Oxxcu, converting CO₂ into fuels, chemicals and plastics | Hacker News Reader

Oxxcu, converting CO₂ into fuels, chemicals and plastics

maddyness.com

68 pointsPaulHoule84 comments

While these technologies definitely seem to have a future, it's important to remember that, in order to create fuel from CO2 it requires at least as much energy as burning fuel creates (at 100% efficiency), so in the long term this is more of a "way to compress excess energy from the grid for light-weight applications" rather than a replacement for all our current fuel consumption. It seems that they know that as well since they are targeting aviation.

Creating synthetic fuels also seems like the only practical option in the table for seasonal storage. If solar energy is free in summer, even pathetic round trip efficiency could be worthwhile to provide winter reserves.

If you're already making an energy-intensive material anyway, you can avoid the round-trip loss on seasonal storage by just going 'one way.'

https://www.moderndescartes.com/essays/factobattery/

The main downside to factobatteries is the same as for e-fuels: high capital cost due to low equipment utilization.

As that article says, there aren't many factories for what this is cost effective. (If energy costs are too low for it to be effective for aluminum smelting, you won't find many alternatives.)

What really means that it's a job for the government. Because overbuilding on solar is a social safety matter, and it will probably never be profitable. (As also is storage for long-tail events.)

  > As that article says, there aren't many factories for what this is cost effective.

... a problem that's even worse for e-fuels, because you have the same fundamental inefficiency plus round-trip losses.

That's my point.

  >What really means that it's a job for the government.

Subsidizing unnecessarily wasteful tech with taxpayer dollars isn't the answer, but of course you'll never hear that from the ones looking for a free handout...

The real answer? "It's the Market, stupid." A carbon tax (or even better, cap-and-dividend) is consistently rated as the most efficient solution by economists. One-sided subsidies (or even worse, privatization as you propose) unavoidably causes false corrupted price signals, which leads to both economic and energy inefficiency.

The government's proper role is to be the referee, not to pick winners and losers. The Invisible Hand Of The Market should decide which technology "wins," not some bureaucrat in Washington.

> of course you'll never hear that from the ones looking for a free handout

What government exactly? Because mine is a tropical country that won't need those things for decades.

But yay! Free market! Let's just hope your free market cares about you not freezing up on a 1 in 10 years weather.

Anyway, you do you.

I think we may be arguing past each other.

There's a difference between treating the market as an end and using one as a means. You (and yukkuri below) are criticizing the former, but I'm advocating the latter.

When society sets the values ("reduce this harmful pollution below X please"), a market can be a very efficient means of accomplishing that. NOx trading is one example. The problems come when the market itself starts getting held up as the primary underlying value in-and-of-itself.

Markets should be considered as powerful tools, not the main goal. Just my opinion. Anyway cheers.

No amount of taxing and mingling will make protection against long-tail events profitable. It's something that either the government does or it hires, the market will not provide. (But, well, it can order too, that works.)

For seasonal balancing, nothing is certain. Maybe you luck-out and there's a profitable way to consume the summer overproduction. But I'd advise against betting your life on it. Anyway, carbon taxing does absolutely nothing to change the profitability of this one.

The funny thing is that the US (I imagine this is your context, because most people thinking this way are there) is one of the democracies that most intervene on energy safety. It doesn't show on the final result, but the amount of reserves that government holds is so large that when it changes its mind on something it bankrupts people.

>No amount of taxing and mingling will make protection against long-tail events profitable. It's something that either the government does or it hires, the market will not provide.

[citation desperately needed]

Insurance seems to be quite an effective mechanism for handling rare events.

>Anyway, carbon taxing does absolutely nothing to change the profitability of this one.

Of course it does. When "Good Old Reliable" carbon-heavy baseload gets more expensive, that creates more incentive for storage (factobattery or otherwise).

Remember that the end goal is to achieve 100% renewable energy, not to build the most factobatteries. If you build more factobatteries than needed to efficiently achieve 100% renewable energy, you did it wrong.

The free market is horribly defective and how we got into all these messes. But have fun trying to be one of the exploiters until everything collapses because we refuse to regulate because it might earn one you less yacht

Am I being literacy handicapped or does this article read like the author have never seen a machine larger than a car? Turning on and off an industrial plant every days and nights? Surely that's like at least, during days and nights on the surface of the Moon?

