For geological carbon sequestration to work, we need a geospatial planning policy

According to the Intergovernmental Panel on Climate Change, the world will not reach net zero emissions unless we find a way to capture and inject enormous quantities of carbon dioxide underground. To do its part, the United States alone will need to store 0.7 to 1 gigatons of CO₂ annually from 2020 through 2050—mostly in giant saline aquifers that span the porous subsurface.

In 2014, the SaskPower project at the Boundary Dam Power Station near Estevan in Saskatchewan, Canada, became the first large power station in the world to successfully use carbon capture and storage. The project remains active. Image credit: Anne Menefee (Pennsylvania State University).

Trapping, transporting, and pumping millions of tons of carbon dioxide underground in an affordable way is a significant technical challenge. Dozens of carbon capture and storage projects are in various stages of planning and development in the United States, ranging from power stations and industrial facilities to ethanol plants. Government incentives will help—Congress expanded the 45Q tax credit via the 2022 Inflation Reduction Act, which reduces the cost and financial risk of starting such projects. Anticipating a boom, private companies are leasing the rights to suitable storage sites underground as part of deals that are separate from the more conventional land and property deals on the surface (1).

These efforts are necessary, but not sufficient to make geological carbon sequestration (GCS) a reality at the required scale. The United States needs a coordinated approach to the associated bureaucracy and paperwork to include planning, regulation, property rights, and liability (2, 3). We argue for such a system here and suggest how it could work.

Deep Storage

The tiny pores in rock that GCS advocates prize for their carbon-trapping qualities are increasingly in demand. At various depths, subsurface pore space is already used to store natural gas (more than 130 billion cubic meters of underground capacity) (4), dispose of wastewater (more than 712,000 wells) (5), keep drinking water for use during droughts (6), generate geothermal energy, and hold helium (7), among other uses. There is also growing interest in using porous reservoirs for underground energy storage, in the form of hydrogen or compressed air (Fig. 1A).

Fig. 1.

Conflicts between GCS and other subsurface activities. (A) Schematic illustration of complexities in subsurface energy planning and coordination among surface and subsurface (including vertical and aerial extent) applications. (B) Insets illustrate examples of potential conflicts among subsurface uses, including (Upper) competition among different uses or demands for the same reservoirs within a given basin [e.g., GCS and underground hydrogen storage (UHS)], and (Lower) vertical competition that would necessitate drilling into formations above or below an existing subsurface energy operation and pose additional risk. Image credit: Seth Blumsack (Pennsylvania State University).

Combined with existing oil, gas, and mining projects, this all adds up to an already-complicated and often-conflicting series of demands and uses of the deep subsurface. And because GCS will generally aim to use very deep underground formations, it’s often impossible to deploy without working close to or directly below other tunnels, pipes, equipment, and stored materials.

To resolve such “vertical conflicts,” some permitting regimes allow subsurface activities only at specific depths to avoid pollution of substances at other depths, such as the Environmental Protection Agency’s Underground Injection Control program, which strives to prevent the contamination of groundwater. And some state regulations do address some potential competing uses. But, as it stands, there is no comprehensive subsurface management approach of the kind that is needed to ensure the smooth expansion of GCS.

That’s a problem because industry needs legal certainty over the use of pore space across four dimensions—horizontally across a given reservoir, vertically across subsurface layers, communication between subsurface and surface land use, and evolving subsurface uses over time.

Without an up-front mapping and evaluation of current and future subsurface activities, including consideration of the pores most suited to specific uses and regulation that spatially and temporally allocates uses, acquisition and use of the subsurface will be conflict-ridden and inefficient. However, such a use-based mapping and allocation effort is not straightforward and also requires consideration of surface uses.

Some subsurface uses of pore space benefit from geographic proximity to surface uses; for example, natural gas storage is ideally located near the populations and power plants that need natural gas during weather extremes. With respect to time, in some cases, it may be most efficient to complete existing or planned oil and gas development within a formation before using the depleted formation for storage of CO₂ or other substances.

A Lack of Laws

There is little public law to comprehensively guide subsurface planning or resolve vertical or horizontal disputes among different subsurface owners, including those that could evolve over time and those that could also involve surface–subsurface conflicts. States such as West Virginia and Wyoming have enacted statutes that define pore space ownership and, in limited circumstances, allow for forced pooling of pore space for GCS if a minimum percentage of reservoir owners agree. States including Louisiana have begun to define liability for CO₂ leakage. And states such as West Virginia and North Dakota allow oil and gas operators to drill down through GCS operations if the operators follow regulations designed to preserve the integrity of the GCS operation.

Despite these and other legislative and regulatory efforts, no states have yet fully addressed how to efficiently allocate subsurface space to competing users or how to mediate conflicts.

Such conflicts are likely to emerge from the pressure fronts associated with supercritical CO₂ injection and displacement of resident brines, which are complicated to predict, given the uncertainties associated with CO₂ plume migration in most projects (8). Managing pressure fronts and maintaining reservoirs below critical fracture pressures will often require brine extraction, creating additional demands for wastewater management or disposal (9, 10).

These issues cannot be addressed at the state level alone. Many suitable storage sites span several states, and even when they do not, it’s possible that injecting carbon dioxide deep underground will produce pressure fronts that cross state lines. Also, most companies involved in GCS will have operations in multiple states; navigating different regulations adds complexity and costs. Deployment of the technology will be more effective if regulatory and legal aspects are streamlined and consistent.

