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Carbon Capture and Sequestration (CCS) is the process of extracting CO2 from stationary sources and piping it into deep underground storage. It's an old idea that’s been getting a lot of attention this year. Until now, CCS has been considered too expensive and inefficient to be a worthwhile endeavour.
Over the past fifteen years, the Quebec-based company,
CO2 Solutions has been developing a way to make the process less expensive and more environmentally viable. With their advancements in the field of
enzyme-enabled carbon capture, they are doing something that most environmental companies only dream about—they’re getting funding. The real possibility of scaled-up CCS, however, has some experts wondering if we really know what implications the largely experimental tecnology might have on subsurface environments.
From many angles, enzyme-enabled carbon capturing seems like a great idea. But, how exactly is this new technology addressing the old concerns of CCS?
To answer this question, DeSmog seeks the expertise of subsurface microbiologist,
Rick Colwell at Oregon State University to find out where the risks associated with CCS lie and if they are being addressed in government plans to implement the technology.
How it Works 
The traditional CCS process involves large, expensive equipment, solvents that require intense heat to capture the CO2 molecule and a lot of energy to move what eventually becomes liquified carbon. If the storage is far from the producer they may need to transport the CO2 over long distances to storage zones. According to the CO2 Solutions website, the cost of conventional CO2 capture “would raise the cost of producing electricity from [a] power plant by approximately 80%."
The goal of CCS is to funnel CO2 directly from stationary sources of carbon emission—things like power plants and tar sands—to storage areas up to two kilometers underground. Stationary sources are responsible for 49% of CO2 emissions, so that's a lot of product to store.
There are three storage zones for CO2.
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It can be compressed and pipelined several meters down to naturally occurring saline aquifers and salt deposits.
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It can be used in a process called Enhanced Oil Recovery (EOR). A method that injects CO2 into aging oil reservoirs.
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It can be stored near materials that contain calcium or magnesium. The website states: “this material can be carbonated to form mineral solids, locking the CO2 away while creating a neutralized material which may have commercial value.”
What CO2 Solutions is Doing
CO2 Solutions is developing “enzyme-enabled” carbon capture technology, which would require less energy to extract CO2 than solvents. The equipment would be smaller and less costly and, since the enzymes need less heat, the process is more environmentally viable. The carbonic anhydrase enzyme technology, according to the company, functions like an “industrial lung” and addresses the emissions needs for stationary producers.
And yet, this new technology doesn’t address the issue of storage. The carbon, though it may go through a more environmentally sound capturing process, isn’t less toxic to subsurface environments. There is scant existing knowledge about the effect CO2 would have on the little-known world of the underground.
Extremophiles of the Underground
Dr. Colwell’s research is primarily on subsurface microbial life called extremophiles—tiny organisms that live under the harshest conditions, hundreds of meters deep in Earth's crust. His expertise in subsurface Earth has led to his concern about the long-term health of these underground storage zones.
“The deep Earth represents an environment that human beings have come to expect something from. We depend upon water from deep in the Earth and we have energy sources that we depend upon for extraction, minerals and metals as well. Some of these environments are used for storage of things like nuclear waste and carbon dioxide.”
Once a little known area of research, subsurface microbiology came into focus because of the exploitation of underground environments.
“In the 1970’s and 80’s, it became clear that many of the underground environments that we depend upon had been altered by human activity. The best example is aquifers, ground water that we would typically pump either as potable water or for irrigation. It turned out that in the places where we had disposed of toxic waste, the water became contaminated.”
Studying subsurface extremophiles has been useful in addressing the possibility for clean up of these contaminated zones. These “micro-organisms can sometimes clean things up and make things better than the way that we left them.” Researching these extremophiles has the potential to address issues that range from healing contaminated ecosystems to the possibility of life on other planets.
Dr. Colwell said he is concerned about the effects of carbon storage on these microbes. He says he’s concerned about the deficit of research. “Any time that you move forward with a large-scale engineering project like this, in an environment that is not far away from systems like an aquifer, as a microbiologist, I have to be concerned. If this is an environment where organisms can exist, then they will certainly interact with the CO2.”
In order to seriously consider the viability of such a project, he thinks we would have to do a considerable amount of research on storage sites in order to have some idea of what the affects will be. “Right now we only have a handful of places that are doing this.” And that does not provide enough data to make an informed choice.
We would need “research that looks at the best ways to monitor surface locations for any potential leaks.” The risks of a leak would include the potential saturation of underground aquifers that are in use by humans, or the return of CO2 back into the atmosphere.
He recognizes that CCS operations are functioning in places like Norway and Algeria which, so far, have presented no major issues or concerns. However, he doesn’t think that the scale of these places offers a real example of the possible risks associated with North America.
When it comes to storing liquid carbon on a large scale like the tar sands, Dr. Colwell says, “we would need to understand the broader implications of doing something like that, whether it’s from the perspective of chemistry in sub-surface environments or hydrology, or the biogeochemistry of those environments [where the carbon is being stored].”
When asked if carbon sequestering is an environmentally viable solution to rising emissions Colwell said “in order to play a role in coping with the amount of CO2 that is going to the atmosphere because of human activities we would need a really large effort in terms of sequestration.”
He believes that CCS could only play a small role in a larger problem. “In order to truly address climate change, no single technology can take care of the entire problem.”
He concludes that we simply need more knowledge before we proceed.
“Knowledge is always a good thing if you are hoping to make sound decisions.”
