
Sucking carbon dioxide from air is cheaper than scientists thought - kjeetgill
https://www.nature.com/articles/d41586-018-05357-w
======
maxander
Remember that, _a priori_ , you should be far more skeptical of studies with
this sort of result than, say, studies showing that neocortinoids don't harm
bees or that the latest blockbuster pharmaceutical has no side effects. The
sheer mass of money in position to lobby for the "fossil fuel use is fine!"
position dwarfs that of all other financially-fraught research questions put
together.

To wit; the company behind the paper in question, Carbon Engineering, is noted
by Wikipedia as having "oil sands financier N. Murray Edwards" as one of it's
principal backers. And the article's "outside expert's opinion" quote comes
from Stephen Pacal, co-director of the Carbon Mitigation Initiative at
Princeton- which has an "extended partnership with BP" worth a great deal of
money [1]. The financial conflicts behind this research are _staggering_.

[1] [https://www.princeton.edu/news/2010/11/18/carbon-
mitigation-...](https://www.princeton.edu/news/2010/11/18/carbon-mitigation-
initiative-receives-11-million-through-extended-partnership-bp)

~~~
zzzeek
this is kind of interesting as there's some reverse/upside down ideas that
come out of it:

1\. the big oil companies and the massive political machine that supports them
drops the whole "global warming isn't real" line, no more snowballs being
taken in to congress and all that. Because now they can just say they'll suck
it out of the air and they can continue to think they can keep burning all the
coal and oil they want (which of course they should not). Once everyone is on
the same page that global warming is real, they can't go back on that. If the
approach here proves to be insufficient (which it probably is), a lot of
political points have been scored in any case.

2\. the machinery to suck out the CO2 is another big "green" industry, like
solar or wind, but _doesn 't_ compete with oil/coal! it's meant to mitigate
the damage they do. So as you've noted, way more money and attention might end
up going here, increasing the chance of its viability.

3\. No matter what happens with the rate of burning oil/coal, we _need_ this
anyway. There's consensus that we're pretty much over the point of no return
with warming due to all the ice that has melted, and if the permafrost goes
that might be catastrophic.

~~~
briandear
Is anyone actually debating if climate change is happening? The debate is on
the degree of human influence.

~~~
Consultant32452
During the last ice age there is evidence that suggests the Earth's
temperature rose 10-15 degrees in less than 10 years. In fact, during the last
110k years represented in the Greenland Ice Sheet Project the climate shifted
dramatically multiple times over periods of a few years to maybe a couple of
dozen years. During the last 110k years the most stable has been the last 11k
years, which is kind of just dumb good luck for us living today.

Current anthropomorphic climate change models suggest we might see 2-3 degree
changes in 100 years. I believe the science is likely accurate here. I support
moving towards renewables and just about anything else generally supported by
the climate change crowd. However, I think the panic button has been pushed a
little too hard on this issue. I think things like overfishing the ocean and
even plastics in the ocean are going to be bigger problems in the short run
than human caused climate change.

Generally speaking this kind of nuance isn't allowed. The kind of response
that says "If water rises a few feet, move a few feet inland, you've got a
century of notice. If you have to farm over there instead of over here, then
farm over there instead." is sacrilegious. To many, I would be considered a
"climate denier."

~~~
linkregister
The economic impact on the United States alone will be in the trillions.
Relocating all of Manhattan, Toronto, London, Singapore, and other coastal
economic centers is non-trivial, but would hopefully be gradual enough to be
viable. It would be fantastic if we can avoid this loss of wealth by making a
meaningful reduction in the rate of global warming.

Other nations are already experiencing famine due to permanent
desertification. This has already exacerbated political and military
conditions; drought is a major factor in the Syrian and other war zones.

To compare this to the range of human history is not meaningful. "They had it
worse" isn't helpful for now. What matters is our response to the conditions
that we are expected to experience.

Around the 120,000 BCE time, there was a "great filter" event that caused the
mass death of most of humanity, causing a massive reduction in human genetic
diversity. Yes, we may have it "easier," but today's problems are still real
and must be dealt with.

