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Introduction and Scope

1.1 STUDY CONTEXT

As one essential component of maintaining a stable, safe climate, the world must transition to a net-zero, or even net-negative, carbon emissions¹ system, in which there is no net accumulation of carbon dioxide (CO₂) in the atmosphere. According to the Intergovernmental Panel on Climate Change 2022 report on climate change, global net anthropogenic greenhouse gas (GHG) emissions continued to rise and reached 59 ± 6.6 Gt CO₂e (gigatonnes of carbon dioxide equivalents) in 2019, although the rate of growth has fallen compared to the previous decade (IPCC 2022). Nonetheless, annual average emissions levels were higher between 2010 and 2019 than during any other time in human history. CO₂ emissions from fossil-fuel combustion and industry account for the largest percentage of GHG emissions (64 percent in 2019) and the largest absolute emissions growth since 1990 (67 percent). If global CO₂ emissions continue at current rates, models indicate that the world will exhaust the remaining carbon budget for limiting warming to 1.5°C before 2030, and before mid-century for limiting warming below 2°C (MCC 2022). Reducing reliance on fossil resources and mitigating GHG emissions would have co-benefits beyond limiting global warming, such as improving air quality by reducing criteria pollutants. The COVID-19 pandemic initially caused a global economic slowdown and corresponding decline in anthropogenic CO₂ emissions, most notably in the transportation sector. While most economies and emissions have already rebounded and even surpassed previous annual levels (IEA 2021), the long-term effect of the COVID-19 pandemic on anthropogenic emissions remains uncertain. Some behavioral changes from the COVID-19 pandemic, such as increased remote work and less business travel, could translate to a reduction in GHG emissions. Halting and ultimately reversing climate change will require more than behavior change, however. It will require net-zero or net-negative emissions over prolonged periods of time, fueled by large capital investments in innovative technologies.

Such a transition is challenging for many reasons, including that living things are carbon based, and carbon-containing manufactured products—such as fuels, building materials, plastics, and commodity chemicals—pervade the modern world. Currently, these products are derived primarily from fossil carbon, including coal, oil, and natural gas, and their production, use, and disposal typically result in accumulation of CO₂ in the atmosphere. Net-zero

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¹ Net-zero carbon emissions is shorthand for net-zero greenhouse gas (GHG) emissions. The bulk of GHG emissions by volume is CO₂, with other GHG emissions often expressed in terms of equivalent amounts of carbon or CO₂. This study examines CO₂ utilization specifically, and thus, the committee will refer to net-zero CO₂ emissions and will discuss primarily volumes and masses of CO₂ emissions. Other GHGs are not considered in depth in this report, though they also must be addressed, in conjunction with CO₂ emissions, to reach a stable climate system. Throughout the report, net-zero CO₂ emissions are referred to as “net-zero.”

systems do not require the entire elimination of carbon-based products and systems, or their CO₂ emissions, but they do require that flows of CO₂ to and from the atmosphere be balanced across total sources and sinks. Requiring net-zero CO₂ emissions will mean a significant reduction in many flows of carbon in the Earth system. For example, much gasoline and diesel fuel use for transportation will be eliminated in favor of clean electricity or hydrogen. For those uses of carbon-containing products that cannot be eliminated, the resulting CO₂ emissions will need to be balanced by diverting CO₂ from entering the atmosphere or removing CO₂ directly from the atmosphere.² Where needs for carbon-based materials remain, carbon wastes,³ including CO₂ waste streams, can play a role as feedstocks for products. To put these needs into context, Box 1-1 highlights several studies examining the role of carbon capture, utilization, and storage (CCUS) in achieving net-zero emissions by 2050. This report focuses on CO₂ utilization, in which CO₂ feedstocks replace fossil-carbon feedstocks to help enable continued production, use, and disposal of carbon-based materials in a net-zero world with balanced flows of CO₂ to and from the atmosphere.⁴ Sustainable CO₂ flows are illustrated in Figure 1-1.

