Carbon capture is an important means of addressing worldwide greenhouse gas levels, but where are we in terms of implementation?
Carbon capture will play a key role in decarbonization plans for businesses, countries, and the world. To understand the current state of affairs, I interviewed a few of my colleagues and examined the matter from their respective areas of expertise: technology, ownership, and permitting.
Specifically, I spoke with four specialists from POWER Engineers (POWER), an engineering and environmental consulting firm. Tom Rolfson, a department manager in POWER’s Environmental division, has many years of permitting experience within several industries, including power generation. Steven Babler, an air quality regulatory and permitting specialist, recently assessed regulatory implications of carbon capture projects. Dwight Cole, vice president of Project Management in POWER’s Generation division, specializes in decarbonization solutions. John Lagomarsino, a senior project manager also in POWER’s Generation division, provides technical advice in strategic selection of carbon capture technologies and project development.
Technology, regulations, economics, and workforce availability all factor into the carbon capture state of affairs. Multiple perspectives from these experts will paint a clearer picture and, ultimately, answer the question: what’s going on with carbon capture?
What is the current state of carbon capture technology and known issues?
Dwight Cole: Carbon capture is a known process in the petrochemical industry, so it’s not new. However, what is new is its use in capturing CO2 emissions from natural gas combustion exhaust, as well as in other industries (such as Portland cement). The technology currently deployed is amine scrubbing (Figure 1), which is used on dozens of power and industrial plants. It can be retrofit on existing sources or included as part of a new fossil fuel–fired plant. There are several suppliers of this technology—Mitsubishi, Shell, Linde/BASF, and Fluor are a few—each with their own features.
1. Simplified amine scrubber process flow representing currently available carbon capture technology. Courtesy: POWER Engineers
John Lagomarsino: Amine scrubbing requires significant cooling of the treated exhaust gas to absorb the CO2, and then reheating of the amine to release the captured CO2 and regenerate the amine solution. This cooling and reheating process requires large amounts of energy from the energy source, reducing overall efficiency. Additionally, the CO2 capture system’s pumps, blowers, and CO2 compressors consume a significant amount of electricity. Thus, there is a significant reduction in the overall efficiency of the energy source because so much of the energy produced is used for carbon capture, driving up operating costs.
Are there alternatives to amine scrubbing?
Lagomarsino: Yes. Alternative tech-nologies have moved from development into commercialization phases. One promising technology in particular is the Allam cycle (also known as the Allam-Fetvedt Cycle, named for its inventor, Rodney Allam), which utilizes the super-critical CO2 cycle and is oxy-fueled. The Allam cycle uses natural gas as the feedstock to create pure CO2 (for sale or sequestration); it also generates electricity at an efficiency on par with a traditional, combined cycle power plant (which does not provide carbon capture). Two more big advantages are lower water use, and low-to-zero emissions of other pollutants, such as nitrogen oxides (NOx). The Allam cycle system would replace a traditional fossil fuel–fired generating plant.
What is the status of technology for CO2 transporting and end-use?
Cole: The technology for compressing, transporting, and CO2 end-use is well developed. The pipelines are typically required to operate at very high pressures (2,000 psi to 3,000 psi), which requires special design for compressors and pipelines. The end-use of enhanced oil recovery (EOR) has been developed for some time now and is an established end-use of CO2.
Using CO2 to produce more oil can be counterproductive to decarbonization goals due to potential re-emission of the CO2. Dedicated geological sequestration, on the other hand, goes deep underground and requires significantly more compression and drilling, if a site can be found and approved. This may be reflected in the Inflation Reduction Act of 2022 (IRA) tax credit of $85/ton for permanent underground storage compared to $60/ton for EOR use. Developers are increasing in this sequestration industry—such as Verde CO2, which takes captured CO2 from decarbonization projects.
What is the state of direct air CO2 removal and sequestration?
Lagomarsino: Although one would think the sky’s the limit for developing numerous direct air CO2 removal projects, basic science and economics are still barriers for making this plausible, even with the introduction of tax credits of $180/ton. The primary reason is that the concentration of CO2 in the air is only 400 parts per million, whereas, the exhaust of a fossil fuel–fired power plant is 300 times higher and, therefore, removal is more cost-effective.
Are there any other hurdles for building infrastructure? How will workforce scarcity impact these efforts?
Cole: Absolutely. My understanding is that carbon capture in the U.S. needs to grow 400% per year in order to meet climate accord goals that limit global warming to well below 2 degrees—preferably to 1.5 degrees—Celsius, compared to pre-industrial levels.
The deployment goal for carbon capture infrastructure is to be net-zero by 2050—just 27 years from now. Hopefully, we have the bench strength of engineers, scientists, and other professionals needed to design and build enough infrastructure to meet this goal.
Who is installing carbon capture and why?
Cole: From our vantage point, it has primarily been owners of existing fossil fuel–fired power generation facilities—such as gas-fired combustion turbines and coal-fired boiler steam generating. The main driver has been the potential sale of the CO2 and, more recently, tax credits for CO2 removal. At $85/ton of CO2 (or even $65/ton for EOR), combined with the sale of CO2, the economics of carbon capture is beginning to pan out. I think this will continue to increase—it has to if we have any chance at net-zero by 2050.
