So you want to build a carbon capture company

Would you like to win one hundred million bucks from Elon Musk? Carbon capture (CC) is all the rage these days, with dozens of companies springing up to remove CO2 from the atmosphere and help stabilize the climate.

I am not an expert on carbon capture but I do get asked about it from time to time. As a public service, therefore, I am offering the following rubric as a means to organize our thoughts, refine our strategy, and champion quantitative rigor when it comes to developing and evaluating a wide variety of carbon capture systems. 

Is our carbon capture scheme any good at all?

Let’s examine our hypothetical CC machine from two angles: physics and finance.


Is our machine secretly a perpetual motion machine?

In a previous life I spent a few years designing maglev systems and quite often would see concepts from other designers whose performance was too good to exist in the real world. If the system has negative drag, it is a perpetual motion machine. 

If the system concentrates CO2 for less energy than releasing it back into the air, it is a perpetual motion machine. If our machine compresses a gas stream with no expenditure of energy or generation of waste heat, it violates the laws of thermodynamics. Perpetual motion machines obviously do not exist. Check the math! 

What do we know that no-one else does?

What’s a non-obvious controversial true fact? How does our system exploit this?

How much energy does our system actually use?

CC systems sometimes use thermal cycling of sorbent beds or electrochemical separation to increase the concentration of CO2 from ambient 420 ppm to close to 100% CO2. Does our system require lots of electricity or thermal energy to operate? How is it being provided? 

If the system is electrochemical, does it use more or less power per mole of captured CO2 than aluminium smelting? This is about 1500 kJ/mol. Is the power provided high current, low voltage? Do we have a homopolar generator handy? How much copper does the power system need? If we need X electrons per molecule of CO2 at a cell voltage of Y, this works out to be about X*Y*95 kJ/mol. How close is our current system to this limit?

Does our system net reduce CO2?

If our CO2 capturing system works by weathering Calcium Oxide (quicklime) that is produced by thermal calcination burning natural gas, it will emit more CO2 than it captures over a lifetime. Whoops!

More generally, how many years of operation are needed to offset CO2 emitted during production?

How are we thinking about theoretical limits?

The Gibbs entropy of CO2 dissolution in the atmosphere is about 19.4 kJ/mol. This is not much energy, which is why no-one generates power by leveraging the osmotic gradient of concentrated CO2 in the atmosphere. Does our system get anywhere near this? Does it have to? Can it? If we’re doing electrochemical separation, how are we capturing ohmic heating and viscosity as limits to our ultimate efficiency?

Is electrical efficiency even a major constraint to our system? Does it need to be efficient, and what’s the opportunity cost for increasing efficiency by 1%? If electricity gets 1% cheaper every year, is that equivalent to a free virtual 1% increase in efficiency?

Is our machine actually concentrating atmospheric CO2?

Our machine has flashing lights and a pipe that emits CO2 at a million parts per million. We’re good, right? Well not quite. Does the machine contain carbon? Are we sure we’re not accidentally combusting part of our machine? How sure? 

I think the gold standard here is that CO2 produced by concentrating atmospheric CO2 should have a radiocarbon age of zero (relatively radioactive) while CO2 derived from, say, accidental electrolysis of a mined carbonate salt will be very, very old with no radioactivity. Testing samples for Carbon-14 requires a mass spectrometer. There are numerous labs in the US which will perform tests for a few hundred dollars, though they generally have to convert samples to graphite first. 

Carbon dating isn’t foolproof, however, as organic sources of carbon, such as vegetable oils, wood, or charcoal, are also radiocarbon young. So if our machine uses crisco as a lubricant, we should double check the math, and also our life choices.

Can we defend our results?

Do we understand our test system? Have we quantified every aspect of its operation? If we’ve produced a video showing how it works, will it confuse potential investors? Are the key points obvious? Can someone watching the video easily imagine themselves building the same system and running the same test? Are test information data and results documented well enough to enable independent verification? Do we have a good understanding of what a well documented experiment looks and feels like, or do we need to go and read a biology paper or two?

