The article annoyingly failed to close the loop from the $1,000/ton figure at the top and do the math on the economic efficiency potential of this approach. How much electricity is required to sequester each ton of CO2 using this method, assuming you can amortize the construction costs over some long duration? I assume the intended installation is on the exhaust of a fossil fuel burning facility, but is it possible to install this next to a solar field and generate ethylene from excess mid-day production? Large scale carbon sequestration is one of the major unsolved problems of the 21st century and we have to expect many false starts before the really viable technologies emerge.
> There is no hand waving about economies of scale or subsidies here, though we are eligible for the full IRA 45V green hydrogen tax credit, worth $3/kg-H2.
They're saying that they don't need the green hydrogen tax credit. The tax credit makes their product profitable sooner, but as long as solar keeps following it's cost curve for a couple more years they'll be fine without it.
Subsidized in what way? I've heard many dubious things in the UK / EU called "fossil fuel subsidies" when it's mostly generic things like electricity having a lower VAT rate than the usual 20% (or whatever) on most consumer goods. This is the sort of thing that gets called a fossil fuel subsidy. I think a lot of these things are grasping at straws.
The top subsidy of fuels that emit carbon emissions is the externalities experienced by future generations. Not really measured in numbers, it will just be a change in quality of life.
If they are sequestering by reducing (in the sense of donating electrons to) carbon, then that will, by thermodynamic necessity, require more energy input than oxidizing that carbon originally provided. Converting to ethylene, as they mention in the article, is such a process.
There are plenty of papers which look at precisely the economic and carbon tradeoffs of these sorts of processes. It all just depends on where you are. When you have a clean grid and a cheap grid, these methods become pretty feasible.
Take a look at De Luna et al, Science 364 2019 [1]
The writer appears to be under the impression that CO2 is not a valuable commodity.
In fact, it is, so long as it's under enough pressure, and in the right place. In Montezuma County, Colorado, sits the McElmo dome, an ancient underground CO2 well. They pump it out, down a 500 mile pipeline, to Denver City, Texas, where it gooses oil wells into pumping more crude out. Other than making more oil and making it cheaper, not really much in terms of greenhouse gas contributions- the CO2 starts underground and ends up underground.
Kinder Morgan won't just let you back up your truck and buy some (it's already spoken for), and even if they would, they'd expect you to pay a pretty penny for what we widely consider to be waste gas.
I think MIT is doing some good work. Just wanted everyone to be mindful of the massive scale under which CO2 is already getting bought and sold.
It's not that CO2 isn't valuable on its own, but that other carbon-containing molecules are even more valuable (especially when factoring in transportation costs). This helps prove out the technoeconomics of carbon capture.
Plus, if we wind down oil extraction, we'll need new processes to produce all the precursors we use for plastics. A cheap pathway to ethylene from captured CO2 and water would be huge.
How close to zero? 1 MWh at 100% efficiency is enough to convert 180 kg of CO2 to ethylene (note this only produces 51 kg ethylene). Annual excess carbon emissions are 36.8 trillion kg of CO2. At a cost of $0.10 per MWh, which is about 3-4 orders of magnitude lower than it currently is, that's still $20 Billion per year. A cheaper pathway is still going to save an incredible amount of money even if solar power got ridiculously cheap.
The energy costs are only part of the equation, though. Especially if your plan is to use excess renewable energy, the cost of your plant is a much bigger concern, because you can't run it all the time.
But that point drives right into this one: compressed CO2 is valuable. So the value of your carbon capture process is already very substantial after you've extracted the CO2 from the atmosphere. I mean I have a cylinder of CO2 under my kitchen counter right now for this reason.
So the question is, is this so valuable that it outweighs just selling that CO2 once you've pulled it out of the atmosphere?
It the example you give, CO2 gas is not really a valuable commodity. Pressure is the valuable commodity in that example, and so it's kind of irrelevant when discussing carbon sequestration solutions.
That's not correct. If pressure was all that mattered, we'd just run compressors on nitrogen (or formation gas). CO2 has properties that make it especially favorable for flooding.
Has to be both. A random gas might interact with the oil being pumped. Why don't they just use compressed air? There must be a reason why CO2 is desirable for that application.
It's the opposite actually; CO2 interacts with petroleum in controllable ways via pressure, so engineers can change the properties of the oil and end up extracting more oil more quickly.
So CO2 is magical here or would a reservoir of highly pressurized atmosphere be just as valuable? I think you are missing where the value is in this situation.
No. The value of commercial co2 is its energy content -- what it takes to process it into useful form. There is no useful form of co2 for making fuel. The energy has already been extracted.
You're right (current state of the art), but also wrong (in the spirit of the question as I read it).
If energy prices go down, e.g., from continuing decline of solar, then it may be very cost effective to store energy as hydrocarbons which are synthesized from cheap energy + CO2. E.g., make natural gas from the air and sell it cheaper than it could be extracted and transported.
In this scenario, rather than paying exorbitant fees for CO2, the cheap energy could be used to extract it from the atmosphere where it is abundant.
Before anyone bites my head off - consider the tyranny-of-the-rocket-equation problem of burning gas to transport gas from source (wells, refineries, etc) to consumers. Then consider that the sun shines most places, and CO2 is effectively uniformly distributed. So Synthesis wouldn't have to be cheaper at the source if it can beat the price at the consumer via avoiding huge distribution costs.
Electrofuels, also known as e-fuels, are a class of synthetic fuels which function as drop-in replacement fuels for internal combustion engines. They are manufactured using captured carbon dioxide or carbon monoxide, together with hydrogen obtained from water split.
It is my understanding that there is actually a shortage of concentrated co2 if we want to produce e-fuels as drop-in replacements in e.g. planes.
I wonder what happened to the Navy's attempts at synthesize aviation fuel in aircraft carriers. They have plenty of power (newer carriers have even more) and reducing or eliminating the need of support craft for fueling would be a massive bonus.
They've been looking at that for a while, I don't know what issues they encountered.
Exactly right. FTA: "The electrochemical process that converts CO2 into ethylene involves a water-based solution and a catalyst material, which come into contact along with an electric current"
That "electric current" is the challenge. It takes energy to convert CO2 into other chemicals. If that energy isn't carbon-neutral, you're just spinning your wheels.
> If that energy isn't carbon-neutral, you're just spinning your wheels.
True, but the "long term" angle here would be to supply that energy from, say, excess solar generation during midday after the overnight storage batteries are refilled.
