On September 4, 2024, the EPA announced it issued draft Class VI permits to Oxy Low Carbon Ventures LLC for three proposed wells to be dug for the geologic sequestration of carbon dioxide (CO2) in Ector County, Texas. These are the first draft permits the EPA has issued in Texas for Class VI wells under the Safe Drinking Water Act (SDWA) Underground Injection Control program, which establishes requirements to protect underground sources of drinking water from contamination.

 

These types of wells store CO2 captured from an emissions source or the atmosphere in deep underground wells. This project, located on former ranch land about 14 miles from the city of Odessa, includes three wells that will store about 722,000 metric tons of CO2 per year at a depth of about 4,400 feet.

“In developing the draft permit, EPA required the company to provide specific analysis of the site to ensure that constructing and operating the proposed wells remains protective of the environment, including preventing contamination to underground sources of drinking water and human-caused seismicity,” an Agency press release states. “EPA evaluated these technical analyses, with support from experts at the Department of Energy’s National Laboratories, and additional data to verify that the site’s geology, other nearby underground activity, and project scope and operations would ensure that the permitted activity meets [SDWA] requirements. EPA also required the company to ensure the plans are appropriate for conditions at and around the site, including construction materials, mechanical integrity and emergency response planning.

“Once permitted, Class VI wells require extensive monitoring for well integrity, ground water quality and CO2 movement. Well operators are also required to plan for emergencies and for how the well will be plugged after its lifespan. EPA also ensured the language in the draft permit is clear and enforceable under [SDWA] regulations. While developing the draft permit, EPA met with local elected officials and emergency responders, community members and property owners to explain the Class VI well program, listen to concerns and answer questions.”

The EPA has developed specific criteria under the SDWA to ensure underground sources of drinking water are protected from the CO2 stored in Class VI injection wells. Those criteria include:

• Site characterization requirements to ensure the geology in the project area can receive and contain the CO2 within the zone where it will be injected, including that the area is free of faults and fractures and that induced seismicity isn’t a concern. 
• Requirements to predict the extent of the injected CO2 plume and associated pressure front for the project using computational modeling and to identify and address any deficiencies of existing wells within the area of review through corrective action. The area of review includes the area where the injected plume and its associated pressure front may impact pore fluids.
• Well construction requirements to ensure the Class VI injection well is constructed in a manner that will prevent any CO2 from leaking outside of the injection zone. Class VI injection wells and in-zone monitoring wells are designed for the life of the project. Owners or operators must demonstrate that the well materials, including casing and cement, are corrosion-resistant and compatible with the conditions and fluids to which they may be exposed.
• Testing and monitoring requirements to monitor the integrity of the injection well, groundwater quality, and the movement of the CO2 plume and pressure front throughout the life of the project, including after CO2 injection has ended, until the permitting authority determines no additional monitoring is needed to ensure the geologic sequestration project doesn’t pose an endangerment to underground sources of drinking water (USDWs).
• Operating requirements to ensure the injection activity is appropriate for the well’s construction and geologic characteristics so it won’t endanger USDWs or human health.
• Requirements to plug the injection well in a manner that won’t allow fluid movement that endangers USDWs.
• Requirements for the operator to establish and maintain financial instruments sufficient to cover the cost of corrective action, plugging the injection well, post-injection site care, and emergency and remedial response for the geologic sequestration project (i.e., financial responsibility).
• Requirements to develop and maintain a site-specific emergency and remedial response plan.
• Requirements for the Class VI well owner or operator to report all testing and monitoring results to the permitting authority to ensure the project is operating in compliance with all permit and regulatory requirements. 

These injection wells—when used as part of carbon capture and storage (CCS) and CO2 removal (CDR) projects—are a critical tool for reducing carbon emissions to meet mid-century climate goals, according to the EPA.

“CO2 is injected through specially constructed wells that deposit and store material deep beneath the earth in rock formations,” the EPA news release adds. “These formations must be tested and evaluated to ensure that geologic formations are suitable for the safe containment of CO2 for long-term storage.  This technology will provide well-paying jobs and can be implemented in an environmentally responsible way.”