> The main downside to factobatteries is the same as for e-fuels: high capital cost due to low equipment utilization.

shorter equipment life, and significantly reduced efficiency for things that require heat. A lot of processes are continuous, where the cost of stop/starting is much greater than absorbing the energy price differential. aluminium, smelting is a prime example. Yes you need kiloamps to smelt, but you also have to keep the alumina molten.

"Solar energy can now be stored for up to 18 years, say scientists" https://news.ycombinator.com/item?id=34027647 :

> /? MOST Molecular Solar Thermal Energy Storage

https://www.google.com/search?q=MOST%3A+Molecular+Solar+Ther... :

> ... Molecular solar thermal energy storage systems (MOST) offer emission-free energy storage where solar power is stored via valence isomerization in molecular photoswitches. These photoswitchable molecules can later release the stored energy as heat on-demand.

https://scholar.google.com/scholar?hl=en&as_sdt=0%2C44&q=MOS...

> The technology is based on a specially designed molecule of carbon, hydrogen and nitrogen that changes shape when it comes into contact with sunlight.

> It shape-shifts into an ‘energy-rich isomer’ - a molecule made up of the same atoms but arranged together in a different way. The isomer can then be stored in liquid form for later use when needed, such as at night or in the depths of winter.

> A catalyst releases the saved energy as heat while returning the molecule to its original shape, ready to be used again.

> Over the years, researchers have refined the system to the point that it is now possible to store the energy for an incredible 18 years

The Szilard-Chalmers MOST process.

And then at what efficiency? "How the gas turbine conquered the electric power industry" https://news.ycombinator.com/item?id=38307596#38314851

18 years of energy storage tops CAES Compressed Air Energy Storage, which is less lossy than batteries and ultracapacitors, and probably even molten salt, and maybe gravitational energy storage too?

Though, you could do CAES with captured CO2 and it would be less of an accelerant than standard compressed air. How many CO2 fire extinguishers can be filled and shipped off-site per day?

Can CO2 can be made into QA'd [graphene] air filters for [onsite] [flue] capture?

And for "carbon-free" air travel.

Seasonal storage for what kind of usage?

FYI, we have clean, and proven, energy sources in our toolbox that are not intermittent.

Plausibly, you could set up huge arrays of solar panels in sun-drenched regions bordering oceans, and just steadily fill up oil tankers with fuel as the process ran. The only material inputs are atmospheric CO2 and water, (plus catalysts, maintenance, etc.) and any electricity source - sunlight, wind, nuclear - could drive the process.

It's even worse, synthetic fuels (synthetic hydrocarbons, if using CO2) require a hydrogen input. So you need to factor in the energy needed to get that hydrogen.

On related good news, 100*100 sq km of solar panels in a desert is a mindbogglingly amount of carbon-free energy, accessible now on our current technology levels [1]

[1] https://blogs.ucl.ac.uk/energy/2015/05/21/fact-checking-elon...

Synthetic fuels are not an alternative to solar panels or wind turbines.

Synthetic fuels are the best method for long-term storage of the energy produced by solar panels or wind turbines and they will also always remain the best form of energy storage for the applications where the mass and volume are important, i.e. aircraft and spacecraft (as long as those do not use nuclear reactors).

The hydrogen for synthetic hydrocarbons will come from water, exactly like the hydrogen from all fossil fuels or from all living matter (even the hydrogen from volcanic gases or hydrothermal vents, which is used by bacteria, comes from water that has been reduced abiotically, mostly by the iron from magmatic rocks).

Unlike any other form of energy storage, the use of hydrocarbons for the long-term storage of the captured solar energy has already been demonstrated successfully for billions of years.

We can already have a better efficiency than the plants at the initial step of the capture of the solar energy. We must also attain an equal or better efficiency at carbon dioxide capture and at its conversion into hydrocarbons.

None of these carbon conversion companies ever talk about how they obtain their CO2 supplies, probably because it would reveal them as greenwashers. Although they attempt to imply that they are climate tech, they don't ever describe a solution for extracting carbon dioxide from the atmosphere, because they know it's economically infeasible. These carbon capture processes need a concentrated stream of CO2.

