What is Carbon Capture and Sequestration (CCS)?
We all studied in our high school science classes that our atmosphere consists of CO2, by respiration animals release CO2 into the atmosphere and plants use the CO2 to synthesize their food. It is not rocket science and well known to all of us. Now arise the question: when do we realize it is a problem to mankind? Figure 1 shows the brief history of how seemingly harmless gas in our atmosphere got its bad reputation.
Figure 1 – Evolution of CO2 as primary global warming agent
(Source: NASA’s Global Climate Change Website)
Over the years, there has been lot of efforts from international community to find ways to reduce CO2 emissions or at least maintain current levels. One of the ideas is to capture the CO2 from the source of emission and store it underground. Some of the storage options are depleted oil and gas wells, salt caverns, ocean beds, conversion of CO2 to a product where it can be permanently tied up for very long time (cements, plastics).
Carbon capture and sequestration (CCS) is a technology proposed by scientific and industrial community in 1977 to capture carbon dioxide (CO2) emitted from power plants, gas processing plants and industrial facilities. Although the technology has been existent since 1920, the CO2 capture gained more attention due to the success of enhanced oil recovery (EOR) projects by CO2 in 1970’s. In EOR, the CO2 is transported via pipelines to the nearest oil producing field and injected into the reservoir to boost oil production.
The process of CCS typically involves three main steps (Figure 2):
Carbon capture: Separating CO2 from other gases emitted by power plants and industrial facilities.
Transport: The captured CO2 is then transported via pipelines, ships or trucks either as a gas or supercritical fluid to the storage site
Storage: Depleted underground geological formations will be filled with transported CO2 and expected to stay underground for very long time
Figure 2 – Steps Involved in CCS process
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