Unlocking the carbon-capture value chain

A: Carbon capture is a critical component for tackling climate change. If we want to reach a net-zero emissions case by 2050, removing carbon dioxide (CO₂) from the atmosphere must be on the agenda. Reducing emissions alone isn't going to get us there and that's where carbon capture comes in.

It's really the process of removing CO₂ in two general areas: from industrial sources before release to the atmosphere occurs, or through pulling CO₂ which has previously been released, out of the atmosphere (a.k.a. direct air capture). We then take those captured emissions and permanently sequestered them at depth, usually in a depleted oil and gas reservoir or in a saline aquifer far below the subsurface.

Q: The carbon capture value chain has many parts to it. Can you walk us through it?

A: The way I break it down is into five key parts. The first part is the source of those CO₂ emissions, whether high-purity emissions, low-purity emissions, or capturing super low-purity or maybe dispersing emissions from the atmosphere through direct capture. High-purity would be CO₂ that's released as part of, perhaps, hydrogen generation through the steam methane reforming from a process such as ethanol production. Low-purity would be something coming off a cement plant or from a coal-fired or natural gas-fired power plant. Direct air capture is pulling CO₂ out of the atmosphere.

The second part is the systems and technologies to remove or separate the CO₂. We have point-source capture methodologies such as absorption or adsorption, or membrane technologies that might be mounted right on the back end of an industrial process. In the third part, we usually have some type of treatment that happens, and that's primarily dehydration to get residual water out of that stream, and compression to get ready to move the captured CO₂. The fourth part is the transportation part of the value chain, which can be a pipeline or a ship or marine vessel in the case of cross-continent transport. There might also be truck or rail cars where we load and move the CO₂, which currently are infeasible if we want to scale this thing up.

The fifth part is what we do with it at the end point. It can be broken down into two different paths. The first is injection into the subsurface. That's going to be probably 95% of the case, where it's simply sequestered for good. About 5% of the case is utilization of CO₂, which can go into things such as specialty chemicals or even in the food and beverage industry where you might think of something like a carbonated beverage.

Q: Are there companies trying to tackle all this from end to end?

A: It's a very complex process. Certainly, there's a lot of different links in the chain from the source through to the eventual storage or utilization point. There are cases where individual entities look at owning the process from end to end, and this scenario becomes feasible when we have single-source, single sink arrangements. To make the economics work, you need the proper subsurface characteristics nearby to the emissions source, for one. On top of that, you've got to be able to secure a permit for such a well, and then be able to carry out all the well construction activities necessary to build that site

Because of this, what we see is more of a hub or a cluster concept rather than single entities trying to carry out all the steps in the process.

The idea is that on the source side, you might have multiple companies located in a small geographical area where we can get some efficiency by bringing together multiple point sources, and utilize shared infrastructure for transportation to a separate location offsite for sequestration. The storage site can be optimized for different things like subsurface geology or its location potentially away from metro areas.

Q: How do we keep track of the CO₂ molecules?

A: Just like any other commodity or waste stream, when there's a changing of hands or custody transfer, there must be some measurement that takes place to ensure that the parties agree to that trade. In the hub concept, one can understand why that becomes quite important. Furthermore, you can consider that while CO₂ is emitted as a gas, it's likely to be compressed to higher pressures and moved to a different state, potentially liquefied, before it's moved. As such, there's a lot of complexity to ensure the fact that all those measurement points match up across different phases. As we move toward globalized trade of CO₂, accuracy in terms of that fiscal impact becomes critically important. Ensuring that we see overall mass balance across that chain, and that we're truly sequestering and getting rid of the CO₂ that we've captured, relies on accurate measurement along the way.

Q: What are some of Emerson's technologies used in carbon capture?

A: Where we come in with Emerson's automation portfolio is that we truly span across that value chain from process optimization on the front end, to ensure carbon streams are captured as efficiently as possible, to optimizing the transport network, to building the systems that are used for custody transfer of carbon streams. We even help with modeling the subsurface for storage capacity and integrity.

On the measurement instrumentation side of the business where I sit, we're involved in everything from process measurement of things such as pressure and temperature to gas analysis, where we help understand CO₂ stream purity, contamination and water content, to metering the flow of those fluid streams.

We've been involved in the instrumentation of carbon streams for decades, and as a whole, that's something we'd consider ourselves highly experienced in with expertise and technology that can really be applied today.

Q: Any final thoughts?

A: We're encouraged by the speed at which some of these projects are hitting the ground running. It's exciting to see the openness and the collaboration that's taking place in a relatively new domain. It's uncharted territory for many who are starting their journey into carbon capture, and we're happy to partner with them on their energy transition goals.