It can be way worse than 100% if the reduced oil extraction costs (or greenwashed accounting from earning carbon credits for sequestration) results in more net oil being extracted, than there would have been without access to CO2.
Not to mention the energy costs of actually pulling carbon out of the air. Often, getting 1kg of CO2 out of the air ends up costing so much energy that you end up emitting more than 1kg of it.
If sequestration weren't a fairy tale that will keep us distracted for another few decades while we continue to ruin our environment, people would be doing it, not talk about doing it.
The application you mention does not rely on the gas being co2 at all. The gas is being used because it is in a high pressure reservoir. It could by any gas. The C02 itself is literally free because it is literally in the atmosphere all around us.
Pressure is only part of the equation. The pressure gets it to the field economically and does boos reservoir pressure, but co2 injection has more to do with miscibility with hydrocarbons at relatively low pressures. Miscibility yields viscosity reduction and swells the oil to improve displacement and mobility, particularly in heavier crude. Couple that with pressure and you can dramatically improve recovery factor.
Exactly. And getting back to the original poster's comment "the CO2 starts underground and ends up underground"... that assumes there are no leaks anywhere in the process.
That was exactly my point. What makes the co2 referred valuable is not that it is co2. We literally (not metaphorically, or hyperbolically, but literally) are surrounded by the stuff every day of our lives.
What makes it valuable is that the co2 is concentrated and under pressure. But pretty much any gas would fit the bill.
And let's not forget, the original article was about MIT scientists making extracting co2 from the atmosphere "more efficient". Which, as you point out, is a rather hopeless quest---in order to get the co2 back out of the atmosphere, you'd need more energy than you got from burning whatever put it there in the first place.
So making any meaningful dent in the atmospheric co2 by extraction/converting a mug's game. You'd need on the order of the entire amount of energy used by the human race during the entire industrial age.
Exactly my point. The original comment claimed that the co2 itself was valuable. It is not. What is valuable is that it is concentrated and under pressure.
Time scale is also something I want to know about. "Can I remove CO2 from the air and turn it into something valuable in a way that is cost effective?" is one question. Another question is, "Can I remove CO2 from the air and turn it into something valuable faster than a tree?"
I have not thought about this too carefully so I might be overlooking something. With that out of the way, a quick search indicates that we burn about 90 % of gas, oil, and coal for one purpose or another. Let's round this and pretend we burn it all. To undo this we will essentially need the same amount of energy again that we got out of it when we burned it, we would need to use all the energy coming from fossil fuels to undo burning them. Conservation of energy essentially.
Which makes it obvious that the entire idea is pretty pointless, burn fossil fuels to generate energy to then use it to unburn fossil fuels. To do it with renewable energy, we still need the same capacity as the fossil fuel capacity and when we have that - ignoring issues like fluctuations in renewable sources - it makes more sense to just use the renewable sources directly instead of using them to undo burning fossil fuels.
If you want to use the process to pull carbon out of the atmosphere, then you first have to replace all fossil fuels with renewable ones, then you can use additional renewable capacity to remove carbon. Add additional 10 % capacity to the world energy capacity to undo one year of carbon emissions every decade, at least to a first approximation.
To come back to the initial question, you essentially need an industry the same order of magnitude as the fossil fuel industry to have a meaningful impact. Not going to happen anytime soon.
Sure, if you capture carbon dioxide from the atmosphere to use it as a storage or transportation medium for renewable energy, that is perfectly fine. Trade some efficiency for overcoming some of the limitations of renewable sources like their variability or the difficulty to store electricity.
But that is not really carbon removal from the atmosphere, you take some out and later put it back. The article however frames the endeavor as removing carbon from the atmosphere, either the one we are currently burning or even the one we burnt in the past. Carbon removal by definition means we can not burn it later somewhere else, we have to permanently store it somewhere. There is no point in turning the carbon into some high quality product if we then just bury it somewhere, you want something cheap to make and easy to store.
As a non-fossile source for chemicals it makes sense but that is just a small fraction of our problem as we just burn most of the stuff.
Lots of solar on-site that doesn't need to transfer it's power elsewhere could be used; maybe the real winner would be 100% solar-powered solar panel factory :)
> To undo this we will essentially need the same amount of energy again that we got out of it when we burned it
Amine based carbon capture at the smokestack captures about 90% of CO2 with a 20% energy penalty. There's a new natural gas turbine design that captures 100% at no energy penalty (Allam cycle).
Both those technologies do not undo the burning process, they just capture the carbon dioxide. Like putting a gigantic balloon on top of the smoke stack to trap the flue gases. The real problem here is what do you do with all your captured carbon dioxide? You are producing it at the same rate as you are consuming fossil fuels, for each tanker, pipeline, or train delivering fossil fuels, you will need an equally sized tanker, pipeline, or train transporting the carbon dioxide to some storage facility. For each well or mine extracting fossil fuels you need a equally sized hole in the ground to dump the carbon dioxide into.
>>we would need to use all the energy coming from fossil fuels to undo burning them
This would true if we need to re-create the original molecule with it's stored energy (plus losses of course).
However, it seems this is a misapprehension of the task. Instead of trying to recover the entire hydrocarbon molecule, we're "just" trying to extract or recombine the CO2 reactant.
Without doing the chemistry or the math, it seems likely that a variety of methods of either preferentially attracting CO2, or combining it into simpler lower-energy-dense molecules to be collected, would require less energy as was in the original hydrocarbon, often substantially less.
Seems it should be an inequality, not an equality. Or am I missing something?
While you are right that capturing the carbon dioxide can be done with relatively little energy, that is not what the article is about. If you capture it, you end up with tons and tons of waste, essentially as much as the fuel you burned, what are you going to do with it? The article is about [...] converting CO2 into useful products [...] so that you do not end up with waste but useful products and the requires as much energy as you got from burning the stuff, at least to a first approximation, you would of course not try to recreate the exact same stuff you just burned.
If you capture the carbon dioxide, then for every supertanker full of oil you burn you need to permanently get rid of a supertanker full of liquid carbon dioxide. This is of course a project of insane scope given that we burn billions of tons every year. So in order to not have to deal with the waste, what if we just turn it into something useful that people will pay for? Because that costs a lot of energy, the energy we just extract. And now you want to put it back in? To get back what you just burned or at least something similar that you could almost certainly produce more efficiently directly from the oil?