I think it's useful to frame the climate change process solely in terms of
human impact, and specifically economic, political, and security terms to
governments.

I wouldn't consider you a denier, and it's important to share your
perspective. I hope you consider mine.

~~~
roenxi
The cost of the Iraq war is in the trillions. A cynic could argue that that
war happened to secure burnable fossil fuels.

It isn't obvious that the cost being in the trillions is cause to blanch - at
the scale we are talking, the cost of mitigating with more expensive energy is
also likely to be in the trillions.

You might benefit from being more specific about how many trillions.

------
pier25
Doing a little math...

Considering 1100 Gtons in the atmosphere and $200 per ton would be roughly
$220 trillions.

The current world's GDP is $78 trillions.

Even if the world invested $10 trillions every year it would still take 20
years to remove all the carbon emitted between 1850 and today.

Of course we would keep pumping about 37 Gtons per year (and growing).

[https://www.carbonbrief.org/analysis-global-co2-emissions-
se...](https://www.carbonbrief.org/analysis-global-co2-emissions-set-to-
rise-2-percent-in-2017-following-three-year-plateau)

~~~
dietdrb
This industrial approach to carbon dioxide removal is but one of several in
our toolkit, and by no means the least expensive.

Project Drawdown ranks every approach in terms of tonnage of CO2 and cost.
[http://www.drawdown.org/solutions-summary-by-
rank](http://www.drawdown.org/solutions-summary-by-rank)

These approaches get amplified by a price on carbon. If you are interested in
convincing your Member of Congress to price carbon, take a look at the most
effective organization doing this work:
[http://www.citizensclimatelobby.org](http://www.citizensclimatelobby.org)

~~~
Double_a_92
Sure... educating specifically only the girls is #6 on the list.

Why would they have to bring feminism into that? I mean sure, it's a good
thing to educate everyone. But why mix it?

How can I trust all the other points on the list now? What if they are also
just pushing some other political agenda?

I can't. They just compromised the list's integrity by that.

~~~
rootusrootus
Did you read that section to see why they think it'll help? It doesn't sound
like politics to me.

~~~
Double_a_92
Yes I did. Because educated people have fewer kids... Might be true, but what
kind of reason is that even!?

Why not also establish a one-child policy in western countries? Or start
actively killing sick people? /s

All the other reasons were basically how it makes lifes better for those
women. Which is surely a good thing, but doesn't matter in that context.

------
advisedwang
Apparently burning petrol releases about 2.31 kg of CO2 per liter. At 100 USD
per tonne of CO2 it would cost 0.23 USD per liter of petrol if we captured
every bit of CO2 released. That's within the realm of possibility.

~~~
lifeisstillgood
Well that's a Holy Fuck moment for me.

I thought the parent here had made a off-by-orders of magnitude error - how
can a liter of petrol (which itself is only a kg) produce 2.31kg of CO2 ... i
mean work it out, all the carbon would have to attach to 2x oxygen ... ok that
might just ... err ...

see this reference for a walk through of the calculation -
[http://ecoscore.be/en/info/ecoscore/co2](http://ecoscore.be/en/info/ecoscore/co2)

Every time I pour petrol into my tank I am basically pouring twice that
_weight_ of CO2 into the atmosphere.

I may be very dumb but I never thought if it like that before. I always
assumed CO2 was a minor byproduct ... but like breathing.

oh dear.

~~~
voidmain
> like breathing

When you eat 1kg of peanut butter, if I've done my math right, you'll breathe
out about 2.3kg of CO2. Dry cereal would be about 1.5kg. Most foods have a lot
of water in them, though.

~~~
dTal
I would think you're unlikely to produce sufficient bile to metabolise an
entire kilogram of peanut butter at once. Most likely you'd get really nasty,
oily runs at best, and quite possibly throw up.

------
08-15
So they are talking about a plant, soon to be built, that will capture about
50.000 tons of CO2 per year. Amazing! A single coal fired power plant (1GW)
emits 12 _million_ tons of CO2 per year.

