I’ve been fascinated by the thought of direct air capture and have watched a few videos on it, but inevitably, they always come back to pumping CO2 underground, and I can’t help think to myself:
- What a waste—there are so many products we use that have high carbon content; why not use that carbon for something productive rather than throwing it away?
- How long will that CO2 stay buried? Radon gas, for example, has a habit of escaping the soil into homes and buildings. Admittedly, I’m no chemist, but it seems like something the size of tiny molecules should be able to permeate certain soils—if that’s the case, then are we just setting ourselves up for future problems by doing this, metaphorically kicking the can down the road?
So, I’ve spent a fair bit of time thinking about #1. What high-carbon products do we use (or would we use, given a plentiful source of carbon) that we could produce from the CO2 we extract? I’m deliberately leaving fossil fuels out of the list since experts are saying that merely offsetting the CO2 we’re producing isn’t enough—even if we could reduce our net output to zero today, we’d still have too much CO2 in the air, and creating fossil fuels that we then burn and release more CO2 only undoes the work we’ve done in capturing it in the first place. Still, there are a number of things on the list:
- Carbon fiber
- Carbon nanotubes
Admittedly, I imagine not many people are using #2 pencils today (and those also contain something other than graphite in them to make them #2), but still. Everything I’ve heard is that carbon fiber is amazing but expensive to produce, and carbon nanotubes have amazing properties but are also too expensive to produce. Diamonds are hard to mine but can be produced synthetically and have amazing thermal conductivity and electrical insulation properties. Without wanting to devalue diamonds as gemstones, there are plenty of scientific and industrial applications where this would be useful if we had a supply of carbon to make them.
Again, I’m not a chemist, and it could be crazy expensive and energy-intensive to do what I’m suggesting, but in case it’s not crazy, I’m throwing it out there for somebody who knows the processes better than I do to take and run with. What if we capture CO2 like we’ve been doing but add another step to the process to strip the carbon off the CO2, resulting in solid carbon and oxygen gas? Then we’ve got this abundant source of carbon to make carbon fiber, carbon nanotubes, diamonds, graphite, etc. so that we don’t have to treat all that carbon like garbage, something to be buried out of sight?
This post made it look like there might be a chemical process that doesn’t involve heating the gas to 600 °C, and that makes me wonder: if we used renewable energy to power the reactions and set a few of these things up worldwide, could it make the price tag of carbon capture sting a little less, or would this add so much cost that it’s not worth the effort? I’m not an environmentalist or anything, but the idea of turning this waste product into something useful is very enticing to me, and I think that from the standpoint of getting commercial ventures to adopt it, there’s gonna have to be something in it for them besides government subsidies.