Steven Babler: We have also seen an influx of developers and venture capital firms, specifically for installing new gas-fired capacity with carbon capture incorporated. Developers are also expressing interest in using the Allam cycle as an alternative to the traditional combined cycle, with carbon capture added at the end to clean up the stack. This would be particularly suitable for places like Illinois, which passed the Climate and Equitable Jobs Act (CEJA) in 2021. This legislation requires phasing in zero-carbon electric production between 2030 and 2045. The Allam cycle is theoretically zero-CO2 emission, whereas, well-designed, traditional amine scrubbing can achieve 95% and possibly 99%—but that would not satisfy the new Illinois law after 2045.
What issues are owners seeing?
Cole: The big issue is risk, in terms of reliability. Theoretically, an owner will make money based on the IRA tax credit and obtaining a reasonable sale price of CO2. The IRA has essentially removed the economic barrier. Industry participants indicate that the $85/ton tax credit is a solid number on which to base the economics.
However, the risk is whether the carbon capture system will operate as designed and promised, in terms of CO2 reduction percentage and operating costs. Because the economics are based on a very high reduction assumption (in excess of 95%), anything less than that means a significant reduction in CO2 tons removed for tax credit and for sale. Furthermore, generating income from CO2 reduction and sale depends on generating units operating under dispatch from the independent system operator (ISO) based on power production cost. If the operating cost is too high, the generator will not run—and the CO2 reduction and sale doesn’t happen. There are a lot of moving parts an owner must consider when investing in carbon capture.
Tom Rolfson: Another risk to owners, developers, and investors is the uncertainty of future. Through the years, regulations come and go as political winds blow. However, there is great momentum behind decarbonization—and it seems unlikely that the demand for carbon reduction or its funding will dwindle away. The CEJA legislation in Illinois, mentioned earlier by Steven, indicates that states are serious about this.
Is permitting an issue with carbon capture and sequestration?
Rolfson: Two issues are worth mentioning here. First, although the currently proposed amine scrubber technology is already used and understood in the petrochemical industry, it will be new to the electric power industry. It’s basically adding a petrochemical plant to your power plant—which means adding chemicals such as solvents to the plant inventory, which then impacts various Emergency Planning and Community Right-to-Know Act (EPCRA) reporting requirements like the Toxic Release Inventory (TRI) reporting requirements. New chemicals and oils will also impact the site spill prevention plan and stormwater discharge permits.
Second, the installed carbon capture equipment is large—surprisingly large. It will likely impact atmospheric dispersion conditions from the existing and new exhaust stacks and, as a result, permitting authorities will likely require dispersion modeling to prove that the non-CO2 emissions—NOx, SOx, CO, and particulate—will be acceptable. This takes additional time for preconstruction permitting and adds uncertainty to projects.
Babler: Although motivated by significant CO2 reductions (and resulting tax incentives and revenue stream), there is a potential for triggering new permitting requirements. The biggest issue is adding numerous compliance requirements. As equipment is installed and transitioned, the source must continue complying with their existing permits. They will also need to modify permits to account for new emission points (air and water discharge) and/or changes to the emission rates of existing sources. When adding and modifying equipment, the concern is triggering new requirements as a “modification,” which means new dispersion modeling, control technology, and purchase of offsets. Changes of permit modifications must be carefully examined, so that strategic assumptions and operating restrictions can be developed that limit the triggering of new regulatory requirements.
What about transportation of the captured CO2 and sequestration? Wouldn’t that require permitting?
Rolfson: Typically, the captured CO2 is either compressed and transported to a market through a pipeline; injected into the ground for EOR; or is further compressed to a much higher pressure and injected into a permanent sequestration underground storage. In all three scenarios, we are only dealing with CO2 and not other regulated pollutants; therefore, air permitting is not an issue (unless gas turbines or reciprocating engines are installed for compression).
Where permitting can become an issue is the siting, routing, approvals, construction, and operation of the pipeline system and sequestration. As with any linear facility, this involves land acquisition, environmental studies, mitigation measures, and agency approvals. It can also trigger the National Environmental Policy Act (NEPA) process and a years-long Environmental Impact Statement. The recent rise of environmental justice as an additional consideration will also play a role—especially in the appropriate siting of infrastructure. This may also be the case with sequestration with underground injection.
What is the future of carbon capture? Will environmental and permitting issues obstruct the progress of this key strategy for national decarbonization?
Rolfson: The future is bright! The key to any infrastructure development is considering environmental impacts in the feasibility stage and then designing features that minimize impacts (instead of adding them) during the permitting phase.
We should also carefully consider environmental justice in the siting process. With proper site selection, the required infrastructure should be permittable and approvable—especially when considering the significant environmental benefit of CO2 reduction. We all know it needs to happen—so if we will all share the commitment to carbon capture, we will also share the invaluable benefits.