Seriously, this stuff won't work, and it's pointless as long as fossil fuels
are burned somewhere on Earth. It's bloody obvious what to do instead: (1)
stop burning coal for electricity, (2) stop burning methane ("natural" gas)
for electricity, (3) stop burning methane for process heat, (4) stop using
methane to make fertilizer, (5) use electrified railways instead of trucks for
most transportation.

 _Then_ it makes sense to talk about synthetic fuels, CO2 capture,
electrifying the remaining transportation, etc, but not before.

~~~
rvail2
Pointless? I wish I could back through history, and count how many times
"experts" said certain ideas and endeavors were "pointless" just to have them
become reality.

~~~
thereisnospork
Just make sure you also tally up how many times they said 'pointless' and were
proven right.

Spending time and resources on things that won't work (economically) does no
one any good.

------
kjeetgill
Substantial conversation on reddit:
[https://www.reddit.com/r/science/comments/8pbuqv/sucking_car...](https://www.reddit.com/r/science/comments/8pbuqv/sucking_carbon_dioxide_from_air_is_cheaper_than/)

~~~
tptacek
The r/science conversation crushes the HN conversation and is worth skimming.

------
Tloewald
Let's take this article at its word, which is that right now we can bury
carbon for $600/tonne (forget the speculative $100/tonne) which equates to
$1.32/liter of gas (based on the speculative $0.22/liter). In California right
now gas costs ~$4/gallon (which is high compared to most of the US but low
compared to most of the developed world), so it's not an insane amount to pay
for carbon-neutral gas.

The interesting thing to me is that this is presumably something _ideal_ to do
with excess solar power (e.g. it's a much better deal than paying other states
to use it, which is what California is currently doing).

Another question is how does this compare, price-wise, to using solar power to
create fuel (e.g. hydrogen) and truck it around the way we do with gas.

------
dumbneurologist
All of the skepticism here in the top comments is well-placed.

This is basic thermodynamics: if you can burn fossil fuels to get
energy/electricity, then putting the CO2 byproduct back into an inert form
will cost exactly as much (or _more_ ; courtesy of the second law) as it would
have to get that energy from a different source in the first place.

There is no technology - now or ever - that will make "scrubbing" CO2 more
economical than simply leaving the oil in the ground, and using renewable
energy sources.

~~~
Zenbit_UX
Physics and thermodynamics don't actually use $ costs in their equations... e$
!== mc2

The costs you are referring to are in energy. It's entirely possible that the
$ cost to put it back into the ground are cheaper than to get it out.

~~~
AstralStorm
Hmm, mostly depends on where you put it. Putting it into ocean would probably
be add hard as getting it out of there.

Except here we can put it into storage in a more convenient place.

The real problem is that we do not have enough energy to run this yet. A bunch
of nuclear plants would solve it but these come with political baggage.
Unfortunately CO2 recovery is very local.

------
lastUsername
"The Paris Agreement’s inclusion of 1.5°C has catalysed fervent activity
amongst many within the scientific community keen to understand what this more
ambitious objective implies for mitigation. However, this activity has
demonstrated little in the way of plurality of responses. Instead there
remains an almost exclusive focus on how future ‘negative emissions
technologies’ (NETs) may offer a beguiling and almost free “get out of jail
card”. This presentation argues that such a dominant focus, evident for 2 and
1.5°C, reveals an endemic bias across much of the academic climate change
community determined to voice a politically palatable framing of the
mitigation landscape – almost regardless of scientific credibility."

Please read: [https://kevinanderson.info/blog/duality-in-climate-
science/](https://kevinanderson.info/blog/duality-in-climate-science/)

The problem here is cultural, not scientific.

Real science about climate change is not politically palatable, NETs represent
an easy way out.

~~~
frockington
And if we were trying to do real science we'd have to actually find proof of
cause and effect. I still have yet to find convincing proof that CO2 is the
culprit. Te level of CO2 in the ar should be addressed, but I am worried that
we have culturally painted CO2 as such a bad guy that the underlying cause of
global warming will never be found

------
danschumann
The problem of climate change is the same as the obesity problem, if you
phrase it like this: "There is something that is going to kill you in 20 years
if you don't change your habits today".