There are plenty of very confused people out there in the area of CC, and we need to normalize a high level of rigor in our approach to documentation. We’re not planning on posting our trade secrets online (or are we?) but it’s unreasonable to expect investors to part with their money on a hope and a prayer.

Can we scale it?

Are there any fundamental physical limits on deployment? If we’re going to capture 10 GT of CO2 a year by planting trees, how much water will we need to irrigate them? More generally, how can photosynthesis keep up with fossil fuel extraction? What are the fundamental constraints on scaling? Capital availability? Indefinite returns on investment (ROIs)? Rare reagents? Flaky co-founders? Utility energy supply? Legal status of carbon taxes?

Is our CC machine ready to escape the lab?

The AC propulsion prototype used at Tesla in the early days was notoriously unreliable, using dozens of analog op amps to drive an AC induction motor. History is littered with projects whose costs were unsustainable because they were insufficiently mature to be put into production.

Do we have a desktop demo we can show people? Does it actually work? Is it quite clear which parts are hacks and which parts actually matter? Is it safe enough to put in a room with members of the public?

Is the tech ready to put into production? Can we hand the prototype to an average mechanical engineering graduate and say “make 10,000 of these” and have reasonable confidence that they’ll come off the line functional, reliable, and with decent yield? Have we worked out the bugs before the major capital investments, or is it still a science experiment?


What is our CO2 price?

Can we produce CO2 for $1000/tonne, $100/tonne, or $10/tonne? Where are we? Where do we want to be? Where do we need to be? How do we stack up against the competition? How credible is our path to improvement?

How expensive is our CC machine?

What is the CAPEX structure? How many tonnes of CO2 does the machine have to capture to pay only for the machine, less opex, financing costs, depreciation? How long does that take?

If our machine captures 1kg a day at a $100/T price point, it will earn $36.50 a year. If our machine costs $500 to build, it will take 15 years of operation just to cover construction costs. $500 for parts and labor falls somewhere between a nice cake and a very basic dishwasher in terms of overall scale and complexity. A half decent technician should be able to assemble half a dozen per day, which means our production rate must be at least 1500/year. Even then, total additional revenue will be about $50,000 which is barely enough to put one person through grad school.

If CAPEX is amortized over a decade or three of operation, how are we estimating our capital costs? Do we expect/rely on congress to underwrite big loans to ensure low interest rates, like with home mortgages? Are we going to become the underwriter for our customers’ loans to buy devices from us? How are we going to diversify risk in this sector given that many risks (technology, regulatory) are extremely correlated?

Or, can we make back the cost of construction in a few months or a couple of years, and thus access short term financing or even self-finance?

How quickly does our machine wear out? Do we have to depreciate it more quickly than we can pay it off? Are we going to self-cannibalize with version 2 and strand our early customers? Are they okay with that?

How expensive is our CC machine to run?

What are the operating expenses (OPEX)? Do we require labor for maintenance? What are the machine’s expendables, such as reagents, valves, fittings, pumps, electrodes, software?

How do operating expenses compare with the amortization schedule for CAPEX? Are we spending more on operations than CAPEX payments, and thus could justify adding complexity to the system to reduce ongoing expenses? Or is the machine so reliable, so set and forget, that NASA will use it for atmospheric regulation on a Moon base? 

Are we deploying in our backyard or in the middle of the desert somewhere? How do we access and support customers with hardware in remote or difficult to access places?

Energy, again?

Are energy costs important to the financial picture? Ten years ago, electricity costs made green hydrogen (produced by electrolysing water) prohibitively expensive compared to blue hydrogen (derived from natural gas via steam reforming). Today, solar PV electricity during peak hours is >10x cheaper. How does our business model and system optimization shift if electricity becomes more expensive, or cheaper, over the lifetime of our machine?

Is our process energy intensive? Is it comparable to refrigeration or electro-refining of magnesium? Could we be investigated for running an illicit growing operation or a data haven? 

How sensible is our supply chain?

Does our machine depend on any unusual materials? What can’t I get from McMaster-Carr, or Ali Baba? Or Silk Road? Is our supply chain fungible or do we depend on the business and good graces of a single supplier in outer Mongolia? Do we absorb CO2 with amines, zeolites, or MOFs? How expensive are these specialty materials? Are we related by blood or marriage with a lab that can actually make them? Can they scale production as quickly as we can scale business, and at what marginal cost? MOFs cost WHAT exactly?

