CGWA Comments on Proposed Federal Requirements for Carbon Dioxide Geologic Sequestration Projects

Proposed Rule – 73 FR 43492

CGWA provided comment on the US EPA’s proposed rule for deep geologic storage (GS) of Carbon Dioxide. The proposed rule, which would be implemented as part of the Underground Injection Control (UIC) program would govern many aspects of GS projects from initial permitting site studies through operator post-closure liability. While a promising technology for mitigation of CO₂ emissions, GS also has the potential to degrade underground sources of drinking water (USDWs). Even though deep injection of CO₂ has been used for decades years to enhance oil recovery, nothing on the scale of the proposed projects has been implemented.  A mid-sized Colorado power plant CO₂ sequestration project would inject about 5000 gpm for an anticipated 50 year project life and will have the potential to impact an area within a 50-mile radius. 

In development of the public comment document a CGWA ad-hoc committee mainly considered issues directly related to preventing degradation of groundwater resources. The committee developed and submitted an eight-page comment document requesting changes to the rule as it concerns the following issues:

1.      Mechanism for states to declare “sole-source” or otherwise “important” groundwater basins off limits to GS projects,

2.      Need to start projects at a small-scale,

3.      Consideration of aquifers with >10,000 mg/L TDS that may be used as USDWs,

4.      Need for further detail with respect to potential of induced earthquakes,

5.      Need for further consideration of CO₂ migration into USDWs,

6.      Need for additional detail regarding buffer zone monitoring wells,

7.      Need for additional consideration of the fate of brines displaced by CO_2,

8.      Risks associated with the presence of old wells in depleted oil and gas fields,

9.      Use of models to assess area of review,

10. Well construction and well conversion issues,

11. Post-closure operator liability,

12. Need for increased frequency of GS project reevaluation during first decade of project implementation,

13. Need to discuss mitigation options for large-scale failure of a mature GS reservoir.

Click here for the full CGWA comment document.

The CGWA would like to thank the following members for their participation and hard work:

• Andy Horn, CDM (Chair)
• Amy Hui, EKI Consult
• Mike Smith, CDM
• Chuck Norris, Geo-Hydro, Inc.
• Tom Dea, TZA Water Engineers
• Joe Meigs, Martin & Wood

The proposed rule as published in the Federal Register can be accessed via: http://www.epa.gov/fedrgstr/EPA-WATER/2008/July/Day-25/w16626.htm

EPA's web page on carbon sequestration can be accessed via: