Stripping CO2 from the air and using it to produce carbon-neutral fuel | Hacker News Reader

Stripping CO2 from the air and using it to produce carbon-neutral fuel

theguardian.com

120 pointsfold_left103 comments

Chemical engineer with experience in alternative fuels here. The key line is this:

"But for it to work, it will have to reduce costs to little more than it costs to extract oil today, and – even trickier – persuade countries to set a global carbon price.”

Their feedstock costs are probably quite low. Air, and from the sounds of it, water to produce hydrogen through electrolysis. They're probably then doing some combination of reverse water-gas-shift + Fischer-Tropsch to go from CO2 + H2 to diesel. Not unlike a similar project in Qatar using natural gas as their hydrogen source.

Problem is that carbon and hydrogen from methane is much cheaper than from air and water. Their electric/energy bill is probably massive, and also begs the question: could they fuel their plant with their own product and still have net energy gain? Or do they depend on cheap energy from more thermodynamically favorable fuels like coal and oil to be viable?

Solar, wind, nuclear, batteries, electric self-driving cars, next gen A/C, hopefully fusion someday... these are the energy or conservation technologies of the future, not something that's DOA because of basic thermodynamics.

The point of something like this is that, wherever we continue to use liquid fuels, it'd be nice if they were carbon neutral. Jet aircraft will probably keep using jet fuel for quite a while, for example.

But of course we'd need some kind of non-carbon energy source to make the fuel. Right now maybe we get the best bang for the buck by applying those sources to the electric grid, but with a carbon price the market would work that out.

I totally agree, imagine a country like Australia which has solar-rich land to spare. The efficiencies might not matter so much in exchange for a constant supply of easily-handled fuel.

Or maybe a nuclear-powered site which can convert CO2 into CxHy on an industrial scale. With the added advantage of removing CO2 in the process.

You also have the added advantage of not having to ship fuel in from chaotic regions of the world. Shipping produces a significant amount of the world's CO2.

The Navy is looking at doing this on their aircraft carriers to fuel aircraft as they have tons of extra electricity production.

Huh, that’s also a pretty major logistical simplification.

I wonder if they could also extract elements from seawater to assemble munitions. I used to think military spending was wasteful, but the technology is just too fascinating; I get a thrill just from thinking about it.

In 2008, LANL or ORNL published a paper on exactly that. I can't find my PDF copy, but they were suggesting making use of cheap electricity and waste heat from a nuclear plant to create carbon neutral fuels. ISTR they were calculating that it would be cost competitive with gas at $4 or $5/gallon. Probably not something we'll see in the US in the near future, but certainly possible in countries that levy more taxes on fossil fuels.

I believe that you're thinking of LANL's "Green Freedom" concept:

http://bioage.typepad.com/greencarcongress/docs/greenfreedom...

They estimated that it required a pump price of $4.60/gallon for gasoline to be economically viable, given their other assumptions. The authors assumed relatively low cost nuclear power from Generation III reactors. But the Green Freedom concept seems like it would also work with sufficiently cheap large scale renewable electricity production.

2.5% of global emissions are from shipping.

https://ec.europa.eu/clima/policies/transport/shipping_en

> could they fuel their plant with their own product and still have net energy gain?

I don't see how this is remotely possible. The synthetic diesel here is just a high-density energy storage medium. It's better than batteries because it's denser and compatible with the majority of today's engines. It's also denser than H2 (which is also just a store) and easier to handle.

But the plant here is not producing any energy, it's converting energy (probably electricity) into a form better suited for storage. Solar, wind, nuclear or fusion would be good sources of energy to convert into diesel, at most.

It all depends on whether their process is efficient enough to be worth it.

to simplify: this is a (potentially) carbon-neutral "liquid battery"

There's a competing technique that has net energy gain and better economics. It does require land and water, though.

> [CE's A2F] needs 100 times less land and water than biofuels ... but for it to work, it will have to reduce costs

Could you expand on net energy gain?

The process is driven partly by photosynthesis, rather than entirely by electricity.

Right, and there's an argument to be had that corn (or what have you) is a poor solar panel, but it makes up for it by being quite good at reducing CO2.

I think the research in TFA is very important -- I'm quite sure we'll be able to beat nature at this game in the long run and projects like this are how we'll figure it out -- but it's worth mentioning we have workable air-to-fuel technology right now but it has been largely abandoned because of the renewed supply of cheap oil.

