The problem with these assumptions is that you are asking for yet-to-be-invented solutions to mining, transportation and processing problems. As a friend of mind is fond of saying, at some point we have to recognize that we took a problem from boiling a pot of water to trying to boil the ocean.
None of these proposals qualify as solutions, because they are never aligned with reality. Or, another way to put it: Reality is always far more complex than recognized by these experiments.
I do remember stories from undergrad engineering about the development of the first moon landing and the associated technologies. That and maybe the Manhattan Project.
In both these projects, budget was essentially unlimited, and ultimate success absolutely required planning around yet-to-be-invented technology. I see enough similarities to think something like this is possible. If, for instance, we thought seeding farmland soil reduced emissions by 99%, we'd probably do it. It's a leap of faith, but there is absolutely precedent.
> I do remember stories from undergrad engineering about the development of the first moon landing and the associated technologies.
Of course. However, in all of those cases you could go through the math in a brutally honest manner and determine that things were realistic within a certain margin of error given physics constraints.
The issue I have with every single proposal I have seen is that they are, to put it in a certain way, dishonest. It's the equivalent of "and then a miracle occurs" being reported as a real solution.
In this particular case, I would not have funded this research without first funding an initial (much lower cost) study to prove that the project meets basic physics. If, and only if, the researchers can prove the solution is actually realizable without causing damage, etc. We move to the next phase.
So, now you know it can be done without causing more damage and the numbers add-up.
Phase 2 would entail what I call a "sense of proportion" report. Again, much cheaper than funding the entire experiment.
What is that?
Before you launch into anything you need to understand what impact it might have if you succeeded at deploying it in the most optimal form imaginable. From there you grade it on a curve and try to estimate what reality might be. Is reality +/- standard distributions from the reported optimal value or worse?
The report would also have a "Comparables" section. Using language we use in the US when a home is appraised. Realtors find similar homes and look at how much they sold for to then compute the value of the home they are selling. This attempts to ensure that the home is sold for a reasonable price, not too low, not too high.
The "Comparables" report would compare the proposal to alternatives. In engineering it is always interesting to suggest new solutions to a problem. However, you always have to consider the alternatives or you risk wasting your time and money.
In this case the comparables might be what I mentioned in my original comment: One of the figures of merit they mention in the paper is CO2 reduction equivalent to removing 350K internal combustion (IC) cars from the roads. OK. Great. The question to ask, then, is: Can we achieve the same or better performance using other solutions, existing or under evaluation?
In the case of cars the obvious thing to look at is the replacement of IC cars with electrics. You have to evaluate that solution against the proposal before moving forward. Why? Because it is a real solution with real metrics we understand far better than a science experiment.
If all of the above and the comparison to known solutions shows the project might have merit within an acceptable margin of erro, and only if that is the case, then it gets funded and the required research begins.
Until all of the above passes basic math and physics, the entire thing is a big hand-wavy "and then a miracle occurs" fantasy. I am sorry to say that most of what has been proposed in this domain is nothing more than that, fantasies. Expansive fantasies that nobody ever seems to want to rigorously evaluate, as if reality didn't matter at all.
I want real solutions. I don't want us to waste time and money on fantasies, which is what we seemed to be doing. BTW, lots of money in the fantasy business these days. Maybe I should join them. It would sure be far more profitable than trying to point out the emperor has no clothes [0].
Just based on the downvotes and comments over the years on this topic, it is obvious to me, using HN as a sample of people who should be smart critical thinkers, that something is wrong. Perhaps people are so emotionally invested in the subject to forget that the very first job in science is to demand (and offer) proof of hypothesis based on the scientific method. This, among other things, requires full disclosure as well as the ability for anyone to verify and reproduce claims.
In this case, there should have been an entire section --pages-- on this report with an honest appraisal of mining, processing and delivery timelines, feasibility and consequences to the environment. Without that sort of thing it's like me showing a super efficient machine without disclosing that I am not accounting for additional energy being supplied from outside the system. Looks great. Dishonest as hell.