Does our Bill of Materials contain anything (ANYTHING) considered more than usually toxic or requiring special handling? Any plutonium? Prohibited substances? FOOF? Piranha solution? Do we need certified technicians to do the work? Can we afford their fancy insurance? Are we going to get a visit from the DEA or DHS?

Does our process depend on the availability and good graces of one or more highly trained PhDs? Do we have a talent retention plan? How exotic is our process?

Do we need miracle materials to work?

Does our system only work with 99.999999% pure anything? Contamination: no problem, reduced efficiency, or spontaneous combustion? Will our catalyst get destroyed by exposure to common air pollutants, such as water vapor, oxygen, or the smell of pad thai?

Does our system expend its catalysts? Are they actually secretly consumables? Do we have a plan to supply, service, and replace stuff that we weren’t planning on breaking? How much cobalt do we actually need per tonne of CO2?

Do we need a miracle of scale?

Everyone knows that cars are only relatively cheap because of enormous complex, expensive tooling that enables a few hundred thousand to be made, exactly the same, every year. 

Does our CC machine have the same issue, where we can’t get CAPEX down to a reasonable level until we’ve designed and built a million square foot alien dreadnought fully automated lights out factory for it? Why can’t it be assembled like LEGO? Have we personally ever built a huge automated factory before? Is this expertise actually our value-add? Have we considered an “alien dreadnought factory as a service” start up instead?

More generally, is there a critical scale below which our system makes no sense? Can we justify the economies of scale or are we waving our hands because our system costs more to build than 20 years of operation at $1000/T can justify?

Do we have a revenue stream?

Or do we need, long term, to rely on coordinated legislative action by a few dozen national governments to emplace a reliable carbon tax/dividend so we actually have an infinitely deep, zero elasticity market to sell our CO2 to? 

Where does our concentrated CO2 go? Turning into fuel? Plastic? Carbon black? Graphite? Cement? Underground? Carbonated drinks? What is the annual capacity of these markets? How much of that can we capture? How much of that can we expand?

If we’re selling our CO2 only to PepsiCo, it goes back into the atmosphere very quickly. Do we have a plan to generate a more durable store of CO2?

Who is willing to buy our CO2, in what form, how much, and for what price? What does our business look like with this market saturated? For example, if we’re selling 1000 T/year for deep well injection at $100/T, our business has a revenue of $100k/year. Is that enough to support the team?

Where is the value generated in our business?

If we’re building a CC machine that must be amortized over 20 years, we’re selling very expensive widgets to debt-happy customers, and hopefully lots of them. What is expensive in that machine? Where are we adding value?

Let’s say we’re building CC machines that use a swing cell with zeolites, similar to the life support system on the International Space Station. A major cost of these systems is new zeolites. To reduce cost and improve quality control, we have decided to vertically integrate manufacturing of zeolites, and by doing so have improved the cost by 20%. As the zeolites were about 90% of the initial CAPEX of the machine, more than 95% of our company’s value-add is now in making zeolites. So are we really a zeolite factory in disguise?

More generally, if long term industrial scale CO2 capture does turn out to depend strongly on mass production of an otherwise exotic material, just as the computer industry has depended strongly on photolithographic etching of insanely pure silicon crystals, does verticalization of the industry make sense? Where are we starting on this value chain, and where do we intend to end up? Chemical supply as a service?

Concluding thoughts

What should we be thinking about?

Have I missed any obvious questions? Any un-obvious ones? Does this help us understand what needs to be done?

42 thoughts on “So you want to build a carbon capture company

  1. Anyone thinking about whether the machine needs cement to build at scale? Does the amount of CO2 generated by building and installing all of the machine parts inherently produce more CO2 than would be captured by the machine over its lifetime?