Most people wait until they have a significant event (heart attack, they can't
get up the stairs without being out of breath, etc) until they change.

I always figured it would take some sort of big event for people to change,
and then when that happened, we would start working on retroactive fixes (
like sucking co2 out of the air ), rather than preventative fixes.

------
fallingfrog
The thermodynamics of this seems wrong to me. You would have to burn at least
a ton of oil to draw a ton of carbon from the air, probably more like 2 tons
due to inefficiencies. The cost of oil is 418 dollars a ton. So to make this
even remotely plausible you have to assume access to an energy source which is
4 times cheaper than oil on a cost basis. So cheap, in fact, that unburning
carbon from the air would be twice as cheap as mining it out of the ground.

~~~
RockyMcNuts
hypothetically, if you burn 2 tons of oil and you get out of the atmosphere 1
ton of oil equivalent to burn, then if your emission-free energy cost is 1/2
the price of oil, you break even on cost, and reach carbon neutral, no?

Alternatively, if your emission-free energy cost is same as oil, you tax oil-
based energy 100% and now you reach carbon-neutral?

I don't see why it has to be 4x cheaper, clarification would be helpful.

~~~
DoctorOetker
he's estimating the energetic i.e. objective cost. If the government
subsidized to the point of us stopping pumping up oil or true fossil neutral
rate (ignoring the CO2 already up there, which will over hundreds of years
fall back to natural levels), then we would have to manufacture our fuels...
with what energy? sure in the long term I think we can use renewable, but it
isn't deployed yet. The only way this makes sense is if we deploy true
renewable energy, and stop allowing fossil fuel industry to masquerade as
green.

------
selimnairb
Unless we stop burning fossil carbon, pulling carbon out of the atmosphere to
create fuels that we will then burn makes zero sense, in terms of mitigating
climate change; even if we used solar energy to do this, there would be no net
decrease in carbon in the atmosphere. This only makes sense if we use a
carbonless energy source and “permanently” sequester the carbon somehow.

------
theptip
> The result, after further processing, is a calcium carbonate pellet that can
> be heated to release the CO2. That CO2 could then be pressurized, put into a
> pipeline and disposed of underground.

I'm curious why you wouldn't just bury the calcium carbonate pellets at this
point (or sell them, since they have value). Pumping CO2 underground isn't a
cheap or reliable process yet as far as I can tell.

> the company is planning instead to use the gas to make synthetic, low-carbon
> fuels.

I suppose the answer is that the synthetic natural gas is more valuable than
the calcium carbonate. Seems like adding more steps than strictly necessary
though.

Edit:

> In the United States, Carbon Engineering is eyeing a recently expanded
> subsidy for carbon capture and sequestration, which could provide a tax
> credit of $35 per tonne for atmospheric CO2 that is converted into fuels.

