CO₂ Capture and Storage

7. How can CO₂ be stored in other materials?

• 7.1 Can CO₂ be transformed and stored in solid form?
• 7.2 What are the industrial uses of CO₂ and can they reduce CO₂ emissions?

7.1 Can CO₂ be transformed and stored in solid form?

CO₂ can be converted virtually permanently into a solid form through chemical reactions with extracted minerals that are naturally occurring, such as calcium oxide (CaO) to produce limestone (CaCO₃) or magnesium oxide (MgO) to produce dolomite (MgCO₃). As a result of the reaction, no CO₂ would be released into the atmosphere, there would be little need to monitor the disposal sites, and the associated risks would be very low. Large amounts of energy and minerals, however, are required for this technology. Greater improvements would be needed before it could become a real option. More...

7.2 What are the industrial uses of CO₂ and can they reduce CO₂ emissions?

Exploiting captured CO₂ in industrial chemical processes in industry is technically possible, but it has only modest potential for actually reducing emissions. The total industrial use of 120 MtCO₂ per year is very small compared to the emissions induced by human activities (over 30 000 MtCO₂ per year). Two thirds are used to produce urea, which is used in the production of fertilizers and other products. Other uses include: horticulture, refrigeration, food packaging, welding, beverages, and fire extinguishers.

In addition, most of these industrial products release their CO₂ content back into the atmosphere after few days or months. Only a small proportion – roughly 20 MtCO₂ per year – is stored for up to several decades and only up to 1 MtCO₂ per year for a century or more. Therefore, CO₂ capture for industrial uses could only bring an insignificant contribution to climate change mitigation. More...