[0] For those who might not understand the relevance of the reference to the story by Hans Christian Andersen:
"Two swindlers arrive at the capital city of an emperor who spends lavishly on clothing at the expense of state matters. Posing as weavers, they offer to supply him with magnificent clothes that are invisible to those who are stupid or incompetent. The emperor hires them, and they set up looms and go to work. A succession of officials, and then the emperor himself, visit them to check their progress. Each sees that the looms are empty but pretends otherwise to avoid being thought a fool.
Finally, the weavers report that the emperor's suit is finished. They mime dressing him and he sets off in a procession before the whole city. The townsfolk uncomfortably go along with the pretense, not wanting to appear inept or stupid, until a child blurts out that the emperor is wearing nothing at all. The people then realize that everyone has been fooled. Although startled, the emperor continues the procession, walking more proudly than ever."
In this particular case, I would not have funded this research without first funding an initial (much lower cost) study to prove that the project meets basic physics. If, and only if, the researchers can prove the solution is actually realizable without causing damage, etc. We move to the next phase.
The basic physics is a known quantity and doesn't need to be repeated for every new study in the field. Here's a publication that contains the core insight of accelerated silicate weathering:
See section 7.2.2, "Chemistry of mineral carbonation."
The carbonation of magnesium and calcium silicates is thermodynamically spontaneous but kinetically hindered. The kinetic hindrance is why an additional energy input is needed to draw down atmospheric CO2 in less than geological time: the mineral's accessible surface area must increase dramatically for fast silicate weathering. The thermodynamic spontaneity is why the additional energy input can be small compared to the original energy embodied in the fuels that generated the CO2.
You are thinking about dust-in-dirt passing physics. That is NOT the entire process. That's the very end of the process.
Maybe you are not familiar with this use of the phrase?
Elon Musk uses the “it must pass physics” phrase to basically mean that the ENTIRE THING has to obey the laws of nature, not just the last step.
Perhaps this example can clarify the concept:
Using electrolysis to extract hydrogen from water is, to use your phrase "a known quantity and doesn't need to be repeated for every new study in the field". In other words, that process is real and "passes physics".
If, on the other hand, we propose to use electrolysis to generate liquid hydrogen to use as fuel, the ENTIRE PROCESS has to pass physics.
It does not.
Why?
Well, it takes approximately 55 kWh of electrical energy to extract 1 kg of gaseous hydrogen from water.
Great.
However, 1 kg of gaseous hydrogen contains 40 kWh of energy.
In other words, you have to use MORE energy to extract the hydrogen than the energy it contains. This idea, at the most basic level, does not pass the physics test. It's a fantasy.
Once we add such things as the inefficiencies of generating the energy, energy transportation losses (wires, connections, transformers, etc.), the energy required to bring the water to the electrolysis plant and run it at scale, the energy required to liquify hydrogen (12 kWh per kilogram), the energy required to transport and manage liquid hydrogen, etc. Well. The entire story quickly becomes a ridiculous fantasy. You are going to expend more than 100 to 200 kWh per kg of gas to deliver 40 kWh of stored energy in liquid form.
That's what "does not pass physics" means. The entire process cannot stand up to scrutiny when all factors are considered.
So, all of this, and the steps I have not listed (for example, fuel delivery), have to pass physics as a complete proposal:
- Mine massive far-away lava fields
- Likely use explosives, strip mining and very large machinery
- Burn large amounts of diesel and other fuels
- Generate massive amounts of CO2 through this process
- Cause serious environmental damage
- Transport what you mined
- Burn large amounts of diesel and other fuels
- Generate massive amounts of CO2 through transportation
- Crush it into a fine dust
- Consuming very large amounts of energy
- Generate massive amounts of CO2 through this process
- Transport massive quantities again
- Burn large amounts of diesel and other fuels
- Generate massive amounts of CO2 again
- Likely need for massive amounts of chemicals as part of all of the above
- Use a high carbon footprint process to distribute the dust
- Burn large amounts of diesel and other fuels
- Use a high carbon footprint process to bury the dust to the required depth
- Burn large amounts of diesel and other fuels
- Hope and pray for enough rain
- Hope and pray you don't destroy the fields for agricultural use
- Etc.
