Site Selection

What goes into selecting a carbon capture and storage site?

When most people think about carbon dioxide (CO₂) capture and storage sites, they tend to think they are at one location; however, the sites where CO₂ is captured and where it is stored are often in different locations. There are many industries that are ideal for carbon capture, including power generation, metals refining, oil and gas refining, cement production, and chemical manufacturing because they make up almost one quarter of CO₂ emissions in the country and can be among the hardest to abate.

To get the captured CO₂ to a safe storage site, it must be transported via pipelines or trucks. Suggested options for doing so in the northeast are discussed in the Infrastructure Options section. The safe storage of CO₂ in rock formations deep underground depends on proper site selection and care. The first step of any potential CCS project is the characterization phase, which is a detailed analysis of potential sites to ensure safe, secure, and permanent CO₂ storage. It is also critical that the stored CO₂ will not affect underground sources of drinking water (USDWs) or negatively impact any communities near the site.

Potential Carbon Capture and Storage in the Northeast and Offshore

The team of geologists and engineers working on EXPLORE ACS have identified optimal scenarios for capturing CO₂, transporting it, and storing it offshore. The team’s recommendations come from detailed analyses of geological data of the subsurface offshore, existing infrastructure and opportunities for expansion, and ideal locations for capturing industrial emissions. This is done while keeping the protection of land and the existing tourism industry top of mind to ensure both can co-exist in the space.

Screening appropriate storage sites is a critical first step. An ideal site must have layers of rock within the subsurface with sufficient empty space to contain enough CO₂ to meet project goals. CO₂ is buoyant in the subsurface, so it is critical that the storage reservoir, a location beneath the surface where the captured CO₂ is stored, is below effective caprocks, preventing the CO₂ from leaving the reservoir and migrating upward. Finally, the storage reservoir must have sufficient depth to keep the CO₂ in a liquid-like state, known as a “supercritical state,” which maximizes the volume of CO₂ that can be held in the reservoir.

The EXPLORE ACS team utilized a process called “common risk segment” (CRS) mapping, which maps out three components of the analysis: subsurface, cost, and operational restrictions.

Subsurface: The technical aspects of the rocks themselves.
Cost: The relative cost to develop an offshore storage site.
Operational Restrictions: The environmental, logistical, and governmental factors that impact access to the offshore site.

These maps are then combined to produce a final assessment of the area’s storage potential. The final composite CRS map, combining the three risk segment maps, is shown below.

Summary view of the CRS-mapping procedure to help rank candidate sites

If the subsurface meets the ideal criteria, the next step is to create a 3D digital representation of the rocks called a “static earth model,” which contains key parameters controlling how the CO₂ and rocks interact in the subsurface. Upon completion, this model is used to simulate the behavior of injected CO₂ over the project lifespan, providing estimates of the volumes that can be injected, where the stored CO₂ would be expected to travel within the storage reservoir, pressure changes expected in the reservoir, and many other insights. The following map summarizes the team’s findings in more detail.

3D view of a static earth model at one of the candidate storage sites

Infrastructure Options

Infrastructure Options

CO₂ Transport

The EXPLORE ACS team identified pipeline routes that are viable for transporting captured CO₂ from major emissions hotspots. These potential routes were identified using a combination of existing infrastructure and infrastructure that could be newly developed to support an offshore CCS hub. The map to the left shows a potential roadmap for pipeline configuration in the region.

The above map summarizes potential options for CO₂ transport and storage in the region.

CO₂ Storage

The primary considerations for offshore carbon storage infrastructure are whether subsea or surface equipment will be used. For subsea equipment, the wellhead will rest on the seabed. For surface equipment, the wellhead sits on a platform that can range from 33 meters tall to 160 meters tall depending on the depth of the water. When considering what type of equipment to deploy, factors such as development costs, maintenance, and visual impact are important to acknowledge.

Diagram depicts a possible option for injecting CO₂ via surface equipment. Diagram depicting offshore CO₂ storage infrastructure options supplied by Aker Solutions.

Diagram depicts a possible option for injecting CO₂ via subsea equipment. Diagram depicting offshore CO₂ storage infrastructure options supplied by Aker Solutions.

Field Development

Different field development options can be utilized depending on the type of equipment used, which makes every CCS project a unique undertaking.

Daisy Chain

In a daisy chain, wells are connected to the main pipeline following ideal well locations.

Template Network

In a template network, wells are located in clusters within template structures or in close proximity to manifolds.

Gather & Distribution + Sattelite Wells

In this configuration, the main pipeline is connected to distribution hubs, which direct the flow of CO₂ to connected wells.

Diagrams depicting field development options supplied by Aker Solutions.

Community Integration

Community Engagement

To ensure a successful capture, transport, or storage project, well-timed and ongoing stakeholder engagement is encouraged. Good engagement happens before, during, and after a CCS project to ensure long-term support and interest from the areas in which these projects are sited and in those same communities by the companies implementing them.

Workforce Development

CCS stimulates workforce development with the creation of new jobs and the opportunity to advance careers through CCS-specific training. Working with technical and training centers to learn more about CCS and the skills needed to run an operation helps advance both the education and industry sectors. Additionally, it will also benefit workforce development by offering apprenticeship programs and promoting new job opportunities for people starting their careers.