I remember reading a website by a group of American researchers who had designed a plant, in some detail, where a nuclear reactor drove an atmospheric-CO2-to-gasoline reaction. The gasoline it produced was expensive, but not so expensive as to be completely absurd - a rise in oil prices and a fall in nuclear energy costs could make it practical. Needless to say, i can't find it now.

However, i did find this similar French work, which suggests taking advantage of the output from nuclear power plants at off-peak times:

https://www.sciencedirect.com/science/article/pii/S187661021...

> It all depends on whether their process is efficient enough to be worth it.

I don't see an estimate. But:

> The achilles heel of all negative emission technologies is cost. Government policy units assume that they will become economically viable, but the best hope of Carbon Engineering and other direct air extraction companies is to get the price down to $100 a tonne from the current $600.

I get that $600 per tonne CO2 is about 1.7 times the current global mean price of diesel. And $100 per tonne CO2 is about 0.3 times that. Given diesel-electric conversion efficiency of ~40%, you increase those estimates 2.5 fold. And then there's the energy input for hydrogen production, and the efficiency hit for chemical conversion.

It doesn't seem workable to me.

Using solar (or other carbon neutral energy sources) to make liquid fuel would probably be of great benefit for a couple of decades at least. Instead of everyone needing to replace their working cars with new electric ones, we can use hydrocarbons as energy storage. This will probably always be more expensive than oil, but where I live more than 60% of the final price is tax, so there's room for politicians to steer consumers towards carbon neutral sources if they became an option. Then there's airplanes, old classic cars, race cars, etc.

> could they fuel their plant with their own product and still have net energy gain?

That sounds like free energy / perpetual motion, i.e. physically impossible. Ok, there are inputs, but you don't expect the opposite of combustion to be a net producer of energy.

I think you're right in this case, but sometimes thermodynamically sound machines can seem like cheating at first glance. Heat pumps[1], for example, can have greater than 100% thermal efficiency (although they do rely on reservoirs of heat to do it). Another example is the vortex tube[2], which can separate a compressed gas into hot and cold streams with no moving parts (and relies on pressure to do it).

[1] https://en.wikipedia.org/wiki/Heat_pump

[2] https://en.wikipedia.org/wiki/Vortex_tube

Do you know how common heat pumps are in the US?

Obviously they have to put in more energy than they get out as per the law of conservation of energy. This is really not likely to compete well with batteries and EVs in terms of efficiency. Its only useful if the government distorts the market with incentives or where the energy density of the produced fuel gives an advantage over batteries (maybe if they produce jet fuel for planes?) I'm dubious that this could ever work for vehicles more efficiently than batteries.

One advantage would be if they can make fuel compatible with presently existing vehicles. Even twenty years from now, gas-powered cars are going to be common, just because gas-powered cars can last for twenty years and upgrading to electric faster than natural replacement is a financial and industrial burden. If you can make a car carbon-neutral while saving the [economic, industrial, environmental] cost of replacing it with an electric, that's a win.

Even in the long run, though- gas currently has something like a 100-fold energy density advantage over most batteries. It will likely continue to have uses long into the future.

To me that's a big loss. It seems pretty clear we're not fixing this quickly enough and need to go quicker.

A2F fuel is still hydrocarbon so will still spit out similar pollutants along with contributing to the associated health impacts. As the second half of the article notes it's far better not to have the pollution in the air in the first place.

What about the economic, industrial, and environmental cost of creating and running the A2F infrastructure and process?

In 10 years, probably less, most vehicles will have been replaced. Keeping internal combustion viable for +20 years will just avoid the issue and help delay the inevitable switch to renewables; be that electric, fuel cell, or something more exotic. Worst case scenario - in 20 years internal combustion is still pervasive, in part thanks to the adoption of A2F, with both fuels at the pump: oil sourced £2, A2F £2.10.

So in 20 years I sincerely hope gas powered cars are not common, and are fast becoming an occasional historic entertainment found in clubs, tracks and preservation societies. Rather like steam trains and horses have perhaps.

It could perhaps be very useful for aviation where renewables seem unlikely to make much impact any time soon.

A2F is unlikely to incentivize staying on fossil fuels- people burn gas because it’s cheap, and A2F won’t make it much cheaper in either case.

I would also note that for electric vehicles to be worth the bother at all, you also have to believe that the electric grid will be mostly renewable. And our current crop of coal plants will, sadly, last much longer than our cars, even if we stopped building them already (which we haven’t.)

I am also dubious. However, I could imagine this being useful as a way to balance out fluctuations in power supply from wind, solar, etc.