Missed this bit in the article. Regulatory arbitrage, which is a very good
reason to add another step in your process, even if it's not strictly optimal.

~~~
codefined
I haven't done chemistry in years, but I think you can fairly easily reuse the
calcium carbonate pellet once it has been heated. I imagine the cost of energy
is significantly less than the cost of the raw resources.

------
hmwhy
Economics and policies aside, I’m a bit skeptical about the approach described
in that article regarding the use of potassium hydroxide (production,
transportation) and it’s subsequent processing (to re-release the captured
carbon dioxide, somehow transform it into fuel, and let people release
again!?); even just the logistics would most likely be releasing a good amount
of CO2 if cost is such a huge factor in this.

It just __feels __like the carbon dioxide released would be a substantial
offset to that captured. Ultimately, it would still be viable if the net
outcome is a reduction in atmospheric carbon dioxide; but I’m not convinced,
at least with the approach in question, that humanity’s interest is at the top
of the list.

It would be absolutely fantastic and very much appreciated if someone who
knows about the actual “accounting” of carbon dioxide in this type of carbon
sequestration technology can comment.

------
AtlasBarfed
Soooo, around $100/ton.

And google says we currently pump 40 billion tons per year.

Let's ballpark:

average 5 billion per year for 100 years.

500 billion excess tons.

50 trillion dollars to remove what we've already polluted.

\+ 4 trillion per year to offset what we're at already.

Yeah, nothing about that is "cheap". Maybe... slightly less astronomically
expensive.

And a lot of cheap carbon capture is "pump it into the ground", which, while
I'm not a geologist, but I'm guessing the petroleum folks aren't looking to
hard for leaks back into the atmosphere.

But given those numbers, greening the sahara seems like a much better approach
than any industrial approach.

------
ajnin
Based purely on numbers CO2 capture seems like a plausible idea. The article
cites a cost of $0.22 cents per liter of fuel to capture an equivalent amount
of CO2. Based on the current 93 million bbl or roughly 15 billion liters of
oil consumed every day worldwide, the cost would be around 1.2 Trillion USD
per year, or 1.5% of the global GDP. A lot but within the real of feasibility.

However to achieve that in practice we would need to build enough CO2 capture
plants to capture the CO2 released by all human activity, and we've been
building machines that release CO2 for decades. The effort to catch up is
immense. The similar company Climeworks, cited in the article, has an example
of such a plant here : [http://www.climeworks.com/our-
products/](http://www.climeworks.com/our-products/). The DAC-18 variant, which
looks like the prototype that they actually built, it is a complex 3 stories
high structure with 90m^2 of ground area, and according to the product page it
can capture 2460 kg per day, although that is probably under ideal conditions
and in practice it could be considerably less. According to a quick search we
released around 36.75 Gt of CO2 last year. To capture that, we would need to
build 36.75e12/365/2460 = 41 million such plants, at the bare minimum. And
that would be only break even, we'd need even more to start capturing the
excess CO2 already in the atmosphere. That seems unrealistic.

~~~
sjg007
Well, we could plant more trees, not deforest the Amazon.. Maybe grow some
algae or something too.

------
WalterBright
Probably the most cost-effective way of sucking CO2 out of the air is planting
trees on a huge scale.

~~~
cbHXBY1D
A user on reddit did some napkin math on the r/science submission of this
article. The tl;dr is we don't have enough land area for the amount of trees
needed to sequester 1,100 gt of carbon.

[https://www.reddit.com/r/science/comments/8pbuqv/sucking_car...](https://www.reddit.com/r/science/comments/8pbuqv/sucking_carbon_dioxide_from_air_is_cheaper_than/e0aendn/)

~~~
WalterBright
Trees can't do it all, but they can help a lot and are cheap and we like
trees!

------
carapace
Bubblers and tubes of algae in the sun. The bubbles stir the algae to maximize
growth. Add a few goldfish to help cycle nutrients[1]. You can get the algae
so thick that a test stick (plastic spoon) can't be seen beyond a centimeter
deep.[2]

At this stage you can remove _half_ of the algae each day and they'll
regenerate within twenty-four hours.[3] The extracted algae biomass (mostly
composed of atoms that used to be air or water) can be "upcycled" by feeding
to higher organisms (fish, earthworms, etc.) or processed industrially for
e.g. plastics, fuel, foodstuffs, whatever.

Ah, here we go, a few people are doing it already:
[http://www.iflscience.com/environment/urban-algae-farm-
gobbl...](http://www.iflscience.com/environment/urban-algae-farm-gobbles-
highway-air-pollution/)

The important thing is it's cheap as heck and doesn't require fancy
technology.

[1] Goldfish eat algae. Few in the tank makes it a simple aquaculture system.

[2] I looked for images of "tubes of algae in the sun" and most of them were
transparent. If you can see through the tube you're doing it wrong.