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² Pathways for removing and sequestering CO₂ directly from the atmosphere, including direct air capture with sequestration, coastal carbon sequestration, and carbon uptake by forests and soils, are detailed in a 2019 National Academies report on Negative Emissions Technologies and Reliable Sequestration (NASEM 2019). Such negative emissions technologies are not the focus of this report. That National Academies report and others address the scale at which these solutions can be deployed and their projected effectiveness in meeting net-zero emissions targets (see, e.g., Carbon180 2022; EASAC 2018; EFI 2019; Mulligan et al. 2020).

³ For the purposes of this report, carbon wastes are limited to CO₂ waste streams. A second report of the committee will also address coal-derived carbon wastes. Other non-CO₂ waste streams, including methane, biogas, plastic waste, used carbon-based products, and bio-based carbon feedstocks such as biomass and municipal, sanitary, and agricultural wastes, are outside the scope of the study.

⁴ As further discussed in Box 1-2, CO₂ utilization for the purposes of this report is defined as a chemical transformation of CO₂ and therefore does not include enhanced oil recovery.

CO₂ utilization may be an important part of a future net-zero world, but there are many challenges to its use at large scale today. For the CO₂ utilization opportunities within the scope of this study (i.e., chemical transformations of CO₂, see Box 1-2 for details), few commercial processes exist as of 2022, and those that exist are performed at limited scale. There are many challenges to commercializing CO₂ utilization processes, including (1) the inherent difficulty, given the thermodynamic stability of CO₂, of transforming it into desired products, relative to using fossil-carbon feedstocks to synthesize the same product; (2) the lack of infrastructure to enable CO₂ utilization at a large scale for purposes other than enhanced oil recovery (EOR); (3) the need for inputs of clean (i.e., low- or zero-carbon)⁵ hydrogen, electricity, and heat; and (4) the resulting higher cost of CO₂-derived products compared to alternative products. Discovering, developing, and commercializing CO₂ utilization processes and products are important activities for the nation and the world as it transitions to a net-zero economy. In response to this need, the Consolidated Appropriations Act of 2021, including the Energy Act of 2020, legislated a mandate for the U.S. Department of Energy (DOE) to enter into an agreement with the National Academies to conduct a study “to assess any barriers and opportunities relating to commercializing carbon, coal-derived carbon,⁶ and carbon dioxide in the United States” (Consolidated Appropriations Act 2021). The mandate further required study of CO₂ utilization markets, infrastructure, and research, development, and deployment. The study statement of task is reproduced at the end of this chapter.

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⁵ “Clean” or low- or zero-carbon refers to the CO₂ emissions associated with the input (e.g., hydrogen, electricity, or heat), which depend on the methods by which it is produced. The committee follows DOE’s definition and therefore defines clean hydrogen as having a GHG footprint of less than 2 kg CO₂e per kg H₂.

⁶ Coal-derived carbon will be examined in the second report of the study.

Per its statement of task, the study will produce two reports, with this first report focusing on the current state of infrastructure for CO₂ transportation, use, and storage in the United States, as well as priority opportunities and challenges to develop that infrastructure to enable future CO₂ utilization processes and markets in a safe, cost-effective, and environmentally benign manner. The second report will evaluate in more detail the potential markets for products derived from CO₂ and coal waste; the economic, environmental, and climate impacts of CO₂ utilization infrastructure; and research, development, and demonstration needs to enable commercialization of CO₂ utilization technologies and processes. In addressing the first report’s tasking, the committee first considered which products and processes are required for, or could contribute to, a future net-zero economy. Then, for those products and processes, the committee evaluated the associated infrastructure requirements, including for CO₂ and/or product transportation, CO₂ conversion, and other necessary inputs such as clean hydrogen and clean electricity. (See Box 1-2 for more detail about the definition and scope of CO₂ utilization used in this study.) The committee considered opportunities and challenges for the policy, regulatory, and societal aspects of developing CO₂ utilization systems. Key topics addressed in the report are introduced below.