OK, yes, building larger-molecule more-useful-stuff will take more energy, and I'll go with the first approximation that it's a similar quantity of energy re-input (some useful things less, some more). And yes, all that product will take substantial volume. Thx for clarifying.
That said, it still seems an extremely useful measure, even if we keep using only single-digit percentages for long-use plastics instead of hydrocarbon fuels.
Let's assume that for the next century or so a bunch of applications will continue to require the convenience and energy-density of liquid hydrocarbons. In order to avoid extracting more and further increasing CO2 levels, we'll have to input significant energy to reconstitute them from CO2. Obviously, inputting that energy from more fossil fuels defeats the purpose, but using renewables will work; and now they are even cheaper energy inputs.
The result would be a cycle of newly fabricated hydrocarbon fuels, which can be custom-optimised for each application. No new CO2 would enter the atmosphere and the existing levels would be reduced by the amount of hydrocarbon fuels (and plastics, etc.) fabricated and in existence throughout the entire chain of existence, fabrication, storage, distribution, transport, in-vehicle, right up to the moment it is burned. With cheaper renewable energy inputs and optimized custom fabrication, it would likely get cheaper than the existing drill/pump/transport/refine process. And, it's permanently sustainable, and as liquid hydrocarbon fuel use declines, custom production can be converted to storable materials.
The point that you're missing is that changes this equation a bit is that burning fossil fuels wastes most of the energy as heat another waste of energy is the amount of FFs we use to ship FFs to other places. So together that means we don't need the same amount of electric power to do the same amount of work. That being said, keeping fossil fuels in the ground will always be better than removing CO2 for the reasons you said. We also seem to be growing energy demands instead of shrinking or stabilizing them which also makes the transition harder.
As this is more of "can we make carbon sequestering commercially viable, or at least less lossy", I'm less worried about that and would be more concerned about the global market for ethylene being "316.8 Million Tonnes in the year 2023"*, compared to the tens of gigatons of CO2 emissions — though on the plus side, I'm optimistic about removing most of those emissions and this kind of thing is still fine for the last 10%.
As for "less lossy" even if it's not always a commercial winner alone: my guess would be there's always going to be an easier way to get CO2 than "from the air", unless you're on Venus or Mars: take tree (or coal), cut up, put chips in oven, set on fire. Much higher CO2 concentration than air, likely to make most things that need CO2 much easier.
A little stoichometry suggests that, ignoring oxygen, hydrogen, and energy input, the cited worldwide market for C2H4 would be satisfied by just about 1 gigaton of CO2. So if "we need to process gigatons of CO2 annually", that ethylene's gonna pile up.
What is smarter, spending years researching and arguing the best way to do this, or using the natural process all over, and adapting the best practice locally, to try to solve climate change?
Some places can plant trees, others grasslands. Or whatever, but it seems like there is a lot of money to create an industrial process that can be commercialized instead of just doing the work naturally...
If you use grasslands for grazing cattle you get meat, or also wool with sheep. Sequestering carbon into grassland soil (or into any soil, really) makes them better at absorbing and retaining rainwater, reducing the risks of catastrophic floods in the watershed area.
And the GP is quite wrong, because almost everything will be more efficient than trees or grass. Machines are just way more expensive, that's why nobody ever made them.
My guess is that it would be much more effective to capture and remove CO2 directly at the source, for example at a cement plant. While this could be done at a fossil fuel plant as well, it seems a lot less attractive: you give back most of the energy you just got from burning the fuel.
Have there been any recent developments in "lab-grown wood"? The last time I looked into it there had been some research on it (also at MIT), but there didn't seem to have been any updates for a few years.
They should sell it to people for their car tires with a specially colored valve cap like they do for nitrogen. It'd be stupid, but so is paying extra for a slightly higher nitrogen content and people do that.
Permeating the PTFE layer with copper electrodes in order to get both hydrophobicity and conductivity seems stupidly simple, but the best ideas often are. I also greatly admire how their model looks like a s'more lol
Perhaps someone with more knowledge can comment on why solutions like these can't be used to solve the energy storage problem. Is it just economics?
That is, renewables are now the cheapest form of energy by a significant margin, but they are unreliable with respect to timing, so a storage solution is necessary in order to provide electricity on cloudy days when the wind isn't blowing, at night, etc. Most of the research I've seen into solving the storage issue involves batteries or things like pumped hydro. If things like solar and wind were "overbuilt", could a solution like this be used to create hydrocarbons when there is excess electricity? Power prices already go negative in some places when it's particularly sunny/windy. If the excess energy at that time could be used to make gas that could then be utilized by gas plants, well then there is your net 0 storage solution.
I'm assuming solutions like this are uneconomic (and similarly with hydrogen plants, e.g. by using the excess renewable energy to generate green hydrogen by electrolysis for storage and later use), but I'd like to understand better why.
You kinda answered your own question already, I feel. The energy efficiency of cycling a battery (70-90% for grid scale) or pumped hydro (70-85%) is simply much, much higher than chemical storage. Here's a pretty recent one [1] showing 23% efficiency even at lab scale, and as described in the article scale is a big drain on efficiency.
We need massive amounts of medium-term seasonal (3-6 months) stable energy storage, and liquid synthetic hydrocarbons are not a bad solution. Low efficiency isn’t a dealbreaker when the inputs are free.
> Perhaps someone with more knowledge can comment on why solutions like these can't be used to solve the energy storage problem. Is it just economics?
Yes. If you round-trip energy through hydrocarbons, then you have to pay the "Carnot tax". Your heat engine will be at best around 50% efficient at transforming hydrocarbons into energy. This is then compounded with the inefficiency of reducing carbon dioxide to get maaaaybe 20% round-trip efficiency.
The tax is fine _as long as_ it doesn't have to be transported, assuming the energy would otherwise be wasted.
Which is why hydrogen solutions for stationary storage could be interesting, but the moment you start transporting them around they become less useful.
I'm not seeing that. Hydrogen requires a ton of very expensive infrastructure for storage. Its density is impractically low for storage in tanks, it can't be liquified under reasonable conditions, and reversible hydrogen-binding materials so far have all been duds.
If you happen to have an underground geological storage available, then it might be reasonable. Right now, there's a demonstrator project for that ongoing in Germany. I guess this qualifies as "local"?
So yeah, if you need storage for 3-12 hours of runtime, then batteries are fine. Sodium batteries are probably going to fit this niche once they become cheaper. Anything more than that is a big gaping hole in the renewable story with no good solutions.