What I said is that phase 1 should be about proving that the entire thing passes physics. For that stage, it is OK assume that the proposed final element passes physics (whether we know it or not). What you are trying to quantify is everything else, which, in this case, is everything before a particle of volcanic dust finds itself 30 cm deep in dirt at a farm. That's what you have to prove before the physics of that dust particle in dirt is even remotely relevant in the context of the proposal.
Using electrolysis to extract hydrogen from water is, to use your phrase "a known quantity and doesn't need to be repeated for every new study in the field". In other words, that process is real and "passes physics".
If, on the other hand, we propose to use electrolysis to generate liquid hydrogen to use as fuel, the ENTIRE PROCESS has to pass physics.
It does not.
Why?
Well, it takes approximately 55 kWh of electrical energy to extract 1 kg of gaseous hydrogen from water.
Great.
However, 1 kg of gaseous hydrogen contains 40 kWh of energy.
In other words, you have to use MORE energy to extract the hydrogen than the energy it contains. This idea, at the most basic level, does not pass the physics test. It's a fantasy.
If the creation of hydrogen fuel via water electrolysis is an example of something that "doesn't pass physics" then the idiom "doesn't pass physics" obscures more than it clarifies. There is nothing physically implausible about water electrolysis. Despite the energy losses, water electrolysis to produce hydrogen fuel may be better than the alternatives; for example, you can launch a rocket to orbit with hydrogen fuel but you can't do that with electricity. If "doesn't pass physics" is supposed to be shorthand for economic implausibility relative to alternatives, just make the economic argument instead of referring to physics.
> There is nothing physically implausible about water electrolysis.
You are getting lost in the semantics and an example I grabbed as an illustration and ignoring the message, which is simple:
Anyone can propose anything. And that's fantastic. No problem. However, at some point, it has to make sense. And it has to make sense while looking at the entire process, not just a small element of it.
There are a lot of things in life that sound fantastic, until you run a full analysis and understand that they don't really make sense, particularly at scale. This has to be the first step.
Beyond that, after that step, the project has to be compared to other proposals that can deliver similar or better results. This, again, can usually be done before launching into these projects. It's about that list of dependencies I posted in my other comment.
Why?
Because we are wasting valuable time and money on fantasies, that's why.
Making a business comparison to try to further illustrate the point. In business you have to run through top level before jumping head-first into anything at scale. You also have to run competitive analysis and decide if your proposal is actually realizable and competitive.
In my work in aerospace I have to do this all the time. We are used to conducting what's usually called "Trades Analysis". This is a document where you present and analyze, to a sufficient level, all reasonable options to solve the problem you are trying to address. This is the starting point for a discussion that usually leads to choosing the solution or approach that makes the most sense within the stated objectives and constraints.
> If "doesn't pass physics" is supposed to be shorthand for economic implausibility relative to alternatives
No. That's not it. It really is about everything else first and foremost. Before you consider economics you have to consider science. Again, for the entire process, not a small portion of it. Of course, there are cases where the economics is so obviously ridiculous that scientific analysis quickly becomes irrelevant. A ridiculous example would be something like mining materials from the moon to make common concrete on earth. We don't need to look at science to know that would be economically and ecologically ridiculous.
> for example, you can launch a rocket to orbit with hydrogen fuel
If you change the problem, you change the required analysis methodologies. Still, you have to look at the process in its entirety and in the context of comparisons to other ideas. That's why nobody launches rockets into orbit using hydrogen. It doesn't make sense when looked at from a macro perspective.
My advice:
Always take a very large step back. Try to understand and quantify the entire picture. Things have to make sense at the macro level.
None of these proposals qualify as solutions, because they are never aligned with reality. Or, another way to put it: Reality is always far more complex than recognized by these experiments.