So far all attempts at carbon capture are so horribly inefficient that I don't quite understand how this should or rather can work at all. If someone found a way to beat thermodynamics that would be quite the feat. The amount of energy required is so huge that CCS would never even make even a dent into atmospheric CO2 just from leftover energy from renewables. That doesn't even include materials and land use.
Unless we find a way to produce and recycle solar panels and wind turbines without any CO2 release and there is nothing else left that needs renewable energy it is probably still better to use fossil fuels for the few use-cases that absolutely require it.
Leave the task of capturing CO2 from the super low concentration in ambient air to plants and keep burning dead plants for heat like we have done since before we evolved into what we now consider humans. Capture from the chimneys where CO2 concentration could be measured in parts per dozen instead of parts per million.
Oh, I haven’t even considered the problem of the low concentration in the air. The problem of the energy loss from conversion alone makes capturing a net loss, even if we assume 100% pure CO2 and theoretically perfect processes. Not putting it into the atmosphere in the first place is the only viable option. Otherwise you spend at least the same energy again just to undo the initial pollution. Practically it’s much worse.
Actually, if the problem is concentrating the carbon, the current artificial methods are much more efficient than plants. Just like the current artificial methods for collecting solar energy are much more efficient than plants.
The one thing people are missing is a low waste method for converting the concentrated CO2 and energy into something useful.
What does "efficient" mean in this context? Maybe plants don't produce anywhere near the same number of kgs of CO2 for each Joule of sunlight, but that doesn't really matter. Plants are self-replicating machines which produce carbon as a byproduct. What matters is capital investment, human effort, or hydrocarbon energy per kg of CO2 produced. I imagine that plants are far more efficient in that metric than any current artificial process.
"Efficient" here is amount of CO2 captured by area. Not energy input, and certainly not by capital invested, but possibly by labor too.
For energy conversion, both by area, energy input, labor, and quite possibly by capital invested too, but both are close on that last one, so there's no clear win.
Both carbon concentration and solar energy capture are improving really quickly, so that picture may change soon.
Solar energy has certainly gotten much, much cheaper compared to decades ago, but there's only so much cheaper left to go before it reaches market price of plain sheet glass.
Collection efficiency is occasionally climbing a percentage point or two, but that's not an open end like a gut feeling raised on Moore's law might suggest. Even the hypothetical 100% cell that will never exist would not be a single order of magnitude better than what we have.
> but there's only so much cheaper left to go before it reaches market price of plain sheet glass
Yeah, I wonder who will be the first to make them over nylon cloth. On retail, photovoltaics already passed glass in lots of places.
But it doesn't need a lot of change to make it unequivocally cheaper than plants. Just the little margin of what we can do with the current design suffices.
By turning the area used into a techno-desert with a disposal problem at EOL. Plants can do carbon concentration at the side while solving other problems as their "main job". Food, materials for single use packaging, direct energy fruit (plenty of carbon in the lower energy value parts), or even just decoration. Surface demand for photovoltaics is bad enough already even before you add the absurd energy consumption of direct air capture.
If we can optimize existing processes or are able to utilize otherwise wasted energy I‘m all for it. This process seems to be limited by the MOF catalyst and how much sun can reach it. Would also be interesting if impurities lead to problems. I‘m not familiar enough with this process to judge if it is viable or a net positive however.
Unless we find a way to produce and recycle solar panels and wind turbines without any CO2 release and there is nothing else left that needs renewable energy it is probably still better to use fossil fuels for the few use-cases that absolutely require it.