There actually have been several solutions and some proofs of concept offered. However except for things like batteries, the purists object to all of them as green washing. Why, I don’t know.
Off the top of my head, I believe someone demonstrated you can add thermocouples to your water to generate electricity. The idea was that during excess electricity generation during the day by a homeowner’s solar panels, use that to heat up the existing water tank. At night, use the thermocouple to generate electricity from the hot water. Granted the efficiency is abysmal. But 5% of something is better than 0% which is what happens when the electricity is thrown away.
For hydrogen, you need an electrolyzer, a hydrogen fuel cell (or turbine), and storage. The electrolyzer is the main capital cost, and it is only running for a fraction of the day (either whenever there is curtailed solar/wind, up to 40% of the time you have your own captive plant). It needs to be sized for peak usage. The storage optimum depends on whether or not there is a nearby salt dome, but if not it is extremely expensive per kWh, and so days and days of storage are untenable (going directly to CH4 changes some of this). Existing fuel cells and H2 turbines have not yet walked down the learning curve in the same way that an NGCC plant has for CH4, but those are running 24/7 so the amortization is not as bad.
With a salt dome and captive PV plant, you end up with (optimistically) system capital cost that roughly doubles the PV capital cost (using US pricing). That means your amortized $/kWh rate is about 2x the PV rate. Since PV and NGCC are roughly the same $/kWh at the plant, it makes H2 extremely uncompetitive unless there is a carbon price or H2 subsidy. At $3/kg hydrogen, it's almost just barely within reach assuming everything works well. If the cost of electrolysis came down, or if H2 were easy to ship globally from high insolation regions, that would substantially help the problem.
We need vast amounts of energy storage is the problem and that won't be cheap no matter how you look at it. 20 years ago I saw an annalists that suggested the US needs the equivalent of lake Superior to get enough hydro storage - that is that much water, plus the ability to drain it all in just one day (to where!), and then pump it back up the next. Pumped hydro where we can use it should be used, but there isn't any place we can put it left (and we want to take some of what we have out because it is an ecological disaster). Batteries work but are expensive. This would probably work as well, but again be very expensive.
Remember you are competing with something we can pump/dig out of the ground for nothing anytime you propose storage. Renewables when the wind is blowing or the sun is shining are very cheap, but as soon as you need storage the costs go way up.
It's essentially just another form of energy storage. I don't think there's any deep reason why it is worse than the other methods currently available, it's just not cost competitive.
My understanding is that creating hydrocarbons is quite difficult and that you lose a lot of energy in the process. Otherwise, it would be a very compelling way of storing energy.
I guess for one, you have to get the carbon from somewhere, which means either taking sequestered carbon (which is counter productive) or capturing it from the air (expensive).
Interesting. PTFE tubes are used for 3D printers (although it's a small quantity and they aren't consumable), but I didn't know it was so much more harmful than other plastics.
Edit: just realized that PTFE is Teflon. Makes more sense now.
The novelty of the underlying paper notwithstanding, a quick scholar search for "gas diffusion electrodes ptfe copper" will show that this is hardly an unexplored space.
Indeed, this is at least a decade behind the state of the art for CO2 electroreduction and adding PTFE to gas diffusion electrodes is hardly a novel concept (see: H2 fuel cells which likely pre date it's inclusion in CO2 cells). It might be a good or even the best implementation of the concept, but if so it would be inches, not miles, better.
My wife actually has established a cheap, energy-efficient facility for converting CO2 into useful materials right in our yard.
She planted a garden.
I was thinking about that the other day, how our beautiful trees, flowers, and bushes draw a few minerals from the soil, but are really mainly knitted together from the components of water and CO2.
Yes, yes, I know, planting more trees won't do much about the greenhouse gas problem at scale, but the only thing that will are the three P's: powerdown, permaculture, population control. I do not expect industry to solve the problem industry created in a way that doesn't create more problems.
> Yes, yes, I know, planting more trees won't do much about the greenhouse gas problem at scale, but the only thing that will are the three P's: powerdown, permaculture, population control. I do not expect industry to solve the problem industry created in a way that doesn't create more problems.
But I am always wondering: Couldn't we have planted forests, from which we take the grown trees and put them back down under the earth, in some old mining facilities or dig some tunnels that lead deep down and put that stuff there? Or perhaps build lots of long term use furniture from the trees? Anything, except burning them or letting them rod? Then we would use nature's mechanism for capturing and prevent releasing, by putting it deep down, or making meaningful long term use of it.
And couldn't this be done on a bigger scale as well?
> Couldn't we have planted forests, from which we take the grown trees and put them back down under the earth, in some old mining facilities or dig some tunnels that lead deep down and put that stuff there?
This is basically how coal was created in the first place.
Assuming carbon in = carbon out, we'd have to plant trees for millions of years on virtually all arable land and bury them underground to undo our burning of coal, since that's how the coal (which is almost pure carbon) was originally created.
The problem is we're putting millions of tons of carbon into the air every year and it takes a while for a freshly planted tree to reach a ton of carbon stored. So you would need to plant millions of trees per year and take care of them for years before you can chop them down and bury them.
A garden actually isn't that great, it has limited CO2 storage capacity once it's in balance.
Productive land, specially timber, is a good way of capturing CO2, because it will end up stored in products.
We tend to naively think we should reforest land and leave it there, and it can be good for other reasons, but is a poor strategy for carbon capture. We need to _aggressively_ go back to using timber and vegetable fibers as construction material, instead of concrete and steel that have an enormous carbon footprint.
As someone New Orleans-adjacent, I totally support this and think timber use would be even better if we perfected techniques for strengthening wood through high pressure at construction scale.
I for one would love to see wooden skyscrapers with the aesthetic of the movie Her that are as strong as their concrete-and-steel equivalents.
> I do not expect industry to solve the problem industry created in a way that doesn't create more problems.
but it's not one "industry" that has to change their mind, this'd create a whole new secondary industry that is able to profit from negative externalities made by the former.
capitalism got us into this mess, but it's also the only thing powerful enough to get us out.
if we can get tech that allows us to make an economic case for reducing atmospheric CO2, it would be far more robust than relying on government regulation and/or unpopular moral appeals that ask people to sacrifice.