Let's compare carbon capture to the currently existing product that needs concentrated CO2, dry ice. Dry ice usually captures some concentrated stream of CO2 from an industrial process that creates it. The global market for dry ice is on the order of half a million tons per year. Meanwhile, the CO2 equivalent for global annual jet fuel consumption is on the order of 300 million tons. So it seems infeasible for carbon capture technology to replace even jet fuel, let alone all the other uses of fossil fuels needed for processes that require heat.

You can make dry ice directly from air, by cooling and compressing it, because after the condensation of water the other gases have much lower boiling temperatures than carbon dioxide.

Obviously, the efficiency of the cycle is lower when starting from air instead of from pure carbon dioxide, but the input energy is unlimited, as it comes from solar or wind energy.

This does not compete directly with batteries, which have very good cycle efficiency but poor mass, volume and maximum storage time. It competes only with other energy storage technologies that can also store energy for many years and/or which have comparable energy per mass and energy per volume ratios.

To judge whether the technology of this company can be competitive, we need some numbers that they do not provide. Nevertheless, it is also impossible to dismiss it a priori, because there are good chances for it to have a good enough efficiency.

What they say about having a better efficiency than the 2-step process through carbon monoxide is plausible, and even the indirect Fischer-Tropsch synthesis has been economically viable in the past, in the absence of enough fossil fuels, despite the fact that it is not competitive today, as long as the fossil fuels are still cheaper.

> Obviously, the efficiency of the cycle is lower when starting from air instead of from pure carbon dioxide, but the input energy is unlimited, as it comes from solar or wind energy.

What sort of energy inputs are required for a kg of CO2? If the process is so inefficient that e-fuels contain only a few percent of the energy inputs, then it's pretty unlikely to be a good use of electricity (even excess renewable energy).

That's the pivotal number. kWh per kg of CO2. It needs to be reasonable.

Ultimately only 0.04% of the air is CO2. You need to process a lot of air to extract large amounts of CO2.

If you look through your window, it is likely that you will see the proof of concept that the energetic efficiency of extracting the 0.04% of CO2 from air and the hydrogen from water, and of converting both of them into hydrocarbons can be high enough to allow you to breathe and to satisfy your hunger.

The artificial alternatives already have better efficiency for capturing the solar light and for extracting the hydrogen. It remains necessary to improve the efficiency of the CO2 capture and of the conversion to hydrocarbons.

Air has a bit over 400 parts per million CO2. Extracting CO2 from air in meaningful amounts involves pumping a lot of air.

The preferred source of CO2 for most carbon capture schemes is the exhaust fumes of those burning fossil fuels. Basically how this works is that you burn some dead dinosaur juice/lumps/gas, you capture (a fraction of) the CO2, use lots of energy to turn that into synthetic dinosaur juice/gas, and when you burn that, 100% of the CO2 ends up in the atmosphere. That's right, 100% CO2 comes from fossil deposits and at the end of the process 100% of it ends up in the air.

And 100% of the CO2 found in fossil deposits also originated from the atmosphere, many, many years ago (I.e when the fossils were not in the ground, that quantity of CO2 pre-existed in the air). Let us pause and think about that.

If we're being realistic, the road to a circular economy is going to be long.

We're still going to produce non-recyclable garbage in 50 years (you could potentially even reform that to hydrogen and carbon monoxide, lowering the energy requirements relative to synth fuel production from CO2), and the world will still be running gas turbine peaker plants for those wind-less winter days.

We might be running gas peaker plants in 50 years but there’s no way they will run on natural gas. The reduced scale, and gas being harder to find, will obliterate the economies of scale.

We’ll be running them on hydrogen produced from excess electricity on days with a lot of wind and sun.

There’s even some serious talks about delivering hydrogen over existing gas lines. Like all the off shore platforms in the northern sea can become hubs for off shore wind (super strong and stable wind all the way out there) that power electrolysis to send hydrogen to Germany.

I really hope it works out like this.

But right now, the technological challenges (electrolysis cells are expensive at GW scale, transporting and storing hydrogen is dangerous and expensive) are substantial.