I think it could compete well, depending on the efficiency of the process. Advantages are that the energy density of liquid hydrocarbons is orders of magnitude greater than Li ion batteries, and likely always will be. So you can store a lot more energy in a smaller space. It's also easier to transport and distribute, since we have extensive infrastructure for transporting liquid fuels.

> This is really not likely to compete well with batteries and EVs in terms of efficiency.

The problem of EV is not their efficiency though, it's that they are extremely heavy for the range they provide, due to batteries still having terrible specific energy and energy density. And they basically only work in temperate areas (good luck running EVs in winter in Yakutsk).

ICE have much lower efficiency, but the sheer amount of energy in the fuel more than makes up for it.

And electricity storage at scale is still a problem we're nowhere near solving. Carbon-based fuels are extremely stable, if the generation process is not too lossy, they make for a pretty good storage medium: light, easy to manipulate, shelf-stable, and usable as-is.

"But for it to work, it will have to reduce costs to little more than it costs to extract oil today, and – even trickier – persuade countries to set a global carbon price.”

...or instead of reducing costs, just wait until oil increases past it.

It seems like a bet on the perpetually declining cost of solar. The cheaper solar gets the less efficient the conversion rate for storage needs to be to still be viable.

>could they fuel their plant with their own product and still have net energy gain?

Of course not, that would be the perpetuum mobile :) nor they claim that it can. Thing is, energy in form of liquid fuel is whole lot more expensive than in form of say, intermittent electricity from solar panels (which are now dirt cheap).

Slightly off topic, but here's a sweet tune named "Perpetuum Mobile" by the Penguin Cafe Orchestra (what I heard immediatley in my head while reading your comment).

https://www.youtube.com/watch?v=6E3znZoFnN8

Slightly off topic, but did you know that the Galapagos Penguin is the only species of penguin found North of the equator?

Completely off topic, but did you know that the North Pole is actually magnetically the Earth's south pole?

If you are prepared to sink capital into a low emission energy source, then once you have sunk that capital, its opportunity cost, not actual loss cost (absent running costs) to get the energy.

In the 'real' world, the fact that you are reducing the wind speed by some fraction, or reduced insolation thermal temps on the ground, and that if you scaled this to one million square miles: those 'it doesnt work' sums don't apply.

it doesn't have to be efficient, to be worth doing, if you are prepared to sink capital into a source of energy.

I doubt we can use batteries for long term storage of solar energy. Specifically, we need to stockpile in the spring and fall for the winter. That means we need to figure out how to make some kind of chemical fuel when sunlight is abundant and electrical load low.

There's an alternative approach: we could consider the cost-basis of fossil fuels, and whether or not that is appropriate.

It turns out that the basis and rationale (economic, legal, financial, actual) for the present regime are ... highly suspect. Hotelling's Rule is generally cited by is dismissed by virtually all parties as not describing reality (see for example BP's petroleum pricing data to 1859 in its annual survey of energy). The Rule of Capture is a legal justification for mineral taking that has no justification in the geological reality of the situation, a point recognised by some judges, though to date largely in dissenting opinions. Actual market prices are defined by the marginal extraction price, and in the absence of some cartel or regulatory body artificially constraining extraction rates (Standard Oil, the Seven Sisters, the Texas Railroad Commission, OPEC, Saudi Arabia), prices fall to absurdly low levels so long as there is any capacity to extract above current market demand (as with the $0.02/bbl prices of post-Daisy Bradford #3 oil-strike Texas in 1931, prior to the seizure at force of arms by the Texas and Oklahoma National Guards, and Texas Rangers, of wellhead production, and establishment of a quota system via "certificates of transport" for U.S. oil, and, by virtue of the U.S.'s status as global surplus oil producer, global oil markets, from 1931 - 1972.

If we consider the capital stock depletion to formation ratio of oil, which is on the order of about five million to one (years of formation consumed per present year), a fair argument might be made that petroleum and natural gas are very significantly under-priced.

A point at which other alternatives become far more viable.

(The situation is similar for coal, though the ratio imbalance is somewhat smaller.)

See: https://dge.carnegiescience.edu/DGE/Dukes/Dukes_ClimChange1.... (PDF)

Could they fuel their plant with their own product and still have net energy gain

No.

https://en.m.wikipedia.org/wiki/Second_law_of_thermodynamics

A few notes to help get this to the mainstream. Take these quotes:

* "persuade countries to set a global carbon price"

* "paid for by the emitters, or by the fossil fuel suppliers"

I think they should carefully examine how such efforts have failed or been sabotaged in the past. The issue most libertarians and conservatives have is not "co2 offsetting" itself, the issue is they don't like taxes and regulations because it interferes with individual liberties. From past experience, hinging an entire industry on a government-created market appears to be a sure path to failure. For all of the clever ingeniuty described here, I'm baffled why no one is addressing that, which seems to be the bigger issue.