Just switch to EVs for transportation and it will be hard for the oil industry to keep going. Many wells will be closed despite being potentially productive just because there isn't enough demand to keep them maintained. Prices are likely to go up for plastics if there isn't much demand for oil as fuel just to keep all the oil stuff maintained - much of which is too big for their needs so the industry faces shutting down working refineries and building new smaller ones or operating the current ones at low capacity. And of course the plastics industry is also interested in going green, so if this isn't too much more expensive than oil based plastic they will switch anyway.
The question is how cheap can we do this process and how fast can we get transportation off of oil.
To remove the co2 we put into the atmosphere will always take way more energy than we got out of putting it into the atmosphere in the first place. That is just thermodynamics.
To remove all the co2 we put into the atmosphere would take more energy than we extracted from fossil fuels since the industrial revolution. And all that energy would, of course, have to be produced in an absolutely carbon-free manner.
So this is and will remain an entirely impractical method of combatting global warming. MIT engineers know this. The people who funded this research know this. Why are they doing this?
Obviously you cannot effectively pay off debt using the money that you borrowed: that just leaves you with a net loss of the interest/friction/inefficiency.
But if you can earn enough money to pay down the debt (which naturally also requires weaning off of the deficit spending in the first place) via other means such as renewable energy sources in great excess to the quantity of fossil fuel energy we have produced thus far, then figuring out how to pay down the debt as efficiently as possible as soon as possible absolutely makes sense.
The problem is how fast we are adding "debt". The earth is naturally slightly CO2 negative without human intervention. However currently there are thousands of years to make up for every year of CO2 we are adding. I say thousands, but I haven't been able to figure out a true number, so thousands is conservative, it could be in the hundreds of thousands.
We are kind of relying on the oceans to soak up excess atmospheric co2 at the risk of acidifying the oceans too much. It’s one of those things where it’s such a huge problem and for which we have no solution.
// If you can earn enough money to pay down the debt //
If we could divert enough energy to do that, we could have not put it into the air in the first place!!
We are talking about an absolutely ginormous amount of energy. It would take more energy than the human race has used since the industrial revolution to "pay down the debt" (to use your metaphor).
Portable, energy dense fuel is incredibly more valuable than grid electricity - especially back when most of it was burned, before modern battery technology.
It is not obvious to me that the net thermodynamics are important here. The only thing that matters is the real world cost vs benefits. Carbon free energy is extremely cheap now, and getting rapidly cheaper, yet still not very portable.
Positive interpretation: Because they hope to find a method of doing it, that does not require too much energy, so that that method can be done using renewables.
Negative interpretation: Because of look/appearances/prestige.
It inherently takes more energy to "unburn" co2 than you got from burning it in the first place. We burn co2-producing fuels just because of this fact--they give us tons of energy!
But it would take yet more tons of energy to unburn it. That is just thermodynamics. There is no magic science wand to wave here.
From the article : "The work was supported by Shell, through the MIT Energy Initiative."
Would it only exist to make people believe we can burn fossil fuels since a solution is around the corner ?
Okay, but why not work on making atmospheric methane more useful/practical? CO2 is less of a warming influence than methane, and there have been huge natural gas leaks (of methane) in the last 10-20 years. Even MIT admits that Methane is more important: https://climate.mit.edu/ask-mit/what-makes-methane-more-pote...
Carbon concentrations in Earth's atmosphere are a problem: a mess.
Weaning off of fossil fuel use and transitioning to sustainable energy production and storage is among the biggest steps to stop making more of a mess.
Carbon sequestration is cleaning up after the mess that has already been made.
I see no reason to hold off on performing one of these steps until after the other has been finished: both should be done at the same time.
I think the risk that carbon capture gives governments an excuse not to properly regulate emissions outweighs the possibility they actually succeed in removing carbon from the atmosphere.
On top of that, removing diffuse CO2 from the atmosphere requires far more energy than the bare minimum (i.e. the energy it released as fuel), because it is diffuse. The energy harnessed to do this (e.g. electricity from solar) would be put to better use doing actual work.
I think we would require an enormous surplus in power generation before carbon capture even registers on the scale of useful interventions.
Something that's not quite clear to me and is probably a stupid question if you know enough chemistry to be familiar with a gas diffusion electrode, but: can you run this thing on atmospheric air? Or will it only work if the gas in question is pure CO2?
Electrochemical cells (especially PEM electrolyzers) are notorious for containing materials far more expensive than copper (noble metals). But they pay for themselves much more quickly than you might think, if you can get offtakers to actually purchase and use the resulting products.
The biggest challenge facing these climate tech industries right now is the chicken-and-egg problem. You can't make anything cheaper than the centuries-old fossil-based competition unless you do it at scale; you can't scale it without offtakers; offtakers won't participate unless it is cheaper than the status quo.
There are compounding issues with expensive infrastructure upgrades (e.g. airplane or maritime engines that need to be upgraded to handle new fuels; pipelines or fuel trucks that need to be build to handle hydrogen, etc) that further push out the break even date. And then you have oil & gas companies inserting themselves into these efforts in order to greenwash their businesses, causing many would-be supporters to oppose entire clean technologies due to the perception that green tech startups are in bed with the fossil industry.
> The biggest challenge facing these climate tech industries right now is the chicken-and-egg problem. You can't make anything cheaper than the centuries-old fossil-based competition unless you do it at scale; you can't scale it without offtakers; offtakers won't participate unless it is cheaper than the status quo.
That's the exact sort of thing governments are supposed to solve.
It's also a marketing problem. As long as the product is a commodity, it's a margins game. As soon as you can differentiate it somehow there's room to be more expensive and still sell the product.
Just as an example that might be incredibly terrible for other reasons, I can imagine Ikea selling, say, furniture with plastics made from this particular ethylene source. They might explicitly mark it up somehow saying "this chair directly offsets a week's worth of car driving", or whatever, and done right, with the right choice architecture, people might be willing to pay considerably more for it than stock.
I am, as you can probably tell, no marketer. But part of the answer has to be to get it out of the commodity bucket.
Depending on how long the electrodes last the cost of the system will probably be dominated by the electricity, not the raw materials used in the construction. I have not done the chemistry, but my gut feeling is that breaking all of those O2s off of the CO2 and all of the O2s off of the H2Os is going to be the expensive part of this process.
What is needed is a Graphene Lightmill, turning driven by light alone, capturing CO^2 spinning out graphene as a monofiber, no in between steps, no conversions.
It's always going to take more energy to convert CO2 to anything useful than it is to burn energy and release it as pollution. That means to requester all the extra CO2 in the atmosphere will require more energy than it took to put it there in the first place. Good luck humanity.
