Carbon Sequestration
Carbon sequestration from the air and industries primarily involves advanced technologies designed to capture and store CO₂, either directly from the atmosphere or as emissions from industrial sources. Here’s how each type works:
Carbon Capture and Storage (CCS) – Sequestration from Industries
How it Works: Carbon capture and storage (CCS) technology captures CO₂ emissions directly from large industrial sources (e.g., power plants, cement factories, steel mills) before it is released into the atmosphere.
Capture Methods: Three main methods are used:
Pre-combustion capture: CO₂ is removed from fuels before combustion, often in processes like coal gasification.
Post-combustion capture: CO₂ is extracted from the flue gases after combustion using chemical solvents.
Oxy-fuel combustion: Fuels are burned in pure oxygen, creating flue gases that are mostly CO₂ and water, making it easier to capture CO₂.
Storage and Utilization: The captured CO₂ is compressed, transported, and stored underground similarly to DAC, or repurposed for Enhanced Oil Recovery (EOR) in which it is injected into oil fields to extract additional oil. Alternatively, the CO₂ can be used in manufacturing processes, for example, in the creation of chemicals, biofuels, and synthetic materials.
Challenges and Costs: CCS is generally more economical than DAC but still faces challenges, such as requiring a substantial infrastructure to capture, transport, and store CO₂ safely and permanently.
Direct Air Capture (DAC) – Sequestration from Air
How it Works: Direct air capture (DAC) technology uses large fans to pull ambient air into contact with chemical sorbents (like hydroxide or amine solutions) that react with CO₂, capturing it from the atmosphere.
Storage Options: Once captured, the CO₂ can be compressed and either:
Stored underground in geological formations like saline aquifers (deep rock formations filled with salty water) or depleted oil and gas fields, which trap CO₂ for long-term storage.
Utilized in products like carbon-neutral fuels, building materials (e.g., concrete), or carbonated beverages, providing a commercial incentive for captured CO₂.
Challenges and Costs: DAC requires significant energy, especially for regenerating the sorbents to release CO₂, making it currently more expensive than other methods. However, advancements are improving efficiency and lowering costs.