The carbon tax (and cap-and-trade) is the right-wing think tank alternative to reducing emissions by regulation, much like the individual mandate/Romneycare/Obambacare/ACA is the right-wing think tank alternative to single-payer/Medicare for all/universal health care. The issue is that the right wing think tanks come up with these alternatives, and then the right wing labels them as a left-wing attack upon America.

I am surprised that "add carbon taxes, cut income taxes" doesn't take off. Income taxes distort the economy, so lowering them is a massive benefit - if they can be replaced with another, better revenue source.

A carbon tax is an infinitely better revenue source as it reduced externalities.

I think rather than focussing on emissions reduction, global climate talks should focus on a global carbon tax, offset by reductions in other taxes.

(It's somewhat ineffective for one country to do a carbon tax now. Past a certain point it will just send carbon producing activities to countries without a tax. A globally agreed tax reduces this.)

A tax would be the mechanism to reduce emissions. Absent such a mecanism, emissions have only grown, despite accords to reduce them.

Carbon taxes are regressive. I’m not disagreeing with your premise, but it makes them politically difficult. (Global warming will hit the poor the hardest too.)

Anyway, it is easy to make the carbon capture economy work, assuming you’re OK with instituting a fair carbon tax:

Give carbon capture plants 0.5 tons of carbon credit for each ton captured, and have the government sell unlimited carbon credits at 2x the market rate capturers charge.

I guess cutting income/corporate tax (could they even go negative?) could prevent this from crashing the economy, and let you adjust for the inherently regressive nature of fuel taxes.

Do credits have a good track record anywhere? My assumption is that the system will develop leaks and exceptions.

Taxes do have a track record of being applied successfully.

If regressivensss is a concern, you can either cut another regressive tax, or implement some kind of carbon dividend.

Yeah, regressiveness is easily overcome by dividing up the money among the population and giving everyone a constant income tax decrease – that way it's wealth transfer down, not up.

In case you haven't heard of it: Citizen's Climate Lobby [1] exists purely to advance this scheme, and is well worth investing your volunteering time into.

[1] https://citizensclimatelobby.org/

I should also add that if we don't solve this, we basically destroy the planet for all future generations.

"Marginal increase in regressive taxation load in the present" doesn't seem that bad, in that view. Though I do agree it affects the politics of it.

Of course, there's also the non-neglible social benefits of lower income taxes.

There's certainly a libertarian argument that pollution is the exact type of externality government should be solving given its tragedy of the commons in a way most things are not, as well as framing under core defense. I also imagine many would trade in the many other distortions for a simpler carbon tax scheme than things like funding Solyndra's which go bust.

Rothbard argues strongly that pollution is a property rights issue and an ancap/libertarian solution is fully compatible with all types of tort or financial solutions. Not to say a "carbon tax scheme" could be thought of as libertarian. But libertarian theory certainly addresses the externality issue of pollution.

What is a more libertarian solution than a tax? It's a price signal to the market to reduce consumption. I can't think of a more hands off approach. Everything else I can think of involves expanding beurocratic oversight and allowing the political class to choose winners and losers. To me the knee jerk anti-tax attitude of many people is a mental shortcut for people who don't have the attention span to actually think through ideology and economics.

Tell that to all the "content" industries whose business models depend on copyright and patent restrictions, aka government-granted monopolies. Or the transport industry that is already so dependent on government-provided roads.

> the issue is they don't like taxes and regulations because it interferes with individual liberties

It would entirely be possible to make a libertarian argument, because emitting CO_2 reduces the liberties of others. Thus it is important that the individual liberties of the victims of climate change are also considered and be considered as if it was property.

Since reassigning property rights on a global (public) good don't work well, a (Pigouvean) tax seems like a sensible thing to preserve individual freedom of everyone.

or stockpile it

Legit question here, not snark. How could this possibly be better than something like an algae based biofuel? Have self-replicating, solar-powered machines do the CO2 extraction and reduction work on their highly specialized membranes. Then use the product? I get that this sounds fancy, but I'd be surprised if they can be even close to energy neutral pulling power from the grid to reduce the CO2 into hydrocarbons. At best, their plan just externalizes the carbon cost to the generator infrastructure (which could be renewable, sure, but again: plants are solar-powered as well).

