First published in Cornerstone, Volume 4, Issue 4
By Janet Gellici, Chief Executive Officer, National Coal Council
Consensus is growing among industry, the environmental community, and international governments that future carbon dioxide (CO) emission reduction goals cannot be met by renewable energy alone and that carbon capture, utilization, and storage (CCUS) technologies for all fossil fuels must be deployed to achieve climate objectives in the U.S. and globally. Fossil fuels—including coal, natural gas, and oil—will remain the dominant global energy source well into the future by virtue of their abundance, supply security, and affordability.
Achieving global climate objectives will require a portfolio of approaches that balance economic realities, energy security, and environmental aspirations. The most influential action the U.S. can employ to reduce COemissions is to incentivize the rapid deployment of CCUS technologies. CO utilization can, in theory, help to reduce CCUS costs and incentivize deployment, but most CO use technologies face numerous and significant challenges in moving toward commercialization.
Geological COutilization options have the greatest potential to advance CCUS by creating market demand for anthropogenic CO . The use of CO for enhanced oil recovery (CO -EOR), including production and storage activities in residual oil zones (ROZ), remains the CO use technology with the greatest potential to incentivize CCUS.
Non-geological COutilization options are unlikely to significantly incentivize CCUS in the near to intermediate term because of technical, greenhouse gas (GHG) life-cycle analysis (LCA) considerations, and challenges associated with scalability. Despite these barriers, further investments in non-geologic CO utilization technologies may, on a case-by-case basis, hold promise for turning an uneconomic CCUS project into an economic one. A broadly deployed mix of CO utilization technologies may help advance CCUS deployment incrementally, providing sufficient incentive to keep CCUS technologies moving forward.
NATIONAL COAL COUNCIL MISSION
The National Coal Council (NCC) is a federally chartered advisory group to the U.S. Secretary of Energy, providing advice and recommendations on general policy matters relating to coal and the coal industry. In August 2016, the NCC completed a white paper for Energy Secretary Ernest Moniz that assessed opportunities to advance commercial markets for carbon dioxide (CO) from coal-based power generation. This article highlights key findings and recommendations from the report, “CO Building Blocks: Assessing CO Utilization Options”.
DRIVING THE NEED FOR CCUS
CCUS technologies provide the most impactful opportunity to capture, use, and store a significant volume of COfrom stationary point sources. These technologies can be used to reduce CO emissions from electric generation as well as from key industrial sectors, such as cement production, iron and steel making, oil refining, and chemicals manufacturing. Additionally, CCUS technologies significantly reduce the costs of decarbonization. Not including CCUS as a key mitigation technology is projected to increase the overall costs of meeting CO emissions goals by 70% to 138%. Finally, the commercial deployment of CCUS preserves the economic value of fossil fuel reserves (coal and natural gas) and associated infrastructure.
Commercial markets for COfrom fossil fuel-based power generation and CO -emitting industrial facilities have the potential to provide a business incentive for CCUS. The extent of that economic opportunity will depend on many factors, including but not limited to expediting the development of and reducing the cost associated with CO capture technologies. And while commercial markets may provide significant opportunities for CO utilization, the global scale of CO emissions suggests a continued need to pursue geologic storage options with significant CO storage potential and initiatives such as those being undertaken by U.S. Department of Energy (DOE) through its Regional Carbon Sequestration Partnerships Program and related programs.
Fossil fuels generally, and coal specifically, are dependent upon CCUS technologies to comply with U.S. GHG emissions reduction policies. A number of U.S. regulatory policies have been adopted to reduce GHG, with geologic storage options (specifically including CO-EOR) as preferred mitigation technologies. Included among existing and pending U.S. regulations that encourage compliance via the use of CCUS technologies are the Clean Air Act’s Prevention of Significant Deterioration (PSD) and Title V Operating Permit programs; the Environmental Protection Agency’s (EPA) Standards of Performance for GHG Emissions from New, Modified and Reconstructed Electric Utility Generating Units (111b); and the Clean Power Plan (CPP). These U.S. policies are reinforced by the 2015 Paris Agreement, which largely envisions the decarbonization of major energy systems through the use of CCUS and other technologies by the 2050 timeframe.
U.S. law currently favors geologic storage/utilization technologies; non-geologic COuses must demonstrate that they are as effective as geologic storage. Additionally, the emissions reduction targets and deadlines associated with U.S. and international climate goals point toward the use of CO utilization technologies that are either already commercialized or near commercialization.
CO-EOR represents the most immediate, most mature, and highest value opportunity to utilize the greatest volumes of anthropogenic CO to meet U.S. and global climate objectives (see Table 1).