    Liked by 1 person

  2. The current best CO2 capturing machine is a plant – developed over millions of years to efficiently use solar energy to convert CO2 into organic compounds

    The best “machine” to remove CO2 from the atmosphere would be a machine to spread simple fertiliser over the deep oceans
    The deep oceans are “wet deserts” sun in the upper layers but no nutrients – nutrients near the bottom but no sun
    Adding nutrients to the top layers will grow phytoplankton, zooplankton and fish

    NOT to be used in shallow waters like the Gulf of Mexico where the problem is too much fertiliser

    Also in the running would be an OTEC plant,waters%20and%20deep%20ocean%20waters.&text=OTEC%20systems%20using%20seawater%20as,water%20to%20produce%20desalinated%20water.

    I love the idea of a power plant that has fish as a byproduct

    A long way behind these but still ahead of any mechanical device would be to grow “junk/weed crops” – harvest them and then landfill the harvest

    Liked by 1 person

    1. Many plastics can be made from plant cellulose.

      They are excellent replacements for many petrolium sourced plastics and have a long life in common use while remaining reasonably compostable to reduce ocean plastics.

      Additionally, plant fiber has been found to be excellent filler for concrete offsetting the carbon emissions of quicklime production.

      Liked by 1 person

      1. How are you economically getting sufficient water for your electrolyzing process in the arid regions where the cheapest solar, otherwise, lowers your total reforming costs? R.B.W., thanks!


      1. When in a hole – first STOP DIGGING
        The idea of things like Ocean Fertilisation is to help to fix the problem AFTER we have stopped burning fossil fuels

        Liked by 2 people

  3. I will add to my previous comment – while we should FIRST stop digging (burning fossil fuels)

    Ocean fertilisation has a potential that is orders of magnitude greater than any other technique !!

    The Earth is 70% ocean and about 70% of the ocean is “wet desert”

    That means that the oceans have a potential to INCREASE their carbon take up that is about a factor of five larger than planting on every piece of arable land on earth

    Or another way of looking at it is to consider it will have twice the amount of energy flowing into the process as covering the entire earth (land and sea) with solar panels would yield

    Liked by 1 person

  4. what if we could genetically create a zooplancton tha produce carbon/calcium carbonate shells thay will fall to the sea´s bottom whr dead, from where nothing will remove from there? like a super diatomaceus plaknton?

    Liked by 1 person

  5. In temperate ecosystems, soils store most of the carbon, so while plants capture it, a fast-nutrient-cycling, biotically active O layer is the most effective carbon storage going. Also, you get the added value proposition of increased rainfall infiltration, water filtration, and moisture normalization during dry spells, so whether or not you solve climate change, you’ve mitigated some of its effects locally.

    CCS machine evaluators should ask: why is your product better than no-till farming? Why is it superior to managed grazing with a healthy dung beetle population? Because these are mature technologies ready to scale across ~40% of North America’s surface area.

    The only system I’ve seen that looks like it might be competitive is Running Tide, who are growing kelp and sinking it to the sea floor.


      1. Soil carbon loss, however, accounts for around 40% of anthropogenic emissions since 1850 and is ongoing, so the net effect of making ag a carbon sink is pretty huge.

        Land surface area isn’t close to enough, but growing kelp in the open ocean increases surface area.


      2. Looks like if all ag land was made an extremely good sink, we’re probably only talking about a change in net emissions in the single digits.

        Some numbers on biological carbon capture:
        About 50% of total emissions are currently captured by biological systems. About 28% by terrestrial ecosystems and 22% by oceans.
        Agriculture monopolizes about 40% of land area and is a carbon source (1-3% of emissions).

        Click to access Keenan_AnnRevEnv_2018.pdf

        Liked by 1 person

  6. Another CCS issue to watch for: the value proposition to most current projects is enhanced oil extraction.

    Reducing the cost of liquid CO2 production will increase oil extraction opportunities. CCS machines should focus on other forms of CO2 concentration.


