CO2 Injection - CCUS Terms

Description:
CO2 Injection refers to the process of injecting captured carbon dioxide (CO₂) into underground geological formations for long-term storage or for enhanced oil recovery (EOR). This process involves compressing CO₂ to a supercritical state and then injecting it into suitable subsurface rock formations.

Explanation:
In the context of Carbon Capture, Utilization, and Storage (CCUS), CO₂ injection is a crucial step for ensuring the permanent sequestration of captured CO₂, thereby preventing its release into the atmosphere. Here’s how CO₂ injection works and its importance within the broader CCUS framework:

• Carbon Capture. Initially, CO2 is captured from industrial sources, power plants, or directly from the atmosphere using various capture technologies. Once captured, the CO2 is compressed and transported to an injection site.
• Utilization. While the primary purpose of CO2 injection is storage, it can also be utilized in enhanced oil recovery (EOR) processes. In EOR, CO2 is injected into declining oil fields to increase oil production. The CO2 helps to mobilize and displace the remaining oil, making it easier to extract. After the oil recovery process, the CO2 can be stored permanently in the same geological formation.
• Storage. The main goal of CO2 injection is to securely store CO2 in geological formations such as depleted oil and gas fields, saline aquifers, and unmineable coal seams. Depleted oil and gas fields are reliable for CO2 storage due to their proven ability to trap hydrocarbons for millions of years. Saline aquifers, which are porous rock formations filled with brine, offer vast storage capacity and are widely distributed, making them suitable for CO2 storage. Unmineable coal seams can adsorb CO2 onto the coal's surface, displacing methane that can be captured and used as natural gas, thus providing a dual benefit of CO2 sequestration and methane recovery.

Advantages:
CO2 injection offers several advantages within the CCUS framework. It provides a means of securely and permanently storing large volumes of CO2, significantly reducing atmospheric emissions and helping to mitigate climate change. The use of CO2 for enhanced oil recovery (EOR) can also make CO2 injection economically attractive by providing additional revenue from increased oil production. Additionally, the infrastructure developed for CO2 injection, such as pipelines and storage facilities, can support the broader deployment of CCUS technologies and promote the transition to a low-carbon economy.

Challenges:
Despite its advantages, CO2 injection faces several challenges. The process requires significant investment in infrastructure, such as pipelines, compressors, and injection wells. Ensuring the long-term integrity and safety of storage sites is critical, as any leaks could undermine the environmental benefits of CO2 storage. This requires rigorous monitoring, verification, and regulatory oversight. Additionally, public acceptance and regulatory approvals can be challenging to obtain, as communities may have concerns about the safety and environmental impacts of CO2 storage projects.

In summary, CO2 Injection is essential for promoting the development and deployment of Carbon Capture, Utilization, and Storage technologies. By providing a secure and permanent solution for CO₂ storage, injection technologies help achieve significant reductions in greenhouse gas emissions and support global efforts to mitigate climate change.