Carbon Capture and Storage

Production and Distribution of Electricity and Heat

Carbon capture and storage (CCS) technologies allow the reduction of carbon dioxide (CO₂) emissions from fossil fuels combustion in the electricity generation and in some industrial processes (e.g., the production of cement or the extraction of natural gas from fields with high CO₂ content). CCS technologies typically include three stages:

i) CO₂ capture by de-carbonization of fossil fuels (pre-combustion capture), separation from combustion exhaust gases (post-combustion capture), separation from gas streams with a high CO₂ content or capture of CO₂ from the atmosphere (Direct Air Capture);

ii) transport of CO₂ to storage sites by pipeline, ship or road tanker;

iii) geological storage in suitable sites such as deep saline aquifers, coal beds otherwise non-usable, depleted oil and/or natural gas fields. In the latter case, CO₂ can be used to facilitate the extraction of fossil fuels (enhanced oil/gas recovery (EOR/EGR)).

In combustion processes, CO₂ can be isolated either before combustion (pre-combustion capture) by gasifying the fuel (e.g., coal) and separating carbon dioxide from the resulting gaseous mixture, and after combustion (post-combustion capture) by separating it from the exhaust gases. A third possibility is represented by the oxy-combustion process, in which combustion takes place in an oxygen atmosphere, generating exhaust gases with a high CO₂ content and water vapor which can be easily separated by condensation after the removal of contaminants. In other industrial processes that produce CO₂, separation typically occurs from gas streams with high CO₂ content. Moreover, new technologies are being developed for the capture of CO₂ directly from the atmosphere, even when present in very low concentrations, through air contact with absorbent media.

CCS technologies are partly based on processes with good technical and commercial maturity, already widespread in some industrial sectors. However, their large-scale application in the electricity generation sector and other sectors with high CO₂ production (e.g., cement production) is hampered by problems of cost, regulation, social acceptance of geological storage, and process scaling-up. Currently, CCS technologies are employed in only a few plants on industrial and commercial scale

01-07-2022

Please Login to download the document