Sealing Cap: Above the porous rock, there must be an impermeable layer (often made of clay or shale) that acts as a "cap rock," preventing CO₂ from migrating upward and escaping to the surface.
The monitoring of these deep underground formations is crucial to ensure the CO₂ remains securely stored over time. Continuous monitoring involves using seismic imaging, pressure sensors, and other technologies to detect any potential leaks or shifts in the storage site, ensuring long-term safety and efficacy. As of now, several pilot projects and commercial-scale storage sites are being operated worldwide, and while the technology is promising, large-scale deployment of CCUS and storage in deep underground rock formations still faces challenges related to cost, regulation, and public perception. However, these storage solutions are considered an essential component of global efforts to achieve net-zero emissions and combat climate change.