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The pore space race: Why the rapid development of geologic carbon storage is good for the climate

December 12, 2023 Work Area: Carbon Capture

The U.S. is laying the groundwork to prevent hundreds of millions of tons of carbon dioxide pollution from entering the atmosphere. The rapid acceleration of permit applications to store carbon dioxide in Class VI wells is proof that federal policies such as the Bipartisan Infrastructure Investment and Jobs Act (IIJA) and the Inflation Reduction Act (IRA) are catalyzing a major carbon capture industry in the U.S. Taken together, all of the wells underlying these permit applications would enable the storage of approximately 169 million metric tons of carbon dioxide per year, according to CATF’s internal analysis.1

What is a Class VI Well, and why does it matter for climate protection?

Class VI wells are those wells, as designated by the Environmental Protection Agency (EPA), where carbon dioxide can be stored deep underground in geologic formations. At these well sites, carbon dioxide is injected into rock formations thousands of feet below the Earth’s surface. These would-be emissions are then trapped permanently in the pore space of geologic formations, kept in place by impermeable rock layers that act as seals to prevent carbon dioxide from polluting the atmosphere and further heating the planet.  

How has policy accelerated efforts to sequester carbon dioxide?

Just two years ago, before passage of IIJA, there were only 22 Class VI well applications: 13 with the EPA and 9 with states that have primacy over Class VI wells.2 Today, the total number of wells with approved applications or applications under review has skyrocketed to 190. This includes 16 wells reviewed by states with Class VI primacy. In other words, there is a 1400% increase in potential future sites to permanently return carbon dioxide to the geosphere, rather than polluting the atmosphere.  

The acceleration of Class VI well applications demonstrates the effectiveness of 45Q enhancements in the IRA, particularly the increased credit value of $85 per ton of captured carbon sent to permanent geologic storage, to spur investment in geologic storage in the U.S. Further information about the geologic storage provisions and other recent carbon management policies can be found in CATF’s fact sheets on the IIJA and IRA.  

Carbon capture is working for the climate

Carbon capture is a well-established technology that is key to decarbonization of the power sector and critical industries like cement and steel manufacturing. However, until recently, the policies or sufficient incentives were not in place to promote its widespread adoption as a climate tool.  

In the U.S. today, over 80% of carbon capture projects that are under construction or already operational plan to use dedicated geologic storage.3 If fully realized, the projects with pending and approved Class VI applications could store eight times the amount of carbon dioxide that is captured today. This carbon dioxide will be stored thousands of feet underground, preventing it from entering the atmosphere and — crucially — from further heating the planet.  

EPA must accelerate its robust review of Class VI permit and primacy applications

Many large-scale carbon dioxide transportation and storage projects will need to be operating by 2030 for the U.S. to cut carbon pollution at the level needed to meet its climate targets. While it is encouraging to see a significant number of Class VI well applications across the country, the speed at which they are permitted and become operational is a crucial factor that controls their potential to benefit the climate. The prompt review of Class VI well applications is particularly important because proposed capture projects are often stalled while associated geologic storage permit applications are held up in review before EPA. The quicker Class VI wells are permitted and become operational, the greater the impact they will have. The Environmental Protection Agency (EPA) must ensure that it is devoting the resources needed to enable prompt and robust review of Class VI well applications, as well as state primacy applications, across all of its regions.  

A successful carbon management economy in the U.S. requires a suite of supportive infrastructure, from transportation networks including pipelines and Class VI wells to store carbon dioxide underground. As CATF’s analysis has shown, the higher 45Q credit level in the IRA has opened the door for more industries to abate their emissions using carbon capture, so there is a far greater demand for geologic storage of carbon dioxide. The acceleration of Class VI applications is encouraging, but the application review and permitting process must keep pace with this acceleration in order for the U.S. to reach its climate goals.  

EPA has already taken steps to accelerate its review of Class VI applications, but there remains a critical need for EPA to further streamline its processes. The IIJA increased funding for Class VI injection well permitting by $25 million between FY22 and FY26. These funds have supported additional full-time federal employees working on permit applications from just a handful to 25, distributed both at the national headquarters and at regional offices.4 EPA officials have committed to reviewing Class VI permits pending before them “as expeditiously as possible.”5 DOE also works with the National Laboratories to review subsurface modeling portions of permit applications.6 Building on these developments, EPA should aim to shorten the timeline for obtaining a construction permit from two years to one, aligning with the faster review timelines observed in states with Class VI primacy. This can most likely be achieved by shortening the timeframe of the technical review, which is expected to become more efficient over time through experience. 

New carbon capture project developers must also do their homework 

Carbon capture project developers pursuing Class VI well applications must play their part, too, by submitting complete and accurate application materials. Delayed permit decisions often stem from applications that are incomplete or lacking sufficient detail.vii When the EPA identifies gaps in permit applications, it communicates these shortfalls to the applicant and awaits the submission of the required additional information. This process of exchanging information can extend the time needed for permit review. The EPA advises developers to initiate early dialogue with their regional EPA office to mitigate such delays. This proactive approach helps applicants comprehensively understand the Class VI permit process and what the permitting authority requires. The EPA has also helpfully put together application templates for developers to follow.  

Managing the worst impacts of climate change will require building the right kind of infrastructure and building it quickly. Getting Class VI wells permitted and operational is a vital part of the overall decarbonization challenge that the U.S. faces. This will enable the power sector and industry to store the carbon dioxide they emit rather than polluting the atmosphere and heating the planet.  

Class VI Wells progress

Using CATF’s interactive map below, you can track all pending Class VI well applications, operating Class VI wells, and the Class VI primacy status by state. Click on each colored state to learn about the Class VI well applications and project information. The map shows where Class VI wells are planned around the country, and we will regularly update the map to reflect new applications as they are made available by EPA and states. 

1 Storage projections are based on available average single-well injection rates that EPA has published, which is limited to a handful of applications. Actual permitted injection rates for all pending wells will vary depending on geology and design. 

2 States with “primacy” for a given well class have primary responsibility for implementing the EPA’s Underground Injection Control program for that class. 

3 83% of all U.S projects with known storage plans based on the company’s own announcements. Some of these announcements have not yet led to a Class VI application. In total CATF is tracking 197 projects in the U.S. as of November 15, 2023. Of the 197 announced projects, 23 have yet to indicate their intention for carbon dioxide storage. 

4 Testimony of Mr. Bruno Pigott, Principal Deputy Assistant Administrator for Water U.S. Environmental Protection Agency: Hearing on Carbon Capture and Storage. Retrieved December 5, 2023, from 

5 Pigott, 2023 

6 Pigott, 2023 

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