What is Carbon Capture and Storage?
Page last updated:15 June 2026
Carbon capture and storage (CCS) involves capturing carbon dioxide (CO₂) from industrial sources, such as cement, fertilizer and LNG production, and injecting it deep underground into sedimentary rocks such as sandstone. The CO2 is stored in the tiny pore spaces present between the grains of these rocks at depths typically around 2 kilometres underground.
CO2 is a greenhouse gas that occurs naturally and is also emitted as a result of human activities such as burning fossil fuels, agriculture, and other industries. CO2 emitted as a result of human activity is also called anthropogenic CO2.
CO2 can be captured and injected deep underground for permanent storage. Natural accumulations of CO2 in the subsurface and natural gas fields provide good examples of how it can be permanently trapped underground.
CO2 is captured from stationary emissions sources such as natural gas production, hydrogen production and industrial facilities like fertilizer or cement manufacturing plants.
Research is underway to develop cost effective and efficient methods to extract CO2 directly from the air to generate new products or for geological storage, also known as direct air capture and storage (DACS).
CO2 can be transported from the emission source to the storage location via pipelines, ships, by road (truck) or rail, much like natural gas.
At the storage location, CO2 is injected deep underground into a suitable geological formation for permanent storage, such as saline aquifers (e.g. sandstones that are filled with brine) or depleted oil or gas fields.
Within the reservoir rock, CO2 is initially trapped within the pore spaces between grains and prevented from moving out of the formation by overlying impermeable rocks that act like seals. Over time, the CO2 dissolves into the formation water, eventually reacting to form new minerals.
Instead of storing CO2 underground, captured CO2 can be used to make products. For example, CO2 can be used to create fertilisers, synthetic fuels or building materials. Currently, most of the CO2 that is used by industry to create these products is supplied from naturally occurring geological accumulations. Captured anthropogenic CO2 could eventually replace some of these natural sources.
Monitoring, mitigation and verification (MMV) of CO2 in the subsurface is a critical part of the CCS process and usually mandated through regulations and legislation.
The purpose of MMV is to make sure that the injected CO2 is safely and permanently stored. Monitoring techniques can include time-lapse seismic, a variety of down-hole sensors, fluid and soil gas analysis, and even aerial or satellite imaging.