AIUI, getting algae to scale is a big problem. Not 'nuclear fusion' hard, but difficult all the same. We've got more experience with mechanical and chemical processes at industrial scale, so this is easier.

I've only looked into this a little bit, but I think one problem is that you're limited by either nitrates or phosphates, depending on whether the algae are being grown in ocean water or fresh water. Either way you have to supply some kind of nutrient, which has to be either mined or synthesized in some energy-intensive fashion.

Could you recover those nutrients when you convert the algae into diesel?

Scale and parasites.

Algae are, at best, about 10% efficient at converting sunlight to fuel.

To meet present U.S. petroleum neds, you might, say, put grow ponds on the east and west coasts.

They would have to extend 1500 miles north-south and be about 60 miles across.

That is an ambitious project, to put it mildly.

Then you'd need to fertilise the ponds, drain effluent, and keep anything other than you (or your fuel harvesters) from munching on all those gigajoules of hydrocarbon energy.

Fisher-Tropsch seawater-sourced synfuel would reqire a few square km of plant, and roughly 180 miles squared of solar power feed.

In a world of grossly intractable fuel / energy alternatives, that's not completely beyond reason.

https://www.reddit.com/r/dredmorbius/comments/22k71x/us_navy...

Algae based biofuels need a lot of land. This process uses less land.

So much managed tech for something nature already solved for us passively. I think if we just changed where and how some of our basic input and outputs go we could solve this without any tech.

https://halfhillfarm.com/2017/04/21/how-hugelkultur-can-help...

Your article says that could absorb a third of emissions, which is great. But it'd be even better if we did that and did everything possible to reduce our emissions.

Not even a third of emissions - 30% of the increase in emissions. And, I don't see the calculation, but it surely can't be done just from the carbon in people's backyard gardens.

I could if more people did it instead of loading branches and logs onto trucks and going into the waste stream they can be used on the same property, sunk into the ground and left for 20-30 years. It requires changing how people deal with outputs.

Decomposing plant matter creates C02 and methane, so Hugelkultur only suquesters carbon for short periods. Biochar, a.k.a. terrapreta which is buried wood charcoal, on the other hand is thought to be inactive in the soil for closer to 10k years.

One can combine energy production from wood gasification, which produces char-ash and biochar to produce a carbon negative electricity source. Taking this a step further one can use the Fischer–Tropsch process on the resultant syngas to produce liquid fuels.

It sequesters it for 10-30 years and then the plants and trees that are grown on or near it further sequesters CO2 and carbon.

I think of composition as a "slow burn" (merging back with air). Also creating bio-char is a pain in the ass and not passive at all.

One benefit of biochar is that it anecdotally increases soil fertility, so maybe you could produce more bio diesel while you are at it.

The IPCC scenarios, which are already grim, also include hypothetical forms of carbon capture that do not yet exist, in addition to drastic emission reduction, to prevent the Earth from becoming a disaster in the next 50/100 years. This report has a good overview of the difficulties with current carbon capture plans. https://easac.eu/fileadmin/PDF_s/reports_statements/Negative...

One of the huge pluses of electric cars (besides the obvious elimination of humanity-threatening climate change gases) is that cities will be less choked with car exhaust smog. Living in a major US city, whose air is quite clean compared to many other places in the world, still means you get exposed to constant facefulls of car exhaust, truck smoke, and particulates every time you set foot outside.

That's not healthy on a direct human level, let alone a climate change level. We're at the cusp of getting rid of this miserable pollution completely, and maybe even having truly clean air in our major cities, in our lifetimes--why invent a technology to allow us to keep the smog and particulates around even longer?

Because there is no near or medium term solution to the exhaust from shipping, which is what this invention is targeting and which comprises 1/3 of the climate change causing emissions.

Perhaps not a solution, but wind assist [1,2] for shipping seems like a way to chip away at that problem.

[1] https://en.wikipedia.org/wiki/Wind-assisted_propulsion

[2] https://en.wikipedia.org/wiki/MS_Beluga_Skysails

Multi-pronged solutions are needed for this massive issue. We need to avoid emissions where we can, switch to clean energy where we can, and use clean-up technologies if they do become energetically feasible. And keep in mind that just planting more trees or preserving existing rainforests can also go a long way. In the end doing something is better than coming up with endless roundtable resolutions and pledges that are then universally ignored.

The obvious problem is that too make enough gas to power a gasoline car, you'll need to spend more energy than it takes to charge a Tesla (likely many times more, I'm not sure what the energy efficiency of the conversion process is).

