please contact us at your convenience.

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