CCS stands for Carbon Capture and Storage, which is a process designed to prevent large amounts of carbon dioxide (CO2) from being released into the atmosphere from industrial sources. The process involves capturing CO2, compressing it for transportation, and then injecting it deep into a rock formation at a selected site, where it is permanently stored. The CCS process can be broken down into three major steps: capture, transportation, and storage. The captured CO2 is separated from other gases produced at large industrial process facilities such as coal and natural-gas-fired power plants, steel mills, cement plants, and refineries. CCS is often considered to be a relatively expensive process yielding a product which is often too cheap, hence carbon capture makes economically more sense where the carbon price is high enough, such as in much of Europe, or when combined with a utilization process where the cheap CO2 can be used to produce high-value chemicals to offset the high costs of capture operations. CCS technology is expected to use between 10 and 40 percent of the energy produced by a power station, which is called an energy penalty.

In summary, CCS is a process that captures CO2 emissions from industrial processes and stores them deep underground to prevent them from being released into the atmosphere.