1.2 OVERVIEW OF CO₂ UTILIZATION PRODUCTS, INFRASTRUCTURE, AND SOCIETAL CONSIDERATIONS

The following sections provide background on the potential future demand for CO₂ utilization products in a net-zero system; infrastructure for CO₂ capture, transport, utilization, and storage; and current policies, regulations, and economic and societal considerations for CO₂ utilization. Box 1-3 examines the role of life cycle assessment and product lifetime in assessing the CO₂ emissions impact of a CO₂ utilization product.

1.2.1 Demand for CO₂ Utilization Products in Net-Zero Systems

CO₂ utilization will perform two key roles in future net-zero systems: serving as a feedstock for manufacturing carbon-based products sustainably, as well as storing carbon in solid form in durable products, sequestering it from the atmosphere for climate-relevant timescales. Key product categories, examined in Chapter 3, include construction materials (concrete and aggregates), chemicals and fuels (single- and multi-carbon molecules), polymers and polymer precursors, elemental carbon materials, and niche products. These processes require sources of CO₂, which can be collected from a diverse array of emitting facilities with various concentrations, impurities, and CO₂ volumes, or from the vast but low-concentration resources in the atmosphere and bodies of water. Further explored in Box 1-3 and Figure 1-3-1, long-lived CO₂-based products (so-called Track 1 products, with carbon storage of >100 years) offer opportunities for durable CO₂ storage, while shorter-lived products (Track 2, carbon storage of <100 years) can be enablers of a circular carbon economy to ensure continued access to essential carbon-containing products (Sick et al. 2022). The production and use of these two respective product types therefore will have different climate impact for each CO₂ molecule used. CO₂ utilization complements alternative sustainable sources of carbon, including product recycling and biomass, as well as alternative ways to meet societal needs, for example, using electricity or hydrogen as energy carriers in lieu of hydrocarbon fuels. Rigorous and transparent life cycle assessments that follow harmonized approaches provide the basis for decision making and reporting at every stage of research, development, and deployment.

1.2.2 Infrastructure for CO₂ Capture, Transport, Use, and Storage

Infrastructure to enable production and use of carbon-based products in a circular carbon economy includes technologies for CO₂ capture, methods to transport CO₂ and/or CO₂-derived products, facilities and technologies to transform CO₂ into useful products, and reservoirs for geologic CO₂ storage. CO₂ can be captured from point sources such as power plants and industrial facilities, from the atmosphere through direct air capture (DAC), or from the ocean and other bodies of water containing dissolved CO₂. Chapter 2 provides details about potential sources of CO₂ for utilization in the United States. Once the CO₂ has been captured, it can be chemically transformed on-site into a valuable product, transported for utilization elsewhere, or transported for long-term geologic storage. The primary mode of transportation for CO₂ is via pipeline, which can accommodate large volumes and involves transporting CO₂ primarily in its supercritical fluid state. Other transportation methods, which typically transport CO₂ in its liquid state, include truck, rail, ship, and barge. Chapter 2 provides more information about the status of CO₂ transport by each of these methods in the United States. As detailed in Chapter 4, in some cases, a combination of transport modes could be the optimal solution to move CO₂ from the source to the point of storage or use; in other cases, it may be desirable to utilize CO₂ at the point of capture and transport the CO₂-derived product instead.

As discussed in Chapter 2, several current CO₂ utilization processes transform CO₂ into a useful product, the largest of which is the synthesis of urea. Other smaller-scale commercial processes include synthesis of salicylic acid, methanol, and organic carbonates. Emerging facilities that co-locate sustainable CO₂ capture and utilization are currently in operation in the United States or worldwide (see, e.g., Circular Carbon Network 2022). For production of chemicals, examples include Carbon Recycling International’s renewable methanol plant in Iceland, which has been operating since 2012 and produces 4,000 tons of methanol per year from CO₂, and two facilities in China that have partnered with LanzaTech on biological CO₂ conversion to commodity chemicals (CRI n.d.;