I do have a fantasy that if we had an abundance of fusion energy (or just nuclear, perhaps), you could not only power cars, but also make oil from co2 and put it back where it came from.

If the energy is "free" (wind or solar) the efficiency matters a lot less.

That's a bit of a weird idea.

CO2 is not present in fairly high amounts in the air, using some quick math, I would estimate that for 1kg of CO2, one would need to filter over 2.5 tons of air (Though if we keep pumping more CO2 into the air, this will become more efficient). The energy required to do this won't be trivial, so it would have to be from renewable resources. Why not use those directly?

I would suggest it would be more efficient to draw the water from the air and produce hydrogen, which is a clean fuel unlike carbon (which just burns into CO2 again, under normal conditions). And if you run out of water to pull from the air, you can probably find a bit of water on this planet to use, it's not like we want a rising sea level (though it's unlike we will impact the sea level by pumping out the water and turning it into hydrogen fuel)

And as I just mentioned, the CO2 you just pulled from the air will burn straight into CO2 again, in fact, it'll burn into the exact same amount of CO2 (assuming clean combustion), so it's just a very inefficient battery...

[repost from dupe, original deleted]

Using electricity directly is fine for a lot of applications. Synthetic liquid fuels are a very inefficient, very dense "battery" that you can drop right in to a trillion dollars' worth of existing fossil-powered machines. Hydrogen is (IMO) the worst of both worlds for most applications: much less efficient than battery electric systems, but can't be a drop-in fossil fuel replacement for existing airplanes/trucks/bulldozers either. Converting to hydrogen makes you pay for accelerated replacement of existing capital stock plus the inefficiency of storing energy as fuel.

I think it's intended as a way to (soft of) economically build out carbon capture infrastructure. At some point these facilities could transition to providing hydrogen fuel and C02 sequestration.

Even if there is no carbon price, the idea could work if - and that's a rather big if - the cost of making "oil" from air with CO2 and water can be made low enough.

We might look into energy efficiencies along the process and into energy efficiencies to make those energy efficient components of the factory. Yes, it's far from closing economically or even energetically today. Will it always be so?

However, another aspect seems to worth attention here. It seems rather inefficient first to have cars which make CO2, release it into - rather big - atmosphere, then spend efforts to capture CO2 from that. But this approach - let's pump all the air of the planet through purification devices - allows to do other things, not only capture CO2. How about extracting noble gases (it's already done, AFAIK)? Or other greenhouse gases, like methane? Or ozone-destroying substances? May be we can engineer our atmosphere to our tastes? May be we can use those technologies elsewhere - say, on Venus?

The concept of generating synthetic fuels from biospheric sources of CO2 is not new. And atmospheric CO2 may not be the most sensible choice: costs for sequestration from seawater (measured in energy) are much lower.

I'd become somewhat excited by the potential of seawater-based Fischer-Tropsch fuel synthesis about four years ago after a set of articles from the U.S. Naval Research Lab were published. I was shocked several ways to learn that the concept was far older -- both because I'd been unaware of the fact, and that the NRL's own publications failed to cite the pioneering work in the field, from Brookhaven National Labs, in 1964 (by Meyer Steinberg). The original concept was suggested by M. King Hubbert, of "Hubbert Peak" (peak oil) fame, in a 1963 paper.

I've compiled a set of early research from Brookhaven, M.I.T., and NRL:

https://www.reddit.com/r/dredmorbius/comments/28nqoz/electri...

On the positive side: the research is solid and there's ample history. On the negative: there's been very little actual proof-of-concept and virtually no scaling of the concept. This suggests potential engineering challenges.

Otherwise, the basic size and energy budgets are within reason, contrast biofuels, which in virtually any configuration simply does not produce enough viable fuel to sustain modern energy budgets. See:

https://www.reddit.com/r/dredmorbius/comments/2cvap7/the_int...

The acreage requirements alone approach or exceed the total land area of the U.S., in more conventional cases. In the case of algae, this is reduced to "only" virtually all current agricultural acreage.

Hubbert's suggestion: http://www.hubbertpeak.com/hubbert/EnergyResources.pdf

Steinberg's obituary, from 2015: https://www.newsday.com/long-island/meyer-steinberg-of-melvi...

Beyond any greater dialogue about the relevance of this tech, at any scale, in mitigating our impact on the climate, I simply like the idea that this allows for local creation of hydrocarbon liquid fuels in remote locations.

