Where is the energy coming from to sequester the CO2? I hope it won't be from fossil fuels.
"Right now, there is an ongoing discussion between a huge variety of stakeholders -- CO2 removal startups/companies, academics, regulators, 3rd-party verification standard-setting bodies, etc. -- to figure out what kind of life cycle analyses (LCAs) are required at the planning stages, and what verification frameworks will be needed post-capture/sequestration stages, to ensure that CO2 removal from air is removing more CO2 than it emits. In many of these discussions, and in the studies/analyses which drive them, moving to cleaner sources of energy makes a lot more sense given the total CO2 removed vs. CO2 produced/embodied in the system.
It is a complicated question and it really depends on what temperatures your process requires, where in the world you decide to build your removal system, if cleaner energy is available there (& at what cost), how you need to compress/store/transport the CO2 so it can be injected or converted into something else, and so on. Cleaner energy like geothermal, solar, nuclear, hydro, etc. are not always co-located near the best injection sites and there are questions of whether DAC is the best usage for cleaner energy resources vs. for general grid deployment.
To make a very long story short, cleaner energy makes CO2 removal a lot more sensible to pursue at scale, so that is where we are aiming as we think about the long-term system design."