(415f) A Phased Approach to Developing A Pipeline Network for CO2 Transport During Ccus

Stabilization of the levels of carbon dioxide (CO₂) in the atmosphere requires that the amount of CO₂ that is released by human activity (i.e., anthropogenic CO₂) must be reduced. A substantial majority of the anthropogenic CO₂ comes from the use of fossil fuels to provide energy. Maintaining the flow of energy is crucial to maintaining both the current quality of life and the global economy. Therefore, it is critical that methods for reducing the emission of CO₂ be developed, such as the use of alternative energy sources (e.g., nuclear or renewable fuels), improvements in energy efficiency, energy conservation methods, production of useful products from the CO₂, and permanent storage of the CO₂. Storage of CO₂ on a scale necessary to significantly reduce CO₂ emissions into the atmosphere from large stationary sources (such as power plants or industrial facilities) will require transport from the sources to the geologic formations via pipeline.

Because of the expense of capturing, compressing, transporting, and storing the CO₂, it is likely that some type of regulatory CO₂ emission limit will be required for implementation of geologic storage. The nature of the restrictions and their timing are unknown, but any limits would probably be phased in over a number of years. Such limits would provide the impetus for expanding the CO₂ transport infrastructure from the relatively few existing pipelines that have been constructed for specific CO₂-EOR needs.

Experts have identified several approaches to planning a future CO₂ pipeline network to support wide-scale carbon capture, utilization, and storage (CCUS) in the United States (Bliss et al., 2010). One approach consists of a nationwide network that could transport CO₂ to large-scale storage sites from geographically dispersed utility/industrial sources, much like the current natural gas network. A second approach employs regional pipeline networks that incorporate the existing pipelines that serve CO₂-EOR operations. A third approach is a series of smaller, discrete networks consisting of shorter pipelines from large power plant sources to nearby injection sites. Whichever model is ultimately selected, the pipeline network will probably be built in phases over the course of several years to meet the time line set by the regulatory drivers.

The Plains CO₂ Reduction (PCOR) Partnership has developed an approach that can be used to plan a CO₂ pipeline network that would be phased in over the course of several years. Various analogs for developing a pipeline network were identified and researched, including the natural gas network, the electricity distribution grid, and the U.S. interstate highway system. The information gathered during this research was used to identify an approach that could be used to develop a phased CO₂ pipeline network. The end result of this effort is a “how-to” manual that can be used to design a phased pipeline network.

It was assumed that the regulatory policies that would drive large-scale CCUS would be tied to stabilizing the atmospheric CO₂ concentration at either 450 or 550 ppm. Therefore, the amount of CO₂ that would need to be captured and stored in the PCOR Partnership region to meet these goals was determined for 2020, 2035, and 2050. The amount of CO₂ that reasonably could be available for sequestration from regional stationary source types was estimated for the same years based on past emission history and facility age. The source types that would likely be the first to implement CCUS were identified, and information about the storage capacities of the geologic sinks in the region was collected. This was done to identify the total pipeline capacity needed at each point in the future.

Both the emission sources and geologic sinks were mapped to identify clusters of sinks and sources at all three points in the future. A decision tree was developed to aid in identifying which clusters of sinks and sources should be connected and roughly at what point in the future. This was accomplished by ranking clusters of sources based on the expense associated with capture and compression for each future point in time. Geologic sink clusters were ranked based on the potential value of the CO₂ for that sink. The most profitable combinations of sources and sinks were linked with the shortest-distance pipelines. Trunk lines were connected and occasionally merged to form a network. The exercise continued until the pipeline network capacity matched the CO₂ available at that point in time. The cost of the pipeline network for that phase was estimated, and source–sink combinations and/or pipeline routes were adjusted to minimize the cost of the network for that phase of its development. Subsequent phases used the prior-phase network as a base.

The approach was put into practice during a case study in which a phased pipeline network was developed for the PCOR Partnership region. The methodology was refined based on the results of the case study to produce the best possible version of the approach.

Reference: Bliss, K., Eugene, D., Harms, R.W., Carrillo, V.G., Coddington, K., Moore, M., Harju, J., Jensen, M., Botnen, L., Marston, P., Louis, D., Melzer, S., Drechsel, C., Whitman, L., and Moody, J., IOGCC-SSEB CO₂ Pipeline Task Force members, 2010, A policy, legal, and regulatory evaluation of the feasibility of a national pipeline infrastructure for the transport and storage of carbon dioxide: Topical Report for Work Performed for Southern States Energy Board, Norcross, Georgia, December 2010.