To achieve this, the federal government can and ought to take a more active role in coordinating regional uses of the subsurface. There is precedent here. Federal leadership in land planning dates back to 1921, when then-Secretary of Commerce Herbert Hoover appointed a federal commission to write and recommend a Standard State Zoning Enabling Act for local government planning and regulation, which all 50 states ultimately adopted in some form. This effort led to thousands of local comprehensive plans and zoning codes to regulate land use (11).

Calling for a Commission

A similar commission could now provide guidance for GCS. We call for the creation of such a commission within the Department of Energy (DOE). The DOE would be the appropriate host, given the agency’s history of funding GCS research and establishing the Regional Carbon Sequestration Partnerships that conducted foundational research for carbon capture and storage projects across the United States from 2003 through 2019.

This new “Commission on Subsurface Energy Planning” would have two main jobs. First, it would oversee the mapping and assessment of existing and projected subsurface uses, along with overlapping uses beyond GCS, such as energy storage and geothermal energy development. This mapping effort should specify the depths and potential extents of existing and potential subsurface uses and visually depict potential conflicts across time and spatial scales. Second, the commission should recommend protocols to avoid and resolve conflicts.

If we are serious about the role of GCS in addressing the climate crisis, it is time for US policy makers to properly and strategically address subsurface resource management.

The commission need not tell states what to do. Instead, it would steer GCS development through a series of new regional subsurface planning groups formed by states. This would enable a comprehensive, national, unified approach to planning that allows for regional geographic and political differences. And, if implemented well, the commission would guide and plan for GCS and other subsurface uses in a way that reduces conflict and speeds up development, rather than adding more red tape. Indeed, we’re not suggesting that any approval of pending subsurface activities be delayed while the commission and regional groups are formed, but rather, that this new subsurface planning process guide subsurface uses as soon as is feasible.

The regional groups acting beneath the commission would formalize and implement plans and regulations of subsurface use, based on questions such as how the subsurface is currently being used and how that might change in the future. The groups would then assess and set out a way to mitigate potential conflicts, based on local context, along with energy and environmental goals.

This type of regional subsurface planning could match efforts that are beginning to form at the regional level to coordinate surface activity, such as plans for networks of CO₂ pipelines or regional hydrogen hubs. This federal–regional structure would also emulate the way the electricity industry plans transmission networks and sets reliability standards, or how regional river basin commissions collectively regulate water use and water quality (12).

This would be a new approach to subsurface energy planning, but in some ways analogous to marine spatial plans (MSPs) already used or in progress in more than 125 countries (13) to coordinate the use of a vast space by diverse stakeholders over time. MSPs engage often-conflicting groups to map, plan, and regulate a large number of competing or overlapping uses of the ocean on a large scale (14). They are highly adaptive and designed to be frequently revisited and updated, which is essential for large expanses of space with numerous, diverse, and shifting uses (15). Many of the tools that have been applied in marine spatial planning can and should be transferred to US regional and national planning efforts for GCS.

To ensure adequate expertise and broad representation of public and industry interests, the DOE should select members of the commission with diverse backgrounds. These could include climate and citizen groups, scientific experts from universities and national laboratories, energy companies, and state and local governments. Members should also be drawn from relevant federal agencies and units, including the US Geological Survey, the Environmental Protection Agency, the Department of Interior, and the DOE’s own Office of Fossil Energy and Carbon Management. The regional groups, in particular, will need expertise in geosciences and subsurface engineering to recommend pore space allocation based on the suitability of sites for different purposes.

Once established, the commission’s first task would be to determine the regional boundaries for spatial subsurface planning. These would likely be based on assessment of high-capacity geologic basins; surface-level energy and emission management systems that need ties to different subsurface resources; and existing or foreseen pipeline routes to connect these surface demands with available pore space.

The commission will also need to reach an expert-informed consensus on the best mechanism to establish and update subsurface use allocation plans set out by the regional groups, as well as protocols on how the regional groups should be governed. One option is to make the groups loosely analogous to regional river basin commissions, to encourage planning criteria based on existing and potential future subsurface uses in different regions.

The commission would also need to consider what new information or knowledge might require changes to regional boundaries and ways for boundaries to be redrawn in line with subsurface resource development and legal revisions.

In addition, subsurface spatial management plans should consider the future of carbon capture technology, since the points of CO₂ capture will influence transport requirements and, thus, the economics of GCS. Subsurface planning requirements are much different for a world in which CO₂ is captured from large point sources and moved to centralized GCS facilities than a world in which GCS predominantly relies on direct air capture of CO₂ from any location.

In summary, governments and companies need a dedicated plan to prevent the necessary development of GCS in the United States from being delayed or derailed by conflict, uncertainty, and case-by-case resolution of such conflict. Competition for pore space and supporting surface space is likely to become a growing issue in some regions, both among subsurface uses that span large aerial footprints and among multiple surface needs, such as wellheads and associated construction equipment, to access the same subsurface pore space. The many dimensions of subsurface management collectively complicate this issue and necessitate adaptive planning, as conflicts must be avoided both geospatially and vertically over extended time frames. If we are serious about the role of GCS in addressing the climate crisis, it is time for US policy makers to properly and strategically address subsurface resource management.