Humans passively polluted the atmosphere. Perhaps they can passively clean it up as well. Electric cars that spend 10% of their energy on sequestration or something like that. Exchange your CarbonBricks for a discount on useless consumer trinkets.
Ultimately, it doesn't matter whether it's distributed or not, the real meat is that the energy used to sequester carbon needs to not come from carbon fuels. Once that can be scaled up, we can clean up at least some portion of this disaster.
https://terraformindustries.wordpress.com/2024/04/01/terrafo...
Their business model may have a slight problem.
Oil is subsidized to a much higher amount by the US government
Take a look at De Luna et al, Science 364 2019 [1]
[1] https://www.science.org/doi/10.1126/science.aav3506
In fact, it is, so long as it's under enough pressure, and in the right place. In Montezuma County, Colorado, sits the McElmo dome, an ancient underground CO2 well. They pump it out, down a 500 mile pipeline, to Denver City, Texas, where it gooses oil wells into pumping more crude out. Other than making more oil and making it cheaper, not really much in terms of greenhouse gas contributions- the CO2 starts underground and ends up underground.
Kinder Morgan won't just let you back up your truck and buy some (it's already spoken for), and even if they would, they'd expect you to pay a pretty penny for what we widely consider to be waste gas.
I think MIT is doing some good work. Just wanted everyone to be mindful of the massive scale under which CO2 is already getting bought and sold.
Plus, if we wind down oil extraction, we'll need new processes to produce all the precursors we use for plastics. A cheap pathway to ethylene from captured CO2 and water would be huge.
Is it considered cheap if the marginal cost of a PV MWh is close to zero ?
So the question is, is this so valuable that it outweighs just selling that CO2 once you've pulled it out of the atmosphere?
https://en.wikipedia.org/wiki/Carbon_dioxide_flooding
If energy prices go down, e.g., from continuing decline of solar, then it may be very cost effective to store energy as hydrocarbons which are synthesized from cheap energy + CO2. E.g., make natural gas from the air and sell it cheaper than it could be extracted and transported.
In this scenario, rather than paying exorbitant fees for CO2, the cheap energy could be used to extract it from the atmosphere where it is abundant.
Before anyone bites my head off - consider the tyranny-of-the-rocket-equation problem of burning gas to transport gas from source (wells, refineries, etc) to consumers. Then consider that the sun shines most places, and CO2 is effectively uniformly distributed. So Synthesis wouldn't have to be cheaper at the source if it can beat the price at the consumer via avoiding huge distribution costs.
Electrofuels, also known as e-fuels, are a class of synthetic fuels which function as drop-in replacement fuels for internal combustion engines. They are manufactured using captured carbon dioxide or carbon monoxide, together with hydrogen obtained from water split.
It is my understanding that there is actually a shortage of concentrated co2 if we want to produce e-fuels as drop-in replacements in e.g. planes.
They've been looking at that for a while, I don't know what issues they encountered.
My point was just about the scarcity of concentrated co2.
That "electric current" is the challenge. It takes energy to convert CO2 into other chemicals. If that energy isn't carbon-neutral, you're just spinning your wheels.
True, but the "long term" angle here would be to supply that energy from, say, excess solar generation during midday after the overnight storage batteries are refilled.
But yeah, it's quite underwhelming.
1 - Wild guess. But it's certainly less than 100%, and certainly not by a lot.
Not to mention the energy costs of actually pulling carbon out of the air. Often, getting 1kg of CO2 out of the air ends up costing so much energy that you end up emitting more than 1kg of it.
If sequestration weren't a fairy tale that will keep us distracted for another few decades while we continue to ruin our environment, people would be doing it, not talk about doing it.
Not exactly.
> The concentration of carbon dioxide (CO 2) in the atmosphere reach 427 ppm (0.04%) in 2024.
Any process that tries to unmix something is not going to be 'literally' free. And given the relative trace amounts we're talking here...
What makes it valuable is that the co2 is concentrated and under pressure. But pretty much any gas would fit the bill.
And let's not forget, the original article was about MIT scientists making extracting co2 from the atmosphere "more efficient". Which, as you point out, is a rather hopeless quest---in order to get the co2 back out of the atmosphere, you'd need more energy than you got from burning whatever put it there in the first place.
So making any meaningful dent in the atmospheric co2 by extraction/converting a mug's game. You'd need on the order of the entire amount of energy used by the human race during the entire industrial age.
Which makes it obvious that the entire idea is pretty pointless, burn fossil fuels to generate energy to then use it to unburn fossil fuels. To do it with renewable energy, we still need the same capacity as the fossil fuel capacity and when we have that - ignoring issues like fluctuations in renewable sources - it makes more sense to just use the renewable sources directly instead of using them to undo burning fossil fuels.
If you want to use the process to pull carbon out of the atmosphere, then you first have to replace all fossil fuels with renewable ones, then you can use additional renewable capacity to remove carbon. Add additional 10 % capacity to the world energy capacity to undo one year of carbon emissions every decade, at least to a first approximation.
To come back to the initial question, you essentially need an industry the same order of magnitude as the fossil fuel industry to have a meaningful impact. Not going to happen anytime soon.
Synthetic hydrocarbons let you use renewable energy shifted in time, space, modality or avoid capital costs.
- applications that can't use batteries, like long distance plane flights
- applications where it's cheaper to spend 6X as much for fuel than it is to buy a new vehicle
- for storage more than a few days
etx
But that is not really carbon removal from the atmosphere, you take some out and later put it back. The article however frames the endeavor as removing carbon from the atmosphere, either the one we are currently burning or even the one we burnt in the past. Carbon removal by definition means we can not burn it later somewhere else, we have to permanently store it somewhere. There is no point in turning the carbon into some high quality product if we then just bury it somewhere, you want something cheap to make and easy to store.
As a non-fossile source for chemicals it makes sense but that is just a small fraction of our problem as we just burn most of the stuff.
Amine based carbon capture at the smokestack captures about 90% of CO2 with a 20% energy penalty. There's a new natural gas turbine design that captures 100% at no energy penalty (Allam cycle).
This would true if we need to re-create the original molecule with it's stored energy (plus losses of course).
However, it seems this is a misapprehension of the task. Instead of trying to recover the entire hydrocarbon molecule, we're "just" trying to extract or recombine the CO2 reactant.