GEOLOGIC COUTILIZATION MARKET POTENTIAL
A 2011 report from the Global CCS Institute estimated current global demand for COat about 80 million tons per year (MTPY) and suggested potential future demand could grow by an order of magnitude, reaching nearly 300 MTPY for each of a handful of technologies—most notably CO -EOR—and more modest growth for an additional group of technologies. The potential global demand for CO for EOR was confirmed in 2015 in an International Energy Agency (IEA) study indicating that, by 2050, conventional CO -EOR could lead to storage of 60,000 MTPY of CO and, through the application of advanced technologies, so-called EOR+ could increase to 240,000–360,000 MTPY of CO .
In the U.S., CO-EOR offers major potential for utilizing and storing CO in a diversity of geological settings.
Other geologic utilization markets—including tight oil/shale gas formations, enhanced coal bed methane (ECBM), and enhanced water recovery (EWR)—also hold current and future promise as incentives for CCUS deployment. Key knowledge gaps and technical barriers remain in the pursuit of commercial deployment of these technologies. Progress has been and is being made with these emerging technologies but additional research is required to advance to the next stages of technological maturity.
NON-GEOLOGIC COUTILIZATION MARKET POTENTIAL
Outside of CO-EOR and other geologic CO use markets, research is underway on two general paths for non-geologic CO utilization: breaking down the CO molecule by cleaving C=O bond(s) and incorporating the entire CO molecule into other chemical structures. The latter path holds relatively more promise as it requires less energy and tends to “fix” the CO in a manner akin to geologic storage. Utilizing CO in non-geologic applications faces hurdles, including yet-to-be resolved issues associated with thermodynamics and kinetics involved in the successful reduction of CO to carbon products and inadequate support for demonstration projects leading to commercialization. Still, these technologies are worthy of continuing evaluation, and many hold long-term potential in specific applications.
Non-geologic utilization opportunities that tend to “fix” COinclude (1) inorganic carbonates and bicarbonates; (2) plastics and polymers; (3) organic and specialty chemicals; and (4) agricultural fertilizers. Various technical and economic challenges face these commercially immature technologies, suggesting they are unlikely to incentivize CCUS deployment in the immediate future. They may, however, have an advantage over other non-geologic markets, such as fuels, which require cleaving of the CO bond through chemical and biological processes.
Transportation fuels do represent a significant market opportunity. They are, however, unlikely to incentivize CCUS in the immediate future for a variety of technical and economic reasons, including: (1) transportation fuels are ultimately combusted and thus release COto the atmosphere and (2) current U.S. policy favors geologic-based utilization pathways for Clean Air Act (CAA) compliance. Although the case could be made that some CO -derived transportation fuels have lower GHG emissions than fossil-based fuels on a GHG LCA basis, non-fossil-based transportation fuels still face significant market competition and displacement hurdles.
Market forces alone are unlikely to incentivize CCUS as COutilization faces numerous hurdles.
Thermodynamics & Kinetics of CO
The CO2 molecule is particularly stable and has a Gibbs energy of formation of -394.4 kJ/mol, which must be overcome.
Thus, breaking the C=O bond(s) and forming C-H or C-C bond(s), or producing elemental carbon, is possible. However, such molecules are at a much higher energy state, meaning that a tremendous amount of energy must be used. Converting CO2 to fuels or other high energy state molecules requires more energy input than could ever be derived from the end products.
CO2 can also be incorporated into various chemicals as a C1 building block. This is not thermodynamically challenged because the entirety of the CO2 molecule is used and thus the C=O bonds are not broken. For this application, the principal challenge is the scale of available reactants and market for products, both of which are dwarfed by global CO2 emissions.
PRIORITIZING COUTILIZATION INVESTMENTS
In its “COBuilding Blocks” report for Energy Secretary Moniz, the National Coal Council recommended that research investments in CO utilization technologies should be prioritized first according to the ability of the CO utilization technology to:
The Council further noted that monetary, regulatory, and policy investments in the following COutilization and storage technologies, in descending order, are most likely to incentivize the deployment of CCUS technologies:
Achieving stabilization of GHG concentrations in the atmosphere requires the deployment of CCUS technologies worldwide. Consensus grows among industry, the environmental community, and international governments that future COemission reduction goals cannot be met by renewables alone and that advancing CCUS is not just about coal.
COutilization technologies can serve as building blocks in advancing a foundation on which to achieve global climate goals. A broadly deployed mix of CO utilization technologies, including geologic and non-geologic, may help to advance CCUS incrementally and may, even if they do not offer full-scale carbon management solutions, provide sufficient incentive to keep CCUS technologies moving forward. CO -EOR offers the most immediate, most commercially mature, and highest value opportunity to utilize the greatest volumes of anthropogenic CO . Monetary, regulatory, and policy investments that prioritize geologic CO use technologies first while continuing to support non-geologic applications on a longer-term basis provide the greatest promise of achieving global climate goals.