I just don't see a scale where a hydrogen electrolysis facility that only runs on days with excess electricity production is more economically feasible than running a thermal hydrogen reformer of a natural gas pipeline and using the natural gas itself for the applications where you end up just burning it anyway.

Gigantic taxes on CO2 emission could fix this, but ever then hydrogen would need a couple of breakthroughs to make it more economical than carbon capture and storage.

There’s already a trial of CO2 capture at a trash burning facility in Oslo. I could see trash burning + CO2 capture becoming viable over time. Especially if that CO2 capture is paid for by carbon credits. (Yeah, reuse and recycle first, but eventually everything degrades and burning is in the end the best option , especially as modern processes lets us filter out heavy metals and toxic chemicals circulating in our materials)

I could also see e-fuels become competitive for larger remote islands that would otherwise import fuels. Could make them self sustaining. If they don’t go all-electric that is.

The jet fuels will be largely offset by battery electric flights IMO. Most miles flown are short range. It’s still a couple of decades out but I’m certain battery electric will be viable for short range flight eventually. The main challenge is designing the plane from the ground up to get the efficiency advantages of electric flight.

So I really don’t think we’ll end up needing all that much CO2. It’s basically fuel for a subset of planes and ships, and feedstock for some chemicals. That’s a minor part of the oil/gas usage and CO2 emissions today.

Notably they've quit building regional jets

https://en.wikipedia.org/wiki/Bombardier_CRJ

https://en.wikipedia.org/wiki/Embraer_ERJ_family

which will eventually lead to a crisis for small airports like

http://www.airnav.com/airport/KITH

It's already a big problem in economic development that many cities are stuck with airports with terrible service. Many organizations in Ithaca believe that the airport is a competitive disadvantage. Airlines are refusing to adopt next generation small aircraft like

https://en.wikipedia.org/wiki/Embraer_E-Jet_E2_family

even though the lower operating costs and better comfort (e.g. people who are riding an E2-Jet to get on a 737 would be shocked that the regional jet is a lot more comfortable than mainstream narrowbody airliners.)

Since regional jets are going extinct there will be a market for something else, maybe electric aircraft, because the competition from legacy aircraft isn't there. See also

https://www.raa.org/wp-content/uploads/2023/02/1Q23-Small-Co...

The most frustrating thing about the climate change discussion for me is that everybody's focused on the high effort, low impact changes. There are millions of hectares of rainforest being torn down every year... maybe we should turn our attention to that?

SAF will allow us to stop taking carbon out of the ground, but it does nothing to take carbon out of the air.

I think most of us would love to preserve the rainforest, but lack the tools to do it. We are therefore working on parts of the problem that are still very real, very consequential, and that we can control.

Solving climate change requires switching the infrastructure of humanity's heaviest industries, that produce at enormous scale, and are the product of centuries of optimization.

Doing this without a heavy green premium requires technology and innovation, allowing the replacement solution to be cost competitive. Otherwise, the lack of economic competitiveness will prevent new methods from replacing the old at any reasonable scale. We've already seen that policy alone (i.e., taxes) can't make it happen across all the sectors at the necessary speed, due to being vastly unpopular.

Unfortunately millions of hectares of rainforest is also mostly irrelevant compared to the amount of CO2 going into the atmosphere from burning fossil fuels.

You have to take into account not just the annual sequestration of carbon dioxide by rainforests, but also the carbon already stored within them that is released when they decay or burn. A lot of the land being deforested is used to make way for livestock which adds insult to injury. Moreover, the deforested land accelerates the greenhouse effect by absorbing more energy from the sun.

Why is the land being converted to meat production? Surely the problem is one of economics, development and poverty more than anything else? Give the people that live there better options and the deforestation will take care of itself.

The filthy rich (and constantly growing richer at the expense of everyone else) who are doing it have zero interest in giving the people that live there anything more than they absolutely are forced to give in order to be allowed to rape the planet for more profit. Giving the people that live there better options is the last thing they want to do, as then those people would have no incentive to give up their land and rights to make those rich people richer.

Right, but is anybody willing to pay for this? Not taking down the rain forest is opportunity cost. Who is going to pay for this?

