Direct Air Capture’s Role in the Energy Transition

Jesse McManus is one of ExxonMobil’s Carbon Capture Scale-up Engineers currently working in Direct Air Capture development. We spoke with him about the importance and challenges of direct air capture, its role in the energy transition, and what ExxonMobil is doing in this space.

What is Direct Air Capture (DAC), and why is it important?

DAC is an emerging technology that can be employed to mitigate global carbon emissions. Specifically, it is a technology that uses a contacting material to separate the CO₂ from ambient air so it can be recovered and permanently stored underground safely. This characteristic makes it both unique and essential in the CO₂ capture world because it doesn’t require pairing with a point source emission and it provides a scalable, definitive carbon-negative impact that reduces global CO₂ levels. In combination with worldwide CO₂ emissions reduction efforts and deployment of other CO₂ capture technologies, DAC will play a critical role in a net-zero world.

What role will DAC have in the energy transition?

The unique features of DAC as a carbon negative technology make it a crucial part of the energy transition. DAC is one of the few CO₂ mitigation options that provide high-quality, easily accounted CO₂ reduction credits. Furthermore, DAC is flexible on where it can be deployed and is able to capture CO₂ without a point source, so it is complementary rather than competitive to other CO₂ reduction technologies. Overall, this makes DAC ideal for offsetting emissions in the hardest-to-abate sectors like industrial and heavy duty transportation. The IEA projects a need for 85 Mt CO₂/year of DAC capture capacity within the decade, growing to nearly 1 Gt CO₂/year by 2050 for the net zero emissions scenario.

It is important to realize that DAC alone will not be an end-all-be-all solution for CO₂ management. Instead, it is a technology that provides unique solutions that supplement the other CO₂ capture and abatement technologies to put us on a path to net zero.

What are the challenges of this technology?

DAC has many complex technical and economic challenges, making it an exciting area to work in. Principally, DAC has the immense separations challenge of removing CO₂ from a highly dilute source – the atmosphere. At ~412 ppm, the CO₂ in ambient air is thousands of times less concentrated than point sources, which makes for two significant hurdles to overcome.

First, you need a separations platform that works well enough to separate such low concentrations of CO₂. Second, you need to design a system that can move extremely large volumes of air very efficiently. Moving such a large quantity of air is necessary to capture and sequester viable tonnage of CO₂, but doing so can be highly energy intensive if not designed carefully. If the process consumes too much energy when trying to capture the CO₂, that could dramatically reduce the net CO₂ negativity of the process and increase the cost of capture. Since the required energy for the process can’t decrease all the way to zero, it is critical to employ low-carbon energy sources in DAC operation, such as renewable electricity or conventional heat and power generation augmented with point source carbon capture, to maximize the net benefit of DAC. To be competitive in the CO₂ markets, DAC systems must be designed as efficiently as possible to reduce that $/ton cost.

Why should you care?

Working on technology solutions that help us get to net-zero emissions and help us manage the energy transition is an investment in all of our futures. Making a difference here is a responsibility we all share.

As chemical engineers, this is a technical challenge that fits right in our wheelhouse – we are the ones that really offer this technology a chance to succeed. DAC technologies pose difficult thermodynamic, transport, and kinetic hurdles that will require innovation, effort, and ingenuity. Making DAC a successful and viable option for the world’s carbon capture toolkit requires our help.

What is ExxonMobil doing in this space?

ExxonMobil has been engaging in research and development activities on DAC for years, and we have a unique, engineering-driven insight on how to make DAC a successful carbon capture technology. DAC can potentially become one of the leading technologies for atmospheric carbon reduction, and we can play a role in making DAC competitively scalable. Along those lines, we have been building pilot facilities to overcome some of the DAC technical challenges, leveraging our world-class active materials and engineering expertise to scale DAC to commercial viability.

How are you contributing to DAC, and why is this exciting to you?

As a Carbon Capture Scale-up Engineer at ExxonMobil, I have the privilege of helping drive DAC technology development and learning. My contributions can hopefully improve how quickly we bring DAC into the forefront of competitive carbon reduction technologies. This is a very fulfilling endeavor, where I get to be at the leading edge of a globally important technical innovation. The technical challenges are complex but rewarding to conquer, and their importance to the world makes me proud to be an engineer.

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Disclosure: This post is sponsored by ExxonMobil and reflects their views, opinions, and insights.