McCoy 2022). Both Carbon Recycling International and LanzaTech have additional projects under development or construction worldwide. For mineralization examples, there are a growing number of companies that provide CO₂-cured ready-mix concrete for commercial projects (CarbonCure 2022). The 2021 IIJA authorized funding across the CO₂ capture, transportation, use, and storage value chain, including $2.1 billion for CO₂ Transportation Infrastructure Finance and Innovation (§ 40304), $310 million for the Carbon Utilization Program (§ 40302), and $3.5 billion for establishing four regional DAC hubs (§ 40308) (IIJA 2021).

Although long-term geologic storage of CO₂ is not a focus of this report, it is still critical to consider when planning infrastructure development for CO₂ utilization, as explained in Chapter 4. The main geological formations being considered for CO₂ storage are saline reservoirs, depleted oil and gas reservoirs, and unmineable coal seams (Jones and Lawson 2021). Figure 1-2 illustrates the locations of these geologic reservoirs in relation to CO₂ pipelines, power plants, and other point-source emitters. Within the context of the existing infrastructure for CCUS and other enabling industries (e.g., hydrogen, clean electricity, and water), Chapters 4 and 6 present considerations and opportunities for further CO₂ utilization infrastructure development.

1.2.3 Societal Considerations, Including Environmental Justice, Public Acceptance, and Policy and Economic Issues

In addition to the scientific and engineering considerations for developing technologies and infrastructure, various socioeconomic factors must be taken into account for successful deployment of CO₂ utilization. Economic, policy, regulatory, and community engagement tools exist that, when strategically implemented with incorporation of environmental justice principles, can facilitate both individual projects and the development of a widespread CO₂ utilization industry. Certain incentives can enable emerging technologies to compete with incumbent products and processes and encourage knowledge spillover, that is, the creation and sharing of information and best practices, to accelerate growth of this nascent industry. At an individual project level, navigating the regulatory framework and permitting processes, in addition to securing societal acceptance, is crucial for project success. Meaningful community engagement is important to ensure equitable distribution of the harms, benefits, and risks of these projects as these technologies are implemented for a more sustainable future. Chapter 5 expands on these socioeconomic tools.

1.3 STUDY STATEMENT OF TASK

The report that follows is the first of two reports produced by the Committee on Carbon Utilization Infrastructure, Markets, Research and Development. This first report focuses on the current state of infrastructure for CO₂ transportation, use, and storage, and priority opportunities to develop, improve, and expand that infrastructure to enable carbon utilization. The full study statement of task is as follows:

1. Infrastructure
   1. Building off the study’s first report, assess infrastructure updates needed to enable safe and reliable carbon dioxide transportation, use, and storage for carbon utilization purposes. Assessment of infrastructure will consider how carbon utilization fits into larger carbon capture and sequestration infrastructure needs and opportunities;
   2. Describe the economic, climate, and environmental impacts of any well-integrated national carbon dioxide pipeline system as applied for carbon utilization purposes, including suggestions for policies that could: (i) improve the economic impact of the system; and (ii) mitigate climate and environmental impacts of the system.
2. Research, Development, and Demonstration
   1. Identify and assess the progress of emerging technologies and approaches for carbon utilization that may play an important role in a circular carbon economy, as relevant to markets determined in section 1a.
   2. Assess research efforts under way to address barriers to commercialization of carbon utilization technology, including basic, applied, engineering, and computational research efforts, and identify gaps in the research efforts;
   3. Update the 2019 National Academies comprehensive research agenda on needs and opportunities for carbon utilization technology RD&D, focusing on needs and opportunities important to commercializing products that may contribute to a net zero carbon future.

The first and second reports will provide guidance to infrastructure funders, planners, and developers and to research sponsors, as well as research communities in academia and industry, regarding key challenges needed to advance the infrastructure, market, science, and engineering required to enable carbon utilization relevant for a circular carbon economy.

1.4 REFERENCES