Too much co2 in the atmosphere is assumed to be a bad thing.
Someone says they can sequester co2 from the atmosphere at a certain energy cost.
Is your point that this energy cost is unrealizable?
This is literally[1] burning $300,000 to save $100. No matter how well you optimise that $300K, it will never ever EVER be less than $100. It can't possibly be, that would break the laws of physics and you'd have essentially a perpetual motion (free energy) machine.
If you have 'x' units of carbon (coal), which you burn to make 'e(x)' units of energy and some CO2, turning the resulting CO2 back into 'x' units of carbon will always take more than 'e(x)' units of energy. There is no magical future science that can enable this. It's a fundamental law of thermodynamics!
If it were possible, then you could turn 'x' units of carbon back into 'x' units of carbon PLUS have some free energy left over by running the above in a loop. That's absurd. That's literally a perpetual motion machine. You could start with one ton of carbon and never need more to make infinite energy.
There is an endless series of "science" papers like this published every year, because it gets funding and attention from people that just don't understand that "there ain't no such thing as a free lunch". They're a total waste of time, and have the same logic as trying to power your ceiling lights by using solar cells as your wallpaper and then connecting the lights to the wallpaper. Isn't that brilliant!? The photons from the ceiling lights will produce electricity in the solar cells, which in turn will power your lights! Never pay electricity bills ever again!
NOTE: There are ways of capturing (not "un-burning"!) carbon dioxide and trapping it for less energy that was released by burning the carbon that went into it. That's fundamentally different, and potentially economically viable.
[1] Literally! Not figuratively! This process literally burns expensive gallium metal to produce cheap carbon and burnt gallium (gallium oxide).
If it requires that, then its even more pointless apart from the learnings of course, because such scenarios are super super rare in the real world of industry.
and in a marketing/politics point of view there is a LOT of bullshit going around about "Carbon Capture and Storage". This POC is likely to revamp that bullshit all over again.. its worth pointing out that this POC did not even slightly come close to the idea of "pulling carbon from the atmosphere".
The cost of doing it is so far down the list of reasons to not get overly excited about it.
The question is then, can we spin up sufficient capacity, and can we find a scalable, sufficiently efficient way of capturing said carbon, thus the research into this area.
Nobody is talking perpetual motion here.
If you just want to remove CO2 from the air, there are much better ways than “un-burning” it.
2: Solar is unreliable, requiring tiding over on nights/cloudy days/etc. In theory, this would allow for excess energy -> fuel, or other things, since coke is also useful for a number of other industrial processes.
3: Does this scale? I have no idea. It's not quite burning gallium though, since from what I'm seeing, gallium can then be regenerated to elemental gallium (at the cost of more energy). This is more an engineering, rather than a research question though.
4: This is just one of many projects (with some nice characteristics), if something else better turns up, then so be it.
This isn't a problem of scale, and the problem is that optimistic people just don't get this.
There is no way to make this work, ever. It's like the old joke: "Sure, we're selling every unit at a loss, but we'll make up for it with volume!"
You can't take a "business plan" that inherently loses money and try to scale it up to... what? Even greater losses?
(In this case, this is both a thermodynamic and a financial loss. You're burning both energy and cash!)
My life is bigger then lunch though. Lunch enables me to do other things that do make money - so I take a loss on lunch with a view towards the other stuff.
It’s impossible, of the perpetual machine variety.
This is precisely analogous to this gallium example! You can’t unburn something without losing more energy in the process than the burning produced. It’s always over 100% overhead.
ALWAYS!! The details and the path taken through the world of chemistry or electrochemistry are totally irrelevant and can never alter this.
Thanks to this technology with proper economic incentives we might use surplus electricity in peak renewables production hours to make carbon to burn later, or to bury underground.
Similarly, in this paper, electrochemical activity is converting CO2 and Ga into C and gallium oxide. The C and the Ga swap. The reaction is spontaneous. No need to add any energy for this reaction to occur; it proceeds because the products are more stable than the reactants.
Where is extra energy required in the process? Energy is required to melt the Ga to about 200C. Energy is also required to reverse the oxidation, i.e. to replenish the Ga. A supplement to the article explains that this was done by electrolysis: gallium oxide was converted into Ga and oxygen [0]. I guess, that they figure to use solar energy to generate the needed electricity.
I'm with you as regards the unfeasibility cost-wise. What they are obviously doing is exploring uses of low melting-point metals [1], hoping to strike it lucky with one of their projects. And, yes, these guys have obviously got their publicity department working overtime in order to generate more grants.
In a recent video, the co-lead scientist, Associate Professor Torben Daeneke [1], explains his various projects.
-- 13 min: The melting point temperatures of the metal/alloys they are working with.
-- 61 min: Their latest work , CO2 to coal.
And here's a video showing the bubbling of CO2 through Ga-In (gallium-indium) alloy to form carbon [2].
[0] https://www.rsc.org/suppdata/d1/ee/d1ee03283f/d1ee03283f1.pd...
[1] https://www.youtube.com/watch?v=fvsON7af2J0 Jan 2022
[2] https://www.linkedin.com/feed/update/urn%3Ali%3Aactivity%3A6...
All of these reactions just go “downhill”, and no amount of hand waving will make the uphill journey go away if you want to run any part of this in a loop — e.g.: to treat the gallium as a non consumable catalyst.
There is no infinite free supply of gallium, and there are no ski lifts in the electrochemical world.
Going uphill is the hard part. Any idiot can go downhill.