Ironically, saving the rainforest is high-effort (requires Brazil's voters to elect leadership dedicated to it) and low-impact.

Replacing fossil fuels with renewables is the most attainable and impactful tactic at this point.

Is Brazil the only country with rainforests still standing?

Anyway, we should be working on artificially "hardened" cellulose. As well as ivory-like calcium-carbonate. I never heard about anybody working on those, but they clearly are in demand.

> Is Brazil the only country with rainforests still standing?

No, but 60% of the Amazon is in Brazil. The next-highest country is Peru at 12%, and the rest are much smaller.

Brazil is also the most egregious destroyer of rainforest in the world, and it's not even close[1].

"Saving the rainforest" is equivalent to "regime change in Brazil".

1. https://worldpopulationreview.com/country-rankings/deforesta...

You could imagine sanctions on Brazilian beef. Either a blanket ban or something targeted at particular producers. I doubt it would happen, but that's a different plan.

> Brazil is also the most egregious destroyer of rainforest in the world

Yet on that graph it has about the same color as every other country, way apart from the extremes.

Look at the numbers, not the colors.

The numbers that say "yeah, Brazil is the one with more forests standing"?

(But then, that link does answer my question upthread.)

I honestly can't tell if you're from Brazil, trolling, or not understanding the data.

Brazil has destroyed more than 3x the forest than the next-highest country, and the forest it's destroying is considered the most ecologically important. It doesn't matter how much is still standing. The rate at which it's being destroyed tells us which country's behavior needs to change.

This is similar to burning fossil fuels. We don't say, "Look at all the oil the US hasn't burned yet!" We say, "The US is the largest consumer of oil." We don't care about the damage they could do but haven't done yet. We care about the damage that's happening.

Now as it turns out, Brazil has already destroyed enough of the Amazon that it's now a carbon emitter rather than a carbon sink[1], so the task is not just to stop Brazil from destroying the Amazon, but actually to reforest it over time, which is even more challenging.

1. https://research.noaa.gov/2021/07/14/deforestation-warming-f...

> Brazil has destroyed more than 3x the forest than the next-highest country

And yet, the rate of destruction is well within the average for every country (what the graph measures).

I can only conclude that you don't perceive a difference between percentages and absolute values and there is no point trying to find common ground here.

Because the things that would actually work are political suicide because it would decrease the amount of "score" the plutocrats can accumulate in the "I'm richer than you".

Well, feeding the captured atmospheric carbon into stable material synthesis (carbon fiber and diamond, basically) is a more-or-less permanent removal mechanism. Over the long run, steady-state is most desirable when it comes to the global atmospheric composition of course.

So far all attempts at carbon capture are so horribly inefficient that I don't quite understand how this should or rather can work at all. If someone found a way to beat thermodynamics that would be quite the feat. The amount of energy required is so huge that CCS would never even make even a dent into atmospheric CO2 just from leftover energy from renewables. That doesn't even include materials and land use.

Unless we find a way to produce and recycle solar panels and wind turbines without any CO2 release and there is nothing else left that needs renewable energy it is probably still better to use fossil fuels for the few use-cases that absolutely require it.

Perhaps using this? https://phys.org/news/2022-06-holy-grail-catalysisturning-me...

If we can optimize existing processes or are able to utilize otherwise wasted energy I‘m all for it. This process seems to be limited by the MOF catalyst and how much sun can reach it. Would also be interesting if impurities lead to problems. I‘m not familiar enough with this process to judge if it is viable or a net positive however.

Leave the task of capturing CO2 from the super low concentration in ambient air to plants and keep burning dead plants for heat like we have done since before we evolved into what we now consider humans. Capture from the chimneys where CO2 concentration could be measured in parts per dozen instead of parts per million.

Oh, I haven’t even considered the problem of the low concentration in the air. The problem of the energy loss from conversion alone makes capturing a net loss, even if we assume 100% pure CO2 and theoretically perfect processes. Not putting it into the atmosphere in the first place is the only viable option. Otherwise you spend at least the same energy again just to undo the initial pollution. Practically it’s much worse.

Actually, if the problem is concentrating the carbon, the current artificial methods are much more efficient than plants. Just like the current artificial methods for collecting solar energy are much more efficient than plants.

