(498f) Optimization of CO2 Pipeline Networks for Climate Change Mitigation

Over the last century, the United States has invested in an extensive network of wastewater collection systems to remove pathogens, dissolved organic matter, and industrial effluents from municipal wastewater streams. The investment secured a thousand-fold decrease in waterborne diseases and dramatically reduced fouling of surface waters from eutrophication. A comparable, nation-spanning investment is now needed to meet ambitious goals for arresting global climate change: namely, investment in gaseous pollutant collection systems to transport CO₂ recovered from major industrial sector greenhouse gas (GHG) emitters. Stabilizing the climate requires far more than electrifying automobile fleets and building wind and solar farms. Gigaton scale CO₂ capture, utilization, and storage (CCUS) is needed to cost-effectively achieve deeply decarbonized systems, e.g. 80% GHG emission reductions by 2050¹, and negative emissions systems, crucial to meet 1.5 degrees Celsius warming limits. Existing pipeline infrastructure is inadequate in scale and location to transport captured CO₂ from carbon-emitting heavy industries to geologic sinks and CO₂-utilizing manufacturers². Deployments of CO₂ capture and pipeline facilities are challenged by high capital costs, weak policy incentives for capturing CO₂, patchwork intra-state CO₂ pipeline laws, and an absence of federal authority over interstate CO₂ pipeline siting. Overcoming cost and pipeline siting regulatory constraints could significantly accelerate CCUS deployment.

Large industrial CO₂ sources by sector include refineries (188 Mt CO₂/yr), pulp and paper (143), iron and steel (83), petrochemicals (80), and cement (68). The CO₂ content in the exhaust gases from these sources also varies widely, with high fractions in ammonia, ethanol, and petrochemical plants (30-99.9+%) and medium to low concentrations from cement (14-33%), iron and steel (20-27%), and pulp and paper (8%) manufacturing³. The work requirement and the corresponding cost to separate CO₂ from the exhaust at purity suitable for pipeline transport varies in inverse proportion to the CO₂ content of the exhaust, ranging up to $70/ton CO₂ for capture from low concentration sources (e.g., natural gas power plants) using current state-of-art amine solvent capture technologies.

A sequential strategy is thus indicated for scaling industrial sector CCUS, with inexpensive near-term capture from industrial facilities that emit exhaust with high CO₂ content, followed by the addition of CO₂ from sources with progressively lower exhaust CO₂ concentrations, allowing time for the maturation of technology alternatives to amine scrubbing that may enable lower-cost CO₂ separation from dilute gas streams. Tandem to the sourcing considerations is the sale value of the captured CO₂ at its utilization site (or, in the case of carbon sequestration, the additional cost of CO₂ injection into a storage reservoir), as well as tariffs assessed to pipeline users for compression and transport of captured CO₂ from its industrial source to its intended endpoint. Presently the scale of CO₂ utilization is only 1% of total emissions, mostly for EOR operations in west Texas using CO₂ that is pipelined from natural underground reservoirs in New Mexico. Additional EOR operations, as well as expanded CO₂ utilization in other industries, are thought to be viable if CO₂ from anthropogenic sources is available for purchase at the typical oil-linked price of 40% of the per-barrel oil price per ton of CO₂. Investment in CO₂-dedicated pipeline infrastructure, financed in part or in whole by the government, can thus accelerate CCUS adoption to scales sufficient to alter the planet’s climate change trajectory by removing the “chicken-or-egg” barrier of linking large-scale CO₂ emission sources to CO₂ utilization or storage sinks.

In this presentation, we report on a methodology that was developed to optimize the sequential construction of CO₂ capture facilities and pipeline networks, to convey CO₂ from hard-to-decarbonize industrial processes to sites for CO₂ utilization as a feedstock. Capture costs and available CO₂ flow volumes from regional industrial emission sources in the Atlantic, Pacific, Midwest, and Southeastern U.S. were compiled from EPA datasets. Placement of trunk pipeline segments for aggregated CO₂ flows, within existing rights of way (e.g., corridors for natural gas pipelines, electricity transmission lines, interstate highways) was then determined using ArcGIS, and pipe diameters, lengths, and costs to build and operate pipeline networks connecting CO₂ sources to the trunk lines were calculated. Financial analysis was next conducted to determine the economic viability of pipeline networks of varying spatial extent and installation timetables under financing scenarios with partial and full government backing, taking into account pipeline tariffs, oil-linked CO₂ sale prices, availability of Section 45Q carbon sequestration credits, equity target internal rate of return, and technology advancements leading to lower future CO₂ capture costs.

A crucial systems interdependency of the CO₂ pipeline network is that the shared cost per unit flow in the pipeline increases as the flow volume decreases. The cost of CCUS abatement for one pipeline user is therefore dependent on the costs incurred by all other users on the same network, and whether or not those other prospective CO₂ “sellers” elect to use the pipeline system to bring their own CO₂ to market. The pipeline network is thus an inherently dynamic system, such that the financial analysis of the sized networks must be carried out iteratively until an economically viable network design is attained.

A case study is presented for the construction and operation of dedicated CO₂ pipeline network for the transport and delivery of captured carbon dioxide from industrial emitters along the Eastern seaboard of the United States to a terminal in Louisiana for enhanced oil recovery operations. Pipeline funding scenarios that involve full commercial financing, full government financing, and private-public partnership were investigated with the use of the Department of Energy's FE/NETL CO₂ Transport Cost Model. The range of capacity additions that are possible, beyond a baseline of 68 Mt CO₂/yr for full government financing of the pipeline, were explored for different technology advancement scenarios leading to a decrease in future onsite CO₂ capture costs.

1. Sustainable Development Solutions Network and the Institute for Sustainable Development and International Relations. Pathways to deep decarbonization. Deep Decarbonization Pathways Project (2015).
2. National Energy Technology Laboratory and the Great Plains Institute. Siting and Regulating Carbon Capture, Utilization and Storage Infrastructure. U.S. Department of Energy Workshop Report (2017).
3. P.C. Psarras, S. Comello, P. Bains, P. Charoensawadpong, S. Reichelstein, and J. Wilcox. Carbon Capture and Utilization in the Industrial Sector. Environmental Science and Technology (2017) 51, 11440-11449.