Without doing the chemistry or the math, it seems likely that a variety of methods of either preferentially attracting CO2, or combining it into simpler lower-energy-dense molecules to be collected, would require less energy as was in the original hydrocarbon, often substantially less.
Seems it should be an inequality, not an equality. Or am I missing something?
If you capture the carbon dioxide, then for every supertanker full of oil you burn you need to permanently get rid of a supertanker full of liquid carbon dioxide. This is of course a project of insane scope given that we burn billions of tons every year. So in order to not have to deal with the waste, what if we just turn it into something useful that people will pay for? Because that costs a lot of energy, the energy we just extract. And now you want to put it back in? To get back what you just burned or at least something similar that you could almost certainly produce more efficiently directly from the oil?
That said, it still seems an extremely useful measure, even if we keep using only single-digit percentages for long-use plastics instead of hydrocarbon fuels.
Let's assume that for the next century or so a bunch of applications will continue to require the convenience and energy-density of liquid hydrocarbons. In order to avoid extracting more and further increasing CO2 levels, we'll have to input significant energy to reconstitute them from CO2. Obviously, inputting that energy from more fossil fuels defeats the purpose, but using renewables will work; and now they are even cheaper energy inputs.
The result would be a cycle of newly fabricated hydrocarbon fuels, which can be custom-optimised for each application. No new CO2 would enter the atmosphere and the existing levels would be reduced by the amount of hydrocarbon fuels (and plastics, etc.) fabricated and in existence throughout the entire chain of existence, fabrication, storage, distribution, transport, in-vehicle, right up to the moment it is burned. With cheaper renewable energy inputs and optimized custom fabrication, it would likely get cheaper than the existing drill/pump/transport/refine process. And, it's permanently sustainable, and as liquid hydrocarbon fuel use declines, custom production can be converted to storable materials.
As for "less lossy" even if it's not always a commercial winner alone: my guess would be there's always going to be an easier way to get CO2 than "from the air", unless you're on Venus or Mars: take tree (or coal), cut up, put chips in oven, set on fire. Much higher CO2 concentration than air, likely to make most things that need CO2 much easier.
* https://finance.yahoo.com/news/global-ethylene-industry-repo...
In some climate zones, grasslands do it better than forests.
https://climatechange.ucdavis.edu/climate/news/grasslands-mo...
Some places can plant trees, others grasslands. Or whatever, but it seems like there is a lot of money to create an industrial process that can be commercialized instead of just doing the work naturally...
If you use grasslands for grazing cattle you get meat, or also wool with sheep. Sequestering carbon into grassland soil (or into any soil, really) makes them better at absorbing and retaining rainwater, reducing the risks of catastrophic floods in the watershed area.
You can make paper products including things like cardboard and packaging.
You can put livestock on it and produce meat.
Or if you just want to sequester carbon, you can harvest it and bury it deep in the ground.
And the GP is quite wrong, because almost everything will be more efficient than trees or grass. Machines are just way more expensive, that's why nobody ever made them.
That is, renewables are now the cheapest form of energy by a significant margin, but they are unreliable with respect to timing, so a storage solution is necessary in order to provide electricity on cloudy days when the wind isn't blowing, at night, etc. Most of the research I've seen into solving the storage issue involves batteries or things like pumped hydro. If things like solar and wind were "overbuilt", could a solution like this be used to create hydrocarbons when there is excess electricity? Power prices already go negative in some places when it's particularly sunny/windy. If the excess energy at that time could be used to make gas that could then be utilized by gas plants, well then there is your net 0 storage solution.
I'm assuming solutions like this are uneconomic (and similarly with hydrogen plants, e.g. by using the excess renewable energy to generate green hydrogen by electrolysis for storage and later use), but I'd like to understand better why.
You kinda answered your own question already, I feel. The energy efficiency of cycling a battery (70-90% for grid scale) or pumped hydro (70-85%) is simply much, much higher than chemical storage. Here's a pretty recent one [1] showing 23% efficiency even at lab scale, and as described in the article scale is a big drain on efficiency.
[1] https://www.nature.com/articles/s41467-022-29428-9
Yes. If you round-trip energy through hydrocarbons, then you have to pay the "Carnot tax". Your heat engine will be at best around 50% efficient at transforming hydrocarbons into energy. This is then compounded with the inefficiency of reducing carbon dioxide to get maaaaybe 20% round-trip efficiency.
And all of this with a huge capital cost.
Which is why hydrogen solutions for stationary storage could be interesting, but the moment you start transporting them around they become less useful.
If you happen to have an underground geological storage available, then it might be reasonable. Right now, there's a demonstrator project for that ongoing in Germany. I guess this qualifies as "local"?
So yeah, if you need storage for 3-12 hours of runtime, then batteries are fine. Sodium batteries are probably going to fit this niche once they become cheaper. Anything more than that is a big gaping hole in the renewable story with no good solutions.
Off the top of my head, I believe someone demonstrated you can add thermocouples to your water to generate electricity. The idea was that during excess electricity generation during the day by a homeowner’s solar panels, use that to heat up the existing water tank. At night, use the thermocouple to generate electricity from the hot water. Granted the efficiency is abysmal. But 5% of something is better than 0% which is what happens when the electricity is thrown away.
It's ~75% economics, 25% learning curve.
For hydrogen, you need an electrolyzer, a hydrogen fuel cell (or turbine), and storage. The electrolyzer is the main capital cost, and it is only running for a fraction of the day (either whenever there is curtailed solar/wind, up to 40% of the time you have your own captive plant). It needs to be sized for peak usage. The storage optimum depends on whether or not there is a nearby salt dome, but if not it is extremely expensive per kWh, and so days and days of storage are untenable (going directly to CH4 changes some of this). Existing fuel cells and H2 turbines have not yet walked down the learning curve in the same way that an NGCC plant has for CH4, but those are running 24/7 so the amortization is not as bad.
With a salt dome and captive PV plant, you end up with (optimistically) system capital cost that roughly doubles the PV capital cost (using US pricing). That means your amortized $/kWh rate is about 2x the PV rate. Since PV and NGCC are roughly the same $/kWh at the plant, it makes H2 extremely uncompetitive unless there is a carbon price or H2 subsidy. At $3/kg hydrogen, it's almost just barely within reach assuming everything works well. If the cost of electrolysis came down, or if H2 were easy to ship globally from high insolation regions, that would substantially help the problem.
Remember you are competing with something we can pump/dig out of the ground for nothing anytime you propose storage. Renewables when the wind is blowing or the sun is shining are very cheap, but as soon as you need storage the costs go way up.