The one thing people are missing is a low waste method for converting the concentrated CO2 and energy into something useful.

By turning the area used into a techno-desert with a disposal problem at EOL. Plants can do carbon concentration at the side while solving other problems as their "main job". Food, materials for single use packaging, direct energy fruit (plenty of carbon in the lower energy value parts), or even just decoration. Surface demand for photovoltaics is bad enough already even before you add the absurd energy consumption of direct air capture.

What does "efficient" mean in this context? Maybe plants don't produce anywhere near the same number of kgs of CO2 for each Joule of sunlight, but that doesn't really matter. Plants are self-replicating machines which produce carbon as a byproduct. What matters is capital investment, human effort, or hydrocarbon energy per kg of CO2 produced. I imagine that plants are far more efficient in that metric than any current artificial process.

"Efficient" here is amount of CO2 captured by area. Not energy input, and certainly not by capital invested, but possibly by labor too.

For energy conversion, both by area, energy input, labor, and quite possibly by capital invested too, but both are close on that last one, so there's no clear win.

Both carbon concentration and solar energy capture are improving really quickly, so that picture may change soon.

Solar energy has certainly gotten much, much cheaper compared to decades ago, but there's only so much cheaper left to go before it reaches market price of plain sheet glass.

Collection efficiency is occasionally climbing a percentage point or two, but that's not an open end like a gut feeling raised on Moore's law might suggest. Even the hypothetical 100% cell that will never exist would not be a single order of magnitude better than what we have.

> but there's only so much cheaper left to go before it reaches market price of plain sheet glass

Yeah, I wonder who will be the first to make them over nylon cloth. On retail, photovoltaics already passed glass in lots of places.

But it doesn't need a lot of change to make it unequivocally cheaper than plants. Just the little margin of what we can do with the current design suffices.

Back in the 90’s there was a company in Tulsa called Syntroleum that was using Exxon catalysts that were coming off patent to build mobile GTL facilities that could be placed in oil fields to convert Natural gas being flared to synthetic fuels via FT reactions. Despite a free feedstock and support from big oil they couldn’t make it work with proven technology. I doubt these guys will do better in a work with nonzero interest rates.

While the CEO isn't really clear in the article about the specific technology being used for the direct route, based on the other co-founders of the company and their publication record, it's probably found in this 2020 Nature paper (see Figure 5, 'Reaction Scheme for CO2 hydrogenation to jet fuel range hydrocarbons):

https://www.nature.com/articles/s41467-020-20214-z

In the long run, international air travel is the most secure market for artificial photosynthesis-sourced long-chain hydrocarbons (rockets seem to be going to methane, though you can make RP-1 this way too). I do wonder how big a facility (counting all the wind turbines / solar panels / nuclear plants for the energy source) would be needed to provide all the fuel needed for a large busy international airport. (Heathrow consumes ~16,000 tons of jet fuel per day, for example).

Twelve [0] is a notable player in this space -- they broke ground on a commercial-scale facility in Washington last year.[1]

[0] https://www.twelve.co/ [1] https://www.commerce.wa.gov/news/twelve-announces-plans-to-s...

These "turn polution into X" technologies are fraudulent on their face. Carbon is extremely easy and cheap to source. However the cheap plentiful sources are not tightly bound to oxygen and thus requiring a massive energy input to use. Then there is the need for hydrogen as well, which would mean splitting water, which is also energy intensive.

Theres no scenario I can think of where it actually makes sense to use 5000 units of energy to clean up the CO2 generated by the production of 100 units of energy, rather than just turning off the 100 and keeping the 5000 instead. The obvious case would have been offsetting cars, but hybrids and electrics make that absurd as well. This is a scam.

CO2 is fungible. If a plane produces CO2, we should still replace all the coal power plants before we worry about airplanes. Once all the coal and oil and natural gas uses are replaced by renewables there is no need to offset planes anymore as humanity is well below the CO2 production level to avoid warming.

This process addresses a different problem than electric cars do. It produces aviation fuel that is usable by existing long range aircraft. There is no battery powered alternative to an Airbus A330 or Boeing 777.