[3] If conditions are optimal, otherwise you might have to be happy with
35-40%.

~~~
maxbond
I'm bullish on algae but you may want to adjust your expectations. If you have
a photobioreactor, with algae growing too densely to see through, in the sun,
with goldfish, you're probably going to cook your goldfish.

You're talking about engineering an ecosystem, and it is fancy technology. pH,
temperature, and salinity all need to be copacetic. There's a reason
"everyone" does aquaponics with talapia and vascular plants. Aquaponic systems
usually run at pretty abysmal water qualities, but talapia will live in mud
and vascular plants don't mind having lots of nutrients in their water. Algae
will have a hard time growing at that high density you're imagining if they're
being shaded by murky brown water. Of course these systems will have pretty
big algae blooms, but usually these are biofilms growing attached to the walls
of the system, close to the surface.

If you feed the algae to other organisms, they're going to die and that carbon
is going to turn into methane, which is 23 times more powerful a greenhouse
gas than CO2.

There's also the matter of growing algae in tubes made of petroleum plastic.
How much carbon went into mining & processing the petroleum, manufacturing
your tubes, and transporting them out to where your facility is, 100 miles
from the nearest Starbucks? How long will it take you to pay off that carbon
debt? (If there's a biobased alternative I'd love to hear about it.)

But there are solutions as well as problems. Aquaponic systems don't have to
be directly coupled, for instance. And those biofilms are much denser than
planktonic growth (ie tubes). My main "research" area (calling me a researcher
would be too generous) is attached growth cultivation systems, for a lot of
these same reasons. Pyrolysis can be used to turn the carbon into a biochar
with very low bioavailability, solving the issue with methane.

PS

Just to clarify, bubbling doesn't maximize growth as much as keep the algae
alive. Keeping high-density algae well mixed does ensure that everyone gets
their turn to be in the sun. But algae can't survive in an anoxic environment,
and without aeration a tall column of water will quickly become anoxic. The
algae on the bottom will rot and you're back to converting CO2 into methane
(which, in most systems, would come right out of the top of the tube).
Additionally, aeration provides CO2; no CO2 would mean no photosynthesis.

~~~
carapace
Thanks for the detailed response!

I'm on the crackpot spectrum but I'll try not to waste your time. :-)

As I mentioned in a different sub-thread, I started looking at algae as part
of a system to reprocess oceanic plastic trash into biomass, so my particular
ideas and designs are probably not going to be directly applicable to CO2
sequestration.

> I'm bullish on algae but you may want to adjust your expectations. If you
> have a photobioreactor, with algae growing too densely to see through, in
> the sun, with goldfish, you're probably going to cook your goldfish.

In the context of an ocean-going plastic recycling system I hadn't thought of
heat pollution before because I assumed I would have the thermal mass of the
ocean in which to dissipate excess heat.

To handle it you could: reduce the infrared light reaching the tubes; chill
the incoming air with e.g. Ranque-Hilsch vortex tube [1]; put radiator fins on
the shade side; use heat-tolerant fish; hang evaporative coolers in between
the tubes; rotate the tube assemblies.

> You're talking about engineering an ecosystem, and it is fancy technology.
> pH, temperature, and salinity all need to be copacetic. There's a reason
> "everyone" does aquaponics with talapia and vascular plants. Aquaponic
> systems usually run at pretty abysmal water qualities, but talapia will live
> in mud and vascular plants don't mind having lots of nutrients in their
> water. Algae will have a hard time growing at that high density you're
> imagining if they're being shaded by murky brown water. Of course these
> systems will have pretty big algae blooms, but usually these are biofilms
> growing attached to the walls of the system, close to the surface.

I cheat: I went to a pond and scooped up water and some of the bottom muck.
Start with a viable ecosystem; in the tank it wobbles but then stabilizes; my
experimental system ran for months with no adjustments.

At scale, I'd adopt a kind of evolutionary attitude, any tube that went bad
would be flushed and replaced with a colony from a healthy tube. Combine that
with a simple automated feedback system to help keep tubes in the optimal
ranges and I think it would be pretty stable overall (depending on the failure
rate of the tubes.)

