Introduction: What is CCS (Carbon Capture and Storage)
By Cormac Rea

It is now common knowledge that greenhouse gases such as carbon dioxide (CO₂) are threatening to our climate. And while individuals try to cut their own emissions, scientists and researchers are working furiously to develop large-scale solutions — solutions that can be quite challenging for the average person to understand. Here’s a simple rundown of one promising advance: carbon capture and storage (CCS).

CCS is a process of controlling carbon dioxide through capture, processing and storage. Deep injection of CO₂ has been a common practice in the oil and gas industry for decades to enhance oil recovery from expiring wells. Now, researchers are turning to the same process to curb emissions. Power generation from the combustion of fossil fuels is one of the greatest emitters of CO₂, pumping out nearly a third of global emissions. Depending on technique, CO₂ can be captured before, after or during the combustion process. Sometimes a chemical reaction or solvent is used to separate the CO₂ from other substances or the gas is captured at large point source vents, commonly known as flues. Then scientists or engineers compress the captured CO₂, sometimes creating a dense liquid, suitable for transport by ship, truck or pipeline to the storage reservoir. The storage of carbon makes this method truly remarkable.

In order to combat climate change, the CO₂ must be stored for hundreds or thousands of years without leakage or environmental degradation. Geological formations are the most commonly used sites. In the Weyburn field in Saskatchewan, for example, CO₂ is being injected into a used oil reservoir and is being sealed under dense caprock.

CCS has garnered interest from a variety of governments and industries, yet there are some concerns. Depending on the method used to capture carbon, other types of waste or emissions, such as solvent residue or sludge can be produced.

Ultimately, the price tag could be the limiting factor when it comes to CCS. Depending on the method, capture, transport and storage of CO₂ may cost anywhere between $5-$115/tonne. Large, expensive equipment and powerful solvents are needed, which use extra energy and incur monetary and efficiency costs. Still, over the long term, experts suggest CCS systems will save considerably on the ultimate costs associated with increasing greenhouse gases and climate change.