What is carbon capture and storage (CCS), and what is one major challenge to its widespread deployment?

• A. CCS is a process that stores energy to improve efficiency.
• B. CCS captures CO2 from emission sources and stores it in space in geologic formations.
• C. CCS converts CO2 into useful chemicals for profit.
• D. CCS captures CO2 from emission sources or air and stores it underground; challenges include high cost, energy penalty, storage security, and regulatory frameworks.

Answer: (D)

CCS works by capturing CO2 produced by power plants and industrial processes (and increasingly directly from the air), then transporting and injecting it into deep geological formations for long-term underground storage. This description covers both the capture step and the underground storage aspect, which is what CCS aims to do to prevent CO2 from entering the atmosphere. A major hurdle to deploying CCS widely is the cost and energy required for capture—it’s energy-intensive and expensive to pull CO2 out of emissions streams and compress it for transport. Add in concerns about the long-term security of the stored CO2 and the need for robust regulatory and monitoring frameworks, and you have significant barriers to scaling up. Other ideas like storing energy, converting CO2 into chemicals, or storing CO2 in space don’t describe the underground storage and long-term containment that CCS is designed for.