Carbon capture and storage (CCS) is the process of capturing waste carbon dioxide from industrial facilities or power plants, transporting it to a storage site, and depositing it where it will not re-enter the atmosphere. In this process, carbon is removed, usually as carbon dioxide (CO2), either prior to combustion of the fuel or after combustion in the exhaust stack. Capture technologies allow the separation of carbon dioxide from gases produced in industrial processes and electric generation by one of three methods: pre-combustion capture, post-combustion capture, and oxyfuel combustion.
The CO2 is then transported via pipeline or other means to a location where it can be stored. CO2 might be stored in deep underground geological formations or in the ocean, or by transforming it into mineral carbonates. Current research is primarily focused on geological formations including depleted oil and gas fields or deep saline aquifer formations. While most commonly envisioned as a means for reducing carbon emissions due to the combustion of fossil fuels, CCS can also be applied to biomass combustion resulting in carbon negative generation of electricity (meaning that net carbon emissions are negative).
While carbon capture and sequestration has been proven to work, it is not yet widely applied on a commercial scale. Most current applications capture CO2 for use in enhanced oil or gas recovery. This process pumps the CO2 into oil or gas wells to help stimulate production. A few pilot storage projects have been developed as of 2020. Costs of adding and operating technology for carbon capture and sequestration are high, as would be expected for a new technology. Whether costs will come down with research and development is uncertain. However, this concept may provide a useful tool in the battle to reduce greenhouse emissions from fossil fuel generation.