Carbon capture and storage (CCS) refers to an array of technologies designed to dramatically decrease fossil fuel emissions before they reach the atmosphere, such as coal, natural gas or other fossil fuel power plants.
CO2 can be captured and permanently stored in geologic formations such as deep saline aquifers, depleted oil fields, unmineable coal beds or basalt formations.
Capture
Carbon Capture and Storage (CCS) technology entails collecting carbon emissions from industrial processes before they enter the atmosphere, with the goal of keeping global temperature increases under 1.5-2 degreeC. CCS could play an essential part in energy mix scenarios designed to limit global temperature increases by providing a solution.
At a power plant or industrial facility, CO2 is extracted from flue gas by using chemical and physical processes. This can occur either prior to combustion (pre-combustion CCS), during combustion (post-combustion CCS), or using alternative fuel such as oxy-fuel combustion.
CO2 captured from emissions is then transported to storage sites for long-term storage. This requires significant energy; compressing it into supercritical phase, chilling it to liquid state, and transporting at high pressures and cold temperatures – typically to deep geological formations such as oil or gas reservoirs.
Compression
CCS technology can reduce CO2 emissions from power plants and industrial facilities by isolating its component parts, transporting, and injecting into deep underground geologic formations.
Before CO2 can be stored for long-term use, it must first be purified. Power plant flue gas contains contaminants like particulates and oxides of nitrogen and sulphur as well as moisture that must be separated out and eliminated before pressurisation and chilling can reduce its volume to prevent corrosion during transportation and storage.
At present, 41 commercial CCS projects are operating globally, though most were not intended for climate purposes and plants using them often operate at below their full design capacity in order to maximise power output or sell by-product CO2 to oil field operators for enhanced oil recovery (EOR) purposes. This makes CCS less effective at mitigating global warming than it otherwise might.
Transport
Carbon dioxide captured from industrial sources must be transported to storage sites for safekeeping. Pipelines are the preferred mode of transport due to being already used for natural gas transport and can easily be modified to transport CO2. Trucks and ships may also be employed, although pipelines tend to be the more economical choice.
Transport of carbon dioxide requires compressing it into liquid form for easier passage through pipes, and cleaning and inspecting it to meet stringent purity and temperature specifications.
CCS holds immense promise to reduce emissions from transportation sectors – which account for much of global emissions. Many initiatives and projects are underway to develop CCS technology further for transportation applications like electric vehicles and biofuels.
Injection
Carbon capture and storage (CCUS) plants capture CO2 from flue gas for use in industrial processes like making concrete or synthetic fuels; any excess is then stored underground, either depleted oil and gas reservoirs or saline aquifers.
These sites must typically meet several criteria in order to be safe and effective storage locations: an intact confining zone and sealing layers above the injection site, sufficient porosity for CO2 storage purposes, as well as sufficient depth to prevent leakage pathways.
Snohvit encountered several early technical challenges, such as lubricants that entered its CO2 stream and equipment malfunctions; these were all expected for such a groundbreaking technology and can easily be addressed.
Storage
Carbon capture and storage (CCS) is one way of reducing industrial CO2 emissions. Capture processes remove CO2 from gas streams at emitters such as power plants or cement factories before transporting and storing deep underground for long-term management.
CO2 is injected into porous rock formations such as saline aquifers or depleted/inactive oil and gas reservoirs for storage, where it will remain secure against leakage into deeper rock layers or the atmosphere. Monitoring sites ensure that CO2 remains within these storage formations.
CCS technology, while facing formidable hurdles in development, may reduce overall emissions footprint of energy systems and help coal-dependent countries reduce greenhouse gas emissions to mitigate climate change.