Carbon Capture and Storage (CCS) is an innovative technology which captures emissions at factories and fossil fuel power plants before transporting them underground for storage.
Most CCS projects currently in existence are tied to enhanced oil recovery, where CO2 injection increases production from depleted oil reservoirs.
Capture
Carbon capture and storage (CCS) is an innovative technology that reduces emissions from stationary sources such as coal- or natural-gas-fired power plants and industry sources such as ethanol production facilities or natural gas processing facilities, by sequestering excess CO2. Once captured, CCS allows companies to store CO2 permanently underground in geologic formations; helping meet WRI targets of 2degC warming (or 1.5degC warming in extreme cases).
Capture technologies range from chemical transformations before fossil fuels are burned (pre-combustion), gasification of the fuel in an oxy-fuel process using pure oxygen (post-combustion) and direct air capture using biological processes such as photosynthesis to directly capture CO2. After capture, CO2 must then be compressed to reduce its volume before being chilled to near ice conditions for transport via pipeline to its storage site; this requires significant energy use as well as carbon emissions monetization to make CCS cost effective.
Compression
Carbon capture and storage (CCS) technologies capture CO2 emissions from power plants and industrial processes and store it underground permanently, either via pipeline, rail or road transportation to an approved storage site or injection deep underground into geological formations such as depleted oil reservoirs or saline aquifers.
Pre-combustion carbon capture in power plants utilizes chemical solvents to separate CO2 from flue gas. Once separated, this CO2 can then be gasified to form synthesis gas or syngas for use by conventional steam turbines to generate electricity.
However, unlike Boundary Dam or Petra Nova projects, most commercial CCS facilities were not intended as climate technologies; rather they serve commercial needs such as testing new technologies at scale or signalling corporate decarbonisation strategies; or providing revenue from selling by-product CO2 to oil field operators for enhanced oil recovery. As such, their track records can vary considerably; sometimes due to issues of ash contamination or solvent foaming they face unexpected difficulties that compromise their operation.
Transport
Carbon capture technologies hold great promise for cutting emissions from transportation sectors like transport. Since this sector accounts for such a significant share of global emissions, energy-saving innovations such as carbon capture could make transportation more sustainable.
Capture usually occurs at large point sources such as power plants and industrial facilities that use fossil fuels to produce electricity, cement, steel or other products. CO2 can be captured either pre-combustion through chemical conversion before combustion occurs (pre-combustion) or post combustion via physiological processes after it leaves the smokestack (post combustion). Once captured it can then be compressed and transported via pipeline, ship, rail or truck for long-term storage in deep geological formations such as depleted oil and gas reservoirs, coalbeds or deep saline aquifers for long-term storage in deep geological formations such as depleted oil reservoirs, coalbeds or deep saline aquifers.
CO2 captured from CCS projects can also be utilized in carbon-free energy generation or enhanced oil recovery (EOR), two uses which require relatively small volumes. Many CCS projects currently being built are specifically to support EOR, with revenues generated through selling captured CO2 to EOR operators helping cover some of its cost.
Storage
Carbon capture and storage technologies offer a way to mitigate fossil-generated emissions before they reach the atmosphere, by collecting CO2 at power plants or other sources before transporting and storing it underground for permanent disposal.
CO2 captured from emissions sources is compressed and chilled before being sent directly to its storage site, usually via pipeline; although ship transport is also an option. At its destination, captured CO2 is then pumped down 2,500-foot wells into deep geological formations like oil/gas reservoirs or saline aquifers for long-term storage.
Structural trapping refers to storing CO2 within porous rocks, where its release cannot migrate into shallower formations or the atmosphere. Saline formations offer the largest potential volume for storage; however, other geological methods are being considered – one being using layers and faults similar to those seen in offshore oil platforms in the Gulf of Mexico as storage spaces.