What Is Carbon Capture and Storage (CCS)? The Technology Explained
The basics: what CCS actually does
CCS works in three stages. First, CO2 is captured at an industrial source - a power plant, cement kiln or steel mill. Second, the gas is compressed and moved, usually by pipeline or ship. Third, it is injected deep underground into geological formations where it stays for centuries. The goal is simple: keep the carbon that was already dug out of the ground from re-entering the air.
How the three stages work
Capture is the hardest and most expensive step. The most common method is post-combustion capture, where exhaust gas is bubbled through a chemical solvent (usually an amine) that absorbs CO2. A second approach, pre-combustion capture, converts fuel into a hydrogen-rich gas before burning it. A newer and much costlier option, direct air capture (DAC), pulls CO2 straight out of ambient air rather than from a chimney. Transport usually means pipelines - hundreds of kilometres in some projects - or liquefied CO2 shipped by sea. Storage happens in depleted oil and gas fields or saline aquifers, typically one to three kilometres below the surface.
Why it matters
Renewables and batteries solve electricity, but cement, steel and chemicals still burn fuel directly and have few alternatives. International climate scenarios rely on CCS to handle these hard-to-abate sectors, and some models also assume large amounts of carbon removal later this century. Commercial-scale CCS has been running since the 1990s in Norway and the United States, but today the total captured volume remains a tiny fraction of global emissions.
The debate
Supporters argue CCS is essential for heavy industry and existing fossil infrastructure. Critics counter that it is expensive, slow to scale and can be used to justify continued drilling instead of faster electrification. The truth sits in between: CCS is unlikely to save fossil power plants at scale, but it is close to unavoidable for cement and steel. DAC, meanwhile, is still far too costly for wide use.
Where CCS is running today
CCS is not theoretical. The Sleipner project in Norway has been injecting about one million tonnes of CO2 per year into a saline formation under the North Sea since 1996, making it the longest-running storage operation in the world. Boundary Dam in Canada became the first commercial power-plant retrofit in 2014. More recently, direct air capture plants Orca and Mammoth in Iceland began locking small volumes of CO2 into basalt rock, where it mineralises within a couple of years, and Norway's Northern Lights project opened in 2024 as the first open-access transport and storage network, receiving CO2 shipped across borders by sea. The IEA CCUS Projects Database tracks every commissioned and planned facility worldwide, and its headline finding is consistent: operational capacity is growing, but announced projects still dwarf what is actually in the ground.
What it costs
Cost depends almost entirely on how concentrated the CO2 stream is. Capturing from ethanol fermenters or natural-gas processing plants, where CO2 makes up a large share of the stream, can cost in the range of $15-35 per tonne. Dilute streams such as power-plant flue gas or cement kiln exhaust run roughly $40-120 per tonne. Direct air capture, which scrubs CO2 at about 0.04% concentration, is the most expensive link in the chain - current estimates cluster in the hundreds of dollars per tonne. Each step up in dilution buys harder engineering: more fan power, bigger contactors, more solvent. This is why the cheapest early projects cluster around concentrated industrial sources, and why cost curves fall with cumulative deployment rather than automatically with time.
Frequently asked questions
Can CCS solve climate change on its own?
No. CCS is a complement, not a replacement. Analysts see it handling emissions from industries that cannot electrify; deep cuts in electricity and transport still depend on renewables and efficiency.
What is direct air capture (DAC)?
DAC is a CCS variant that removes CO2 directly from the atmosphere instead of from a power-plant chimney. It is flexible about location but currently far more expensive per tonne than capturing from an industrial source.
Is carbon capture the same as planting trees?
No. CCS is engineered storage in underground geology, measurable and permanent. Trees and soil absorb carbon but can release it in wildfires or when land use changes. Both have a role; they are not interchangeable.
How much CO2 is captured today?
Roughly 50 million tonnes per year across all operational facilities - under 0.2% of global energy-related emissions. Announced projects would multiply that capacity several times by 2030, but a large share have not reached final investment decision.
Where does the captured CO2 go?
Most is compressed and injected one to three kilometres underground into saline aquifers or depleted oil and gas fields. Some is used for enhanced oil recovery - controversial, since it can unlock more crude - or converted into synthetic fuels and building materials.
Sources & method: IEA — CCUS · US DOE — Carbon Storage · Global CCS Institute. · Luminesca News publishes plain-English explainers built with AI-assisted drafting and a published source list. · IEA — CCUS Projects Database · Back to Luminesca News