I address this in my comment though. CO2 is fungible, it does not matter what is producing CO2, all that matters is the net CO2 produced. If it takes 5000 units of solar power to produce 100 units of fuel for airplanes, it is completely stupid to do that when just not making the airplane fuel lets you take 5000 units of coal power production offline with no additional steps.

Saying it another way: If you use the 5000 units of solar or wind power to make jet fuel, that is 5000 units of solar or wind power you can't use to shut down 5000 units of coal power.

Let me break it down for you:

  Use solar to make jet fuel:
  5000 units of net CO2 from coal plant to make electricity.
  0 units of net CO2 from synthetic jet fuel.

  Use solar to make electricity:
  0 units of net CO2 from coal plant that isn't necessary because solar instead.
  +100 units of net CO2 from regular jet fuel.

Your hypothetical isn't actually happening.

Power generation dedicated to green fuel production is already being built in places that aren't readily connected to grids.

Further, we already curtail, for lack of demand and storage. More so over time. Better to use that excess power. Like for making green fuels.

Name a place there is significant power generation with no access to the grid? This is not a thing.

What if the 5000 units of energy were created from solar?

I think all these "generate something which can be buffered and stored" projects are interesting. A big problem with solar and wind is the transmission and intermittent nature. If the power can instead be stored as hydrogen for use in industrial processes or as jet fuel, that's great!

right, so use the solar to split hydrogen/oxygen from water and store it. hell, while you're at it, desalinate the water and burn the salt for more heat.

Burn the salt... ? :-D

Then you use the 5000 units of energy and just not make the co2???

I was thinking in chess moves so looking a few moves ahead rather than just what's in front of us now. Use this in conjunction with a CO2 extractor from the atmo, and now you're getting a 2-for-1 of the "clean".

No, your 3d-chess doesn't make sense. If you use the power to pull CO2 out of the atmosphere, then you don't have the power anymore.

No, you just put up another 5000 unit panel. Nobody said the same 5000 units had to be shared.

If you build an additional 5000 units then you could still use that to offset 5000 units of coal. You can keep doing this until there is no coal left. When there is no coal power, and no gas power, and no oil power, then finally you are right. How is this point not clear?

> Theres no scenario I can think of where it actually makes sense to use 5000 units of energy to clean up the CO2 generated by the production of 100 units of energy

This line of thinking comes from the fossil fuel industry. Nobody in clean tech advocates for this.

The problem is that even if we get to net zero by 2050, there will be too much carbon in the atmosphere. Global warming is actually suppressed by aerosols emitted by coal and other fossil fuels, and is going to get much worse even if we meet energy transition commitments. Further, there are industries that we don't know how to decarbonize (e.g., aviation, sustaining need for things like plastics).

Carbon capture (point source and direct air, whether for storage or for reuse) are logically sound. They are extremely expensive (thermodynamically, resource, $) and basically nobody likes them, but humanity lacks better solutions.

> well below the CO2 production level to avoid warming

The warming already happened and will continue to worsen.

We must reduce atmospheric CO2 to below 350ppm to stop, and hopefully reverse, the warming.

We need green fuels to hit net zero. And once the remaining use cases are decarbonized, we'll pump those fuels into the ground for net negative.

Good timing; I was reading today about Google X's project Foghorn, and wondering where we were (they shut it down with the coda that maybe in 5-10 years it would be more cost-competitive)...

I wonder if anyone has even analysed the carbon footprint of those big fans scrubbing CO2 from the air to find out if/when they'll ever even recover the CO2 spent building them.

Using green or nuclear electricity to create fuels to burn them seems to be a rather wasteful route. One can use in most cases electricity directly, save planes and oceanic ships.

The second peeve is with CO2 capture: while plants may not be the most efficient, they capture CO2 fairly cheap, as long as there is sun and water around. Heating biomass can give us biochar and bunch of compounds for downstream processing.

I wonder how this compares to engineered microbe based (synthetic biology) approaches. For example LanzaJet, a LanzaTech spinoff, produces Synthetic Aviation Fuel (SAF) that way.

Would be great if someone with inside knowledge could chime in.

It really, really doesn't matter what you make from the captured CO2. The main unsolved problem is capturing it economically. Then it's just generic feedstock for the chemical industry, but not until then.

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