Saline Aquifers - CCUS Terms

Description:
Saline Aquifers are underground layers of porous rock filled with saline (salty) water, typically found at depths greater than 800 meters. These geological formations are considered suitable for the long-term storage of carbon dioxide (CO2) due to their large storage capacity and widespread availability.

Explanation:
Saline Aquifers are significant in the broader framework of Carbon Capture, Utilization, and Storage (CCUS) because they provide a viable option for the secure and permanent storage of captured CO2. Here’s how saline aquifers integrate with the CCUS framework:

• Carbon Capture. While saline aquifers are primarily involved in the storage aspect of CCUS, they indirectly support carbon capture by providing a reliable storage solution for captured CO2. This ensures that captured CO2 can be securely stored, encouraging investment in carbon capture technologies and reducing overall greenhouse gas emissions.
• Utilization. For CO2 utilization projects that produce surplus CO2, saline aquifers offer a storage solution for excess CO2 that cannot be utilized. This ensures that all captured CO2 is either used productively or stored safely, contributing to comprehensive carbon management strategies.
• Storage. Saline aquifers are directly involved in CO2 storage. They provide large, secure, and geographically widespread storage options for captured CO2. The storage process involves injecting CO2 into the porous rock formations, where it is trapped by the overlying impermeable rock layers (cap rock), preventing its escape and ensuring long-term containment.

Advantages:
Saline aquifers offer extensive storage capacity, making them a practical solution for large-scale CO2 storage. Their widespread availability enhances the feasibility of CCUS projects in various regions. The geological properties of saline aquifers, including their depth and cap rock integrity, provide secure and long-term storage options for CO2. Utilizing saline aquifers for CO2 storage supports international climate goals by providing a reliable method for sequestering captured CO2 and reducing greenhouse gas emissions.

Challenges:
Conducting comprehensive assessments to ensure the suitability and safety of saline aquifers for CO2 storage requires significant expertise, time, and resources. Ensuring that CO2 injection and storage processes are conducted safely and effectively necessitates robust monitoring and verification systems. Navigating the regulatory and administrative requirements for CO2 storage site approval necessitates careful planning and coordination. Addressing potential environmental and operational challenges associated with CO2 storage in saline aquifers is essential. Additionally, maintaining ongoing monitoring and verification of storage sites to ensure their integrity over the long term is crucial.

In summary, Saline Aquifers are underground layers of porous rock filled with saline water that provide a viable option for the long-term storage of captured CO2. In the context of Carbon Capture, Utilization, and Storage (CCUS), saline aquifers offer extensive and secure storage capacity, supporting comprehensive carbon management strategies. Despite challenges related to expertise, assessments, and regulatory compliance, saline aquifers are essential for advancing CCUS and achieving significant reductions in greenhouse gas emissions.