Environmental risks and safeguards for CCS
Carbon capture and storage (CCS) carries potential environmental risks, but engineering practices, monitoring, and regulations aim to mitigate them. Understanding these risks helps guide safe deployment.
Primary risks
- Leakage from storage sites: if CO2 migrates out of the storage formation, it could return to the atmosphere or impact shallow groundwater. Proper site selection and impermeable cap rocks minimize this risk.
- Induced seismicity: injecting large volumes of CO2 can influence subsurface pressures and potentially trigger small earthquakes, especially if poorly managed.
- Groundwater impact: changes in subsurface chemistry from CO2-rich fluids could mobilize metals or alter water quality if CO2 reaches potable aquifers.
Operational risks
- Surface leaks and accidental releases: during transport, compression, or handling, leaks can occur; safety systems and emergency response plans are required.
- Ecosystem impacts: construction and pipelines can disrupt habitats, which calls for careful routing and mitigation measures.
Mitigation and safeguards
- Site characterization: thorough geological surveys ensure suitable storage formations with secure seals.
- Monitoring and verification: continuous monitoring of pressure, CO2 plume movement, and surface detection helps detect and address issues early.
- Regulatory frameworks: clear permitting, long-term liability allocation, and post-closure stewardship plans are needed.
- Best practices: controlled injection rates, pressure management, and emergency response reduce seismic and leakage risks.
Public perception and trust
Transparent communication, independent monitoring, and stakeholder engagement help build public confidence. Demonstration projects and rigorous regulation are essential to prove safety at scale.
Conclusion
While there are environmental risks associated with CCS, they are manageable with proper site selection, engineering, monitoring, and regulation. CCS can be deployed safely and offers a critical tool for reducing emissions from hard-to-abate sectors and achieving negative emissions when combined with biomass or direct air capture.