Environmental Science
Carbon Capture, Utilization, and Storage Technologies
Quick fact
The Sleipner project in Norway has been storing about 1 million tonnes of CO₂ per year under the North Sea since 1996—the equivalent of taking 200,000 cars off the road annually.
Why this is interesting
Every year, we release over 36 billion tonnes of CO₂ into the atmosphere. What if we could catch most of it before it escapes, and even turn it into something useful?
Read the full explanation
Understanding Carbon Capture, Utilization, and Storage Technologies
Think of CCUS as a three-step process. First, capture: imagine a giant chemical sponge that soaks up CO₂ from exhaust pipes of power plants or factories. There are different ways to do this—using chemical solvents that bind CO₂, membranes that filter it out, or burning fuel with pure oxygen to leave a pure CO₂ stream. Next, utilization: instead of storing the captured CO₂, we can turn it into products like synthetic fuels, plastics, or even concrete. Finally, storage: we inject the CO₂ deep underground into porous rock formations, such as depleted oil and gas reservoirs or saline aquifers, where it stays trapped for thousands of years. The whole chain aims to prevent CO₂ from reaching the atmosphere while creating economic value or permanent disposal.
A deeper explanation
The core mechanism behind CCUS is chemical separation or physical trapping. For capture, post-combustion uses solvents like amines that chemically react with CO₂; heating the solvent then releases pure CO₂ for collection. Pre-combustion, used in gasification, converts fuel into hydrogen and CO₂ before burning, making separation easier. Oxy-fuel combustion burns fuel in nearly pure oxygen, producing exhaust of mainly CO₂ and water vapor. For storage, CO₂ is compressed to a dense, liquid-like state and injected into geological formations. The primary trapping mechanisms are structural trapping by impermeable cap rocks, residual trapping in pore spaces, solubility trapping as it dissolves in brine, and mineral trapping as it slowly reacts with rock to form carbonates. Utilization often involves catalytic conversion: e.g., CO₂ plus hydrogen can produce methanol, a fuel and chemical feedstock. CCUS matters because it can capture emissions from existing infrastructure, offering a bridge while clean energy scales, and even enable negative emissions when combined with bioenergy (BECCS).