CCS Applications

Addressing climate change and reducing atmospheric CO₂ levels requires a three-pronged approach:

Reduce or eliminate sources of carbon emissions whenever practical (for example, by using renewable energy sources like wind- and solar-generated electricity)
Capture CO₂ emissions from large sources before they are released to the atmosphere and store them in geologic repositories (so-called carbon capture and storage, CCS), and
Recapture carbon that has already been released to the atmosphere, or that is generated from sources not amenable to CCS, such as small and/or mobile CO₂

Recapturing CO₂ that has already escaped to the atmosphere is called Direct Air Capture (DAC), and it’s difficult. Faculty and students at SIU Carbondale, and its partners, have developed a novel DAC method that relies on natural processes to capture and concentrate carbon from the atmosphere, then converts that carbon into a form that is readily stored deep underground. This accomplishment was recently recognized by the Musk Foundation, which awarded the SIU Carbon Down Under team an XPRIZE for Carbon Removal - one of only 23 awarded worldwide.

Although it is important for regulating the Earth’s climate, CO₂ is only a minor component of the atmosphere, (currently about 0.041%), which makes capturing it directly from the air very challenging. But plants naturally take carbon out of the atmosphere by photosynthesis. In fact, one pound of plant mater contains about the same amount of carbon as one million liters of air. Collectively, plants take up between 12 and 16 Gigatonnes of carbon from the atmosphere every year – and every year that carbon is released back into the atmosphere when plant-derived wastes decompose. SIU’s approach intercepts that process by capturing plant-derived wastes and uses a novel technology, developed at SIU, to break down those wastes into water-soluble products that can be easily injected into spent oil and gas reservoirs, deep saline aquifers and other suitable geologic storage sites, where the carbon is safely sequestered for millennia.

SIU’s process is technologically simple and inherently environmentally benign – it uses only heat, water and oxygen to achieve its purpose. The product of this process is a tea-like, aqueous liquid that retains almost all of the carbon captured from the atmosphere when the plants grew. In this form, the carbon can be readily handled with conventional equipment, and is easily injected deep underground. Once it is in place, deep subsurface microbes hungrily metabolize the carbon, locking it away for millennia.

There are numerous advantages to this approach compared to existing DAC technology. First, plants do all the hard work of capturing and concentrating the carbon for us, which has consistently been the challenge for existing DAC methods. We already grow plants on a vast scale, so most of the waste carbon that could be captured this way is already being produced. That means that agricultural producers and rural communities can become major players in combating climate change. But SIU’s process is not limited to agricultural wastes. Virtually any form of organic waste that can trace its carbon back to plants can be sequestered this way, including forest wastes, kitchen wastes, yard wastes, and even manure/sewage. That means that everyone can play a role in combating climate change. Much like post-consumer recycling of paper, plastics and metals, anyone can collect and contribute organic wastes for sequestration, reducing pressure on landfills and other “disposal” systems, and helping to rebalance the Earth’s climate at the same time. This breakthrough establishes a new paradigm in DAC approaches to addressing climate change. Let nature do its thing, then only intervene to sequester the carbon that nature captured for us. It’s doable. We can limit, and perhaps reverse climate change, and SIU Carbondale and its partners are leading the way.