If we could get controlled fusion though, we are going to see a massive surge of what you're suggesting.
My understanding is that creating hydrocarbons is quite difficult and that you lose a lot of energy in the process. Otherwise, it would be a very compelling way of storing energy.
I guess for one, you have to get the carbon from somewhere, which means either taking sequestered carbon (which is counter productive) or capturing it from the air (expensive).
Edit: just realized that PTFE is Teflon. Makes more sense now.
The novelty of the underlying paper notwithstanding, a quick scholar search for "gas diffusion electrodes ptfe copper" will show that this is hardly an unexplored space.
She planted a garden.
I was thinking about that the other day, how our beautiful trees, flowers, and bushes draw a few minerals from the soil, but are really mainly knitted together from the components of water and CO2.
Yes, yes, I know, planting more trees won't do much about the greenhouse gas problem at scale, but the only thing that will are the three P's: powerdown, permaculture, population control. I do not expect industry to solve the problem industry created in a way that doesn't create more problems.
But I am always wondering: Couldn't we have planted forests, from which we take the grown trees and put them back down under the earth, in some old mining facilities or dig some tunnels that lead deep down and put that stuff there? Or perhaps build lots of long term use furniture from the trees? Anything, except burning them or letting them rod? Then we would use nature's mechanism for capturing and prevent releasing, by putting it deep down, or making meaningful long term use of it.
And couldn't this be done on a bigger scale as well?
This is basically how coal was created in the first place.
https://en.wikipedia.org/wiki/Coal_forest
Assuming carbon in = carbon out, we'd have to plant trees for millions of years on virtually all arable land and bury them underground to undo our burning of coal, since that's how the coal (which is almost pure carbon) was originally created.
Housing is also a great carbon sink as the wood used in construction is protected from rotting.
Productive land, specially timber, is a good way of capturing CO2, because it will end up stored in products.
We tend to naively think we should reforest land and leave it there, and it can be good for other reasons, but is a poor strategy for carbon capture. We need to _aggressively_ go back to using timber and vegetable fibers as construction material, instead of concrete and steel that have an enormous carbon footprint.
I for one would love to see wooden skyscrapers with the aesthetic of the movie Her that are as strong as their concrete-and-steel equivalents.
https://www.archdaily.com/1006779/timber-skyscrapers-a-low-c...
but it's not one "industry" that has to change their mind, this'd create a whole new secondary industry that is able to profit from negative externalities made by the former.
capitalism got us into this mess, but it's also the only thing powerful enough to get us out.
if we can get tech that allows us to make an economic case for reducing atmospheric CO2, it would be far more robust than relying on government regulation and/or unpopular moral appeals that ask people to sacrifice.
The question is how cheap can we do this process and how fast can we get transportation off of oil.
To remove all the co2 we put into the atmosphere would take more energy than we extracted from fossil fuels since the industrial revolution. And all that energy would, of course, have to be produced in an absolutely carbon-free manner.
So this is and will remain an entirely impractical method of combatting global warming. MIT engineers know this. The people who funded this research know this. Why are they doing this?
Obviously you cannot effectively pay off debt using the money that you borrowed: that just leaves you with a net loss of the interest/friction/inefficiency.
But if you can earn enough money to pay down the debt (which naturally also requires weaning off of the deficit spending in the first place) via other means such as renewable energy sources in great excess to the quantity of fossil fuel energy we have produced thus far, then figuring out how to pay down the debt as efficiently as possible as soon as possible absolutely makes sense.
If we could divert enough energy to do that, we could have not put it into the air in the first place!!
We are talking about an absolutely ginormous amount of energy. It would take more energy than the human race has used since the industrial revolution to "pay down the debt" (to use your metaphor).
It is not obvious to me that the net thermodynamics are important here. The only thing that matters is the real world cost vs benefits. Carbon free energy is extremely cheap now, and getting rapidly cheaper, yet still not very portable.
You are obviously not a golfer.
Negative interpretation: Because of look/appearances/prestige.
It inherently takes more energy to "unburn" co2 than you got from burning it in the first place. We burn co2-producing fuels just because of this fact--they give us tons of energy!
But it would take yet more tons of energy to unburn it. That is just thermodynamics. There is no magic science wand to wave here.
Weaning off of fossil fuel use and transitioning to sustainable energy production and storage is among the biggest steps to stop making more of a mess.
Carbon sequestration is cleaning up after the mess that has already been made.
I see no reason to hold off on performing one of these steps until after the other has been finished: both should be done at the same time.
On top of that, removing diffuse CO2 from the atmosphere requires far more energy than the bare minimum (i.e. the energy it released as fuel), because it is diffuse. The energy harnessed to do this (e.g. electricity from solar) would be put to better use doing actual work.
I think we would require an enormous surplus in power generation before carbon capture even registers on the scale of useful interventions.
0: https://www.sciencedirect.com/science/article/pii/S258929911...
For the small amount of CCS we need, oceanic bio CCS is the way to go.
We're better off simply not emitting as much GHGs or digging up any more, and switching to renewables and distributed storage.
The biggest challenge facing these climate tech industries right now is the chicken-and-egg problem. You can't make anything cheaper than the centuries-old fossil-based competition unless you do it at scale; you can't scale it without offtakers; offtakers won't participate unless it is cheaper than the status quo.
There are compounding issues with expensive infrastructure upgrades (e.g. airplane or maritime engines that need to be upgraded to handle new fuels; pipelines or fuel trucks that need to be build to handle hydrogen, etc) that further push out the break even date. And then you have oil & gas companies inserting themselves into these efforts in order to greenwash their businesses, causing many would-be supporters to oppose entire clean technologies due to the perception that green tech startups are in bed with the fossil industry.
That's the exact sort of thing governments are supposed to solve.
Just as an example that might be incredibly terrible for other reasons, I can imagine Ikea selling, say, furniture with plastics made from this particular ethylene source. They might explicitly mark it up somehow saying "this chair directly offsets a week's worth of car driving", or whatever, and done right, with the right choice architecture, people might be willing to pay considerably more for it than stock.
I am, as you can probably tell, no marketer. But part of the answer has to be to get it out of the commodity bucket.
repeat
Ultimately, it doesn't matter whether it's distributed or not, the real meat is that the energy used to sequester carbon needs to not come from carbon fuels. Once that can be scaled up, we can clean up at least some portion of this disaster.