  7. The idea is to make cyanobacteria resistant to viruses so they would sink to the bottom of the ocean.

    Proposed here:

    “Cyanobacteria turn carbon dioxide, a global warming gas, into carbohydrates and other carbon-containing polymers, which sequester the carbon so that they’re no longer global warming gases. They turn it into their own bodies. They do this on such a big scale that about 15 percent of the carbon dioxide in the atmosphere is fixed every year by these cyanobacteria, which is roughly the amount that we’re off from the pre-industrial era. If all of the material that they fix didn’t turn back into carbon dioxide, we’d have solved the global warming problem in a year or two. The reality, however, is that almost as soon as they divide and make baby bacteria, phages break them open, spilling their guts, and they start turning into carbon dioxide. Then all the other things around them start chomping on the bits left over from the phages.”

    Liked by 1 person

      1. We could implement a kill switch into the modified cyanobacteria so when the job is done we kill all the modified cyanobacteria. Then the normal cyanobacteria will regain their position in the ecosystem.

        But I agree with you this is a hazardous plan.

        The scale of carbon capture is immense though, enough to offset all emissions, past and present.

        Liked by 1 person

    1. did you takeinto account that without CO2in atmosfere we will loose our breathing reflex and suffocate?


      1. Not even wrong. I’ve spent hundreds of hours breathing pure oxygen, as have thousands of others.

        None of these schemes come anywhere near reducing CO2 levels to pre-industrial, let alone zero.


    2. Actually, they seem to be actively working on the idea:

      “Half of the carbon sequestered on Earth through photosynthesis is stored in the oceans, and most of that is done by this one genus of cyanobacteria,” said Schubert. “So Synechococci already photosynthesize and sequester carbon very well.”

      “The question,” he said, “is whether we can create genetic tools that encourage them to pull even more carbon from the air.”


  8. I want to see a system that turns electricity, CO2, and water into sugar (all chemically, without making light and using it for photosynthesis). Then I want to see gajillions of square km of land taken out of food production and managed as quasi-wilderness for carbon sequestration.

    Liked by 1 person

  9. I think that carbon capture will be really useful once we’ve reached net zero emissions of CO2, to wipe out all the previous excess emissions.

    We could then do things to grow more biomass, reforest the deserts and restore natural habitats, mangroves, coral reefs, swamps, …

    With time the whole global ecosystem will adapt to the new conditions –warmer, with more CO2– and become more efficient in growing biomass. Eventually the level of CO2 will go down, maybe triggering a new ice age. The self stabilizing system before humans. Timescales in millennia here…


  10. As everybody nowadays, I have my own pet plan for CC, based on this:
    What we need to do is block the Strait of Bosporus, wait for the Black Sea surface layer to become fresh, and grow azolla there until the climate cools enough to make it impossible. The deep part of the Black Sea is a dead zone where carbon from sinking azolla can be safely stored.


      1. No, we can’t. Plankton doesn’t store carbon that efficiently, and azolla is a freshwater plant. Also, you need a closed basin with a dead zone at the bottom to make sure stored carbon doesn’t get carried out by currents. The Black Sea is the only place where you can do it. Azolla can fix nitrogen so it is uniquely good at quickly growing biomass.


      2. It is grown for biofuel. Corn crops, trees etc. eventually rot or get eaten and the carbon returns to the atmosphere. My Black Sea azolla sinks and takes the carbon out of circulation.


      3. Societal collapse or some other way of cutting those emissions. Nothing else can. But we still need a method for permanently removing carbon from circulation, and there are very few places where you can store it indefinitely without it oxidizing one way or another.


  11. Well, you have to multiply it by 10 to get rid of all the excessive carbon already in the atmosphere and the ocean before all boreal forests burn and cover glaciers with soot. That’s a lot of work producing, installing, servicing and replacing the solar batteries, plus you’ll be creating 200 cubic kilometers of HDPE per year – that’s a lot of mountains. And all those mountains need to be covered (to protect from UV) and kept in very dry places (to prevent evolution of bacteria or fungi capable of oxidizing HDPE).


  12. I have one more question about the carbon capture technology, if you can endure it, and that is to ask whether the adequate water production, if I’m correct, derives from the “sorbent” capabilities -as integral to the capture piece, at no net energy expense- or is does it instead derive from the electrolysis? My last question, I promise, what is your take on Goodnough’s “solid state“ battery claims? Thanks so much for a really heartening and fascinating forum and heroic endeavor, RBW


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