A Robot Dressed Like a Forest: Is DAC on the Verge of Becoming a Vital Climate Solution?
Loek Titulaer
Global Sustainability Principal @ SAP | Treat Carbon Like Money: the next Frontier in Embedded ESG Management
Some of the world’s foremost climate and energy experts claim that CCUS is a necessary and viable technology to help reach net-zero. For example, Dr. Fatih Birol, Executive Director at the International Energy Agency (IEA), argues that: “CCUS is a necessary bridge between the reality of today’s energy system and the increasingly urgent need to reduce emissions. Not only can it avoid locking in emissions from existing power and industrial facilities, it also provides a critical foundation for carbon removal or negative emissions”1.
On the other hand, CCUS has been criticized for a long time. Friends of the Earth, who won the People vs. Shell Case in 2021, said that: “fossil fuel CCS is a distraction from the growth of renewable energy, storage and energy efficiency that will be critical to rapidly reducing emissions over the next decade”2.
Understanding CCUS and Its Family of Solutions
CCUS is the abbreviation and collective noun for Carbon Capture Utilization and Storage?technologies which involves the capture of carbon dioxide (CO2), generally from large power generation plants or industrial facilities that use either fossil fuels or biomass as fuel. If not being used on-site, the captured CO2 is compressed and transported by pipeline, ship, rail or truck to be used in a range of applications, or injected into deep geological formations such as depleted oil and gas reservoirs.
Other forms of CCUS are Direct Air Capture (DAC) and Bioenergy with Carbon Capture and Storage (BECCS). The former relates to technology that captures CO2 directly from the air at any location - basically mimicking the photosynthesis process of trees. The latter is the implementation of CCUS to the bioenergy system. The main difference of BECCS in comparison with CCUS and DAC is that biomass production naturally takes carbon from the atmosphere using photosynthesis, such as trees and produces net negative emissions. This biomass is used in an industrial facility, producing heat and power (amongst others). So-called biogenic emissions from these industrial processes are then captured and sequestered permanently3.
In this article, my primary focus will be on DAC, as it garnered significant attention during the COVID-19 pandemic when oil and gas companies rushed to fulfill commitments for substantial CO2 emission reductions?. Additionally, a thorough individual assessment of CCUS technologies is crucial, given their intricate nature and the numerous factors that can impact their efficiency and effectiveness.
The Efficiency of DAC Technologies Today
Two primary DAC technologies have reached commercial stages today: liquid and solid systems. Liquid systems employ a hydroxide solution capable of rapid CO2 absorption from the air, forming water and carbonate, but it necessitates high temperatures (900°C) to release high-purity CO2 gas. In contrast, solid systems utilize sorbent materials requiring lower regeneration temperatures. Regardless of the material used, integrating DAC systems with low-carbon energy sources like solar, wind, and natural gas is crucial?. Currently, there are 18 operational DAC facilities across Canada, Europe, and the United States?.
DAC encounters numerous challenges, including high energy consumption and costs?, reliance on toxic solvents, releasing more CO2 than it captures, and potentially subsidizing oil drilling?. In particular, the last two challenges have captured my attention. Let's delve deeper into them, considering their interdependence with energy consumption.
Can DAC result in Negative Emissions?
Climeworks, a Swiss company specializing in DAC technologies, conducted a life-cycle assessment (LCA) in 2021, indicating that their commercial plants in Hinwil and Hellisheioi have the potential to achieve negative emissions. The study suggests that DAC, when combined with storage, could already contribute to negative emissions today. It's important to emphasize that this is a forward-looking perspective and not the current performance of the two commercial plants. Furthermore, the research highlights that capturing 1% of global annual CO2 emissions would necessitate the establishment of 3683 DAC plants, each with a capacity of 100,000 tons per year?. This underscores the need for rapid expansion and significant investments in this technology.
Additional comprehensive LCA studies underscore the critical role of choosing suitable locations for grid-coupled system configurations. Deploying DAC technologies in regions with carbon-intensive grid electricity sources can result in net greenhouse gas emissions rather than emissions removal, as of today1?. In simpler terms, currently, DAC plants worldwide do not extract more carbon emissions from the atmosphere than they release during the process.
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Does DAC Inadvertently Support Increased Oil Drilling?
DAC plants capture carbon emissions, which are sometimes stored underground but can also be utilized for enhanced oil recovery (EOR). EOR allows oil and gas companies to extract residual oil from fields that conventional methods cannot recover fully. This involves injecting CO2 deep into the earth. The advantage lies in the fact that the oil produced through this method has a significantly lower carbon footprint compared to conventional sources, provided that DAC replaces naturally-sourced CO211.
Hence, DAC could be perceived as a safety net that potentially hinders our current reduction efforts or sustains 'business-as-usual' approaches. Notably, seven prominent oil and gas companies are involved in DAC projects. Climate advocacy group Carbon180 has emphasized that DAC does not serve as a shield for offsetting ongoing fossil fuel usage. Nevertheless, Exxon Mobil has proposed an expansion of DAC deployments rather than a reduction in oil and gas production12. Darren West, Exxon Mobil's CEO, stated, “We are investing in point-source emissions reduction through carbon capture, which is more economically viable today and can assist society in addressing emissions from crucial sectors of the economy"13.
Is DAC on the Verge of Becoming a Vital Climate Solution?
Considering all the findings, it's challenging to definitively assert whether DAC will play a pivotal role in the necessary sustainability transformation at this juncture. Currently, DAC facilities do not appear to remove more CO2 than it emits, though this could change in the future. If it does, the cost of globally reducing even a small percentage of CO2 emissions through this method could be prohibitively high. Consequently, it's imperative for governments and policymakers to closely monitor this trend, as major oil and gas conglomerates might exploit unproven carbon capture technologies to maintain and expand oil production globally. In conclusion, DAC has the potential to become a significant component of the climate solution, but it's paramount to simultaneously reduce oil and gas production while investing in low-carbon alternatives to cut costs and promote wider adoption.
Disclaimer: This article relies on multiple sources and studies. Omissions of certain studies could yield alternative perspectives on the subject.
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