In “Current Trends in Decarbonization - Overview“, it was noted that decarbonization simplified includes removing CO2 in producing energy and removing excess CO2 already in place. The latter is needed as NOAA (the US government’s National Oceanic and Atmospheric Agency) notes that even if we stop producing CO2 right now, the amount that is in the atmosphere, would remain for 300 to 1000 years and the warming of our planet will continue. As a result, we need to put a portion of the decarbonization urgency behind the development and implementation of capturing carbon dioxide technologies sooner rather than later.

Carbon capture comes in a variety of flavors depending on the source and what is done with it after it has been captured. In addition, because carbon capture is often misunderstood, the terms used to define the variety creates confusion. Let’s see if we can clear up some of it up.

Capturing carbon dioxide as it is being produced introduces the acronyms of carbon capture and storage (CCS) and carbon capture, utilization, and storage (CCUS). Sometimes the word “sequestered” is used instead of “storage”. The difference between the two is term "utilization". In essence, we are talking about capturing CO2 during the early lifecycle associated with creating the energy from fossil fuels. An example is installing a device on the smoke stack of a coal furnace. Once captured, if it can put to use, we then have CCUS. For example, using the CO2 as an injectant into an oil field in efforts to extract more oil. This utilization of CO2 also includes the storage facet as the CO2 is stored underground. An example of CCS without the utilization is capturing CO2 from forests or a smoke stack and simply injecting the CO2 underground. 

Capturing carbon dioxide after it is in the atmosphere is known as carbon dioxide removal (CDR). The technology can be simplified by describing it as literally sucking in air, removing the CO2 and spitting out air without the CO2. Like CCS and CCUS, the question is what do you do with it once it has been captured. The examples provided with CCS and CCUS can apply to CDR.

In addition to existing utilization and storage options, imagine there was a market for the carbon (the C in CO2) for products we need now and in the future? For example, can the carbon from CO2 be used to help manufacture concrete, pharmaceuticals, and synthetic fuels where battery technology does not address? The answer to all is maybe. The issues associated finding out are similar to decarbonization - technology, economics, politics, finance, environment, and culture.

With the goal of decarbonization being the reduction of CO2 circulating in our carbon cycle, a look at the carbon cycle clearly shows carbon capture must be an integral part of the equation regardless of the issues it face.

Epilogue:

To get a foundational understanding behind carbon capture, I recommend two sources. One is to read a primer on CDR at www.CDRprimer.org. The second is to listen to the episode “A Primer On Carbon Dioxide Removal” from the podcast show “Energy Policy Now” (dated March 23 2021).