Given the amount of energy required to shift energy around the globe, it makes sense to develop systems that can act independently of the greater fuel economy. It also (I think?) allows us to keep using existing ICE tech for years to come, which no matter how utopianistic one gets about electric drives, is an insurmountable reality.

This is a crazy scheme. If you want CO2, there are much easier places to recover it than from AIR. Flue gas of furnaces/boilers, chemical plants that make it as a byproduct, etc.

Worse, their whole plan needs a source of hydrogen, which they claim will come from green energy electrolysis - but the math doesn't work well. You'd need nuclear reactors or big hydro dams to make enough to make fuels at scale.

And it won't be carbon neutral because of the second law...

So... Wouldn't burning wood meet the headline?

Yeah, and since coal is dead biomass one would think we can burn that too. I suppose it's possible that billions of years of moss growing on rocks has produced a lot of that biomass, and that it was never all in play at once. But people generally get pissed and defensive when I mention the coal thing. I've never had anyone even attempt to refute the idea that coal is carbon-neutral in scientific manner. That's what makes it so much fun to say.

> I've never had anyone even attempt to refute the idea that coal is carbon-neutral in scientific manner.

Except maybe nuclear, no source of energy creates new carbon. The question, vis-a-vis carbon neutrality, is "over relevant time scales, does this leave more carbon in the atmosphere (as opposed to sequestered in oil, coal, trees, whatever)?" If you create coal and then burn it, that's carbon neutral (modulo whatever you produced creating the coal). If you dig ancient coal out of the ground and burn it, that's not carbon neutral.

>> If you create coal and then burn it, that's carbon neutral

Right, there was no coal when the earth formed. It's all former biomass and was part of the biosphere. So we need to burn it to actually be carbon neutral. I did offer a refutation of this...

You are (willfully?) ignoring my point about time-scale, which your offered refutation doesn't address.

Yes, of course the coal hasn't existed forever, and before that the carbon was presumably part of the atmosphere. But that wasn't an atmosphere ever breathed by Homo Sapiens. We don't want to make sure the atmosphere matches that at earth's creation (it wasn't always even significantly oxygenated! and if we want to put back all the carbon that includes killing all life). We want to be sure our activity doesn't leave us with significant negative consequences.

My refutation was that the carbon may have been part of the rocks which the mosses and lichens may have gotten some use of. And of course that would be over an enormous amount of time, in which case burning the coal too fast would bring up more at one time than has ever been around. I don't recall what they say the primordial atmosphere was like, and I don't advocate going back to that. I do suggest we look back prior to the ice age (periodic glaciations 10-15Myr) and not worry if we replicate those conditions - there was apparently a lot more life on earth back then, and plants at higher latitude.

The most recent ice age (I think it was the most recent; it was fairly recent) was brought on by runaway warming of the atmosphere by CO2. This led to disruption of ocean currents, which caused glaciation at low latitudes.

It took 50-100 years for the glaciers to form. Global warming caused measurable disruption of the same ocean currents in 2016 and 2017.

So, replicating pre-ice age conditions, as you suggest we should, could easily lead to the collapse of most European states, and at least the northern half of the US.

If you want to go back to the climate Earth had before the carboniferous era, then sure, burn all the coal. However, I'd suggest doing it over a period of a couple million years to give the biosphere time to adapt back to global rainforests.

The term "carbon neutral" refers to the amount of carbon active in the ecosystem. It excludes sequestered carbon in underground deposits (coal, oil).

If the term "carbon neutral" referred to all carbon on earth, then yes, burning coal would be carbon neutral. But that isn't what the term means.

Your idea is refuted by definition, not by science.

Coal used to be carbon active in the biosphere. Oil did not - at least going by a commonly accepted theory of oil forming deep in the earth. The question remains - if coal was sequestered, what were things like prior to the sequestration?

The same holds for the methane that's starting to be released as the permafrost in the arctic thaws. That used to be active in the biosphere, so why should it be a problem?

We don't want to go back to those levels of carbon in the atmosphere. Doing so would completely disrupt every ecosystem in the world. As pointed out already, carbon neutral refers to a time scale that is in the order of at most a few decades. Anything longer than that would have severe ecological effects.

That's not a great argument the earth used to be ball of magma with no solid surface why should it be a problem if we return to that?

I'll try - just from my general knowledge; no claim of authority!

1) Coal; coal is a case of carbon sequestration. Coal was largely formed in the Carboniferous period, at this point plants had evolved to form wood which uses lignin in its structure. This allowed forests to form, but until the end of the Carboniferous fungi that could degrade and decay lignin were no widespread. This led to a bloom of oxygen in the atmosphere and a crash in carbon dioxide. The earth cooled and there was a mass extinction. Lignin decaying fungi then became widespread releasing the non sequestered carbon (that which hadn't formed into deep deposits of coal) from the lignin. In the carboniferous period the carbon from many 100's of millions of years of volcanic activity was sequestered by plants in coal deposits, since then the ecosystem has faced the need to absorb a smaller amount of carbon from just 300 m years of the volcanic history of the earth. This has resulted in the chemical balance of the atmosphere and oceans we have today, including the way that they interact with geology.

2) Methane in permafrost; I think that this is a much smaller amount of carbon, but the problem is that the iceage processes that have formed these deposits have resulted in a store of methane, rather than CO2, and methane is a very strong greenhouse gas. Injecting a large amount of methane suddenly could lead to a sharp period of warming.

Before coal formed the chemistry of earths oceans and atmosphere was different; there was sulphur in the water column of the oceans. Carbon dioxide was ~8 times the current level. The world was 6' C warmer, and at that time Sol was ~5% dimmer. Sea level was ~170m higher than now, and the seas would have been very acid - due to the carbonic ions.

Going back to a world like that wouldn't be a problem, for some bacteria, for animals with shells or bones, well - not so good. In fact, there probably wouldn't be any because the acid in the ecosystem would prevent calcification - rubber for bones! Expect worms, leeches, jellyfish and insects to profit.

This time round there will be no carboniferous swamps - fungi have the trick of decaying wood now, so the time of large animals on earth will be done, back to the Precambrian, but hotter, polluted (for a million years at least) and radioactive (for a bit longer).

The permafrost past/future is probably more benign; 70 -100m of sea level rise, some acidification - but nothing like enough for the end of skeletons. I think it would likely see a massive reduction of human population, but I doubt that humans or human technology would disappear.

I hate when they confuse CO2 extraction with "cleaning the planet". Such popularizing/oversimplifying is irresponsible! These are two completely different things; clearly someone who submitted this to HN understood it too when adding the title.

How about planting more trees? Cannot think of a more efficient process of removing CO2

Hectares to tonnes, peat bogs might beat trees, but generally I'd think biology has the edge here.

Nature already developed this technology: trees.

More seriously: perhaps it's not such a bright idea to build a for-profit industry on the concept of removing CO2 from the atmosphere. Plants need it and if we overdo it for the sake of maximising profits, the ecosystem will suffer (alarmism: we'll all starve).

Just plant more trees, please.

It gets burned and goes straight back into the atmosphere. It's carbon neural, not carbon negative.

> It's carbon neural, not carbon negative

What does the headline of this thread say?

> Stripping CO2 from the air and using it to produce carbon-neutral fuel

So, where's the benefit over trees? The drawback is that the fuel doesn't have any uses other than to burn it for energy. Trees, on the other hand, just suck up increasing amounts of CO2 while they grow and they don't have to be turned into fuel.

You missed the headline apparently since you were commenting about the dangers of sucking too much carbon dioxide from the atmosphere. Clearly if it's carbon neural there's no danger of that happening.

Trees are also carbon neutral since they either burn or decompose and return the carbon to the atmosphere. But over much longer timescales than fuel - so they could still be useful in combating global warming (despite what some people say.)

In particular, if you increase the average global biomass over time, then you’ve captured some carbon.

Longer term, you can bury that biomass instead of burning it or letting it decompose. Eventually, it will turn back to oil. I guess the question is whether these new technologies are better than buying up tree farms and sending their outputs to landfills at are optimized to minimize decomposition.

Edit: Tree farms are a terrible straw man. Are these technologies better than simply instituting bio-waste bins alongside recycling, and burying the bio-waste for long term carbon capture instead of composting?

The benefit is that you don't need huge amounts of land, can use surplus energy in a useful way and produce something that is of immediate value.

What is "burning wood" Alex?

You might want to see your Doctor

Nature already has this technology. Plants & Trees. Plants & Trees have numerous other advantages compared to Bill Gates' solution:

* They are less expensive

* They don't require a technological infrastructure, meaning 3rd world countries could easily deploy them

* They require little to no maintenance

* They promote life & ecosystems

* They have been tested in the field for hundreds of millions of years

* As CO2 increases, plants & trees grow & consume more CO2. A positive feedback loop!

Plants & Trees are a far superior solution. We should spends billions of dollars on more plants & trees.

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