If you have one seawater tank in your living room you're gonna have to paper
and baby that thing. If you have thousands of simple robust ecosystems in
tubes and some go bad you can just flush 'em. (And if you're worried about
contaminates, chemical or biological, you can flush them through the MSO
reactor. Those things are used to dispose of ordinance and chemical weapons.
They really _really_ break down molecules. _Mad cow prions_ wouldn't make it
through. Heck, you could toss the tube in there.)

Biofilms are fascinating! FWIW, in the experiment I ran the fish kept the
inner surfaces of the tube pretty clear, I didn't have to do any scrubbing.

> If you feed the algae to other organisms, they're going to die and that
> carbon is going to turn into methane, which is 23 times more powerful a
> greenhouse gas than CO2.

I want to experiment with feeding the algae to compost worms. These prefer
just-slightly-decayed plant matter so I am thinking they would gobble up the
algae as it died. Basically, you'd drain half the water in a tube directly
into one end of a worm bed. The bed filters the algae out of water which also
picks up nutrients. Some of the outflow would be put back into the tubes
directly; the rest would be distilled to make a high grade fertilizer and the
excess water condensed and returned to the tubes.

(The worms also eat their own dead. Gruesome, but it speaks to your point
about turning into methane.)

> There's also the matter of growing algae in tubes made of petroleum plastic.
> How much carbon went into mining & processing the petroleum, manufacturing
> your tubes, and transporting them out to where your facility is, 100 miles
> from the nearest Starbucks? How long will it take you to pay off that carbon
> debt? (If there's a biobased alternative I'd love to hear about it.)

Well, bioplastic.[2] I'm also looking at drying out the algae in sheets and
using [some kind of] glue to bond them into a membrane, as opposed to going
through a chemical process to convert them into plastic. Once you've got
sheets and glue you can build your structures out of inflatables. [3]

> But there are solutions as well as problems. Aquaponic systems don't have to
> be directly coupled, for instance. And those biofilms are much denser than
> planktonic growth (ie tubes). My main "research" area (calling me a
> researcher would be too generous) is attached growth cultivation systems,
> for a lot of these same reasons. Pyrolysis can be used to turn the carbon
> into a biochar with very low bioavailability, solving the issue with
> methane.

I hadn't heard of "attached growth cultivation systems" specifically but they
make a lot of sense. Just skimming the wikipedia article I think I can see a
lot of low-hanging fruit in terms of efficiency gains.

Are you aware of the "Living Machine" stuff?

> Living Machine is a trademark and brand name for a patented form of
> ecological sewage treatment designed to mimic the cleansing functions of
> wetlands. ... the latest generation of the technology is based on fixed-film
> ecology and the ecological processes of a natural tidal wetland, one of
> nature’s most productive ecosystems.

~
[https://en.wikipedia.org/wiki/Living_machine](https://en.wikipedia.org/wiki/Living_machine)

To me biochar seems like a very exciting path for CO2 sequestration. Not so
much on the ocean for obvious reasons, but if I had any land at all I would be
trying it out.

> Just to clarify, bubbling doesn't maximize growth as much as keep the algae
> alive. Keeping high-density algae well mixed does ensure that everyone gets
> their turn to be in the sun.

Yeah, you explained it better than I did. Cheers. :-)

> But algae can't survive in an anoxic environment, and without aeration a
> tall column of water will quickly become anoxic. The algae on the bottom
> will rot and you're back to converting CO2 into methane (which, in most
> systems, would come right out of the top of the tube). Additionally,
> aeration provides CO2; no CO2 would mean no photosynthesis.

Well again, my ideas are developing in the context of a system that would have
lots of CO2 already bubbling through a water column anyway. [4] If the bubbles
are failing I've got bigger problems.

[1]
[https://en.wikipedia.org/wiki/Vortex_tube](https://en.wikipedia.org/wiki/Vortex_tube)
solid state; separates a presurized flow of air nito hot and cold portions. I
suspect it has applications in separating gas mixtures.

[2]
[https://en.wikipedia.org/wiki/Bioplastic](https://en.wikipedia.org/wiki/Bioplastic)

[3]
[https://en.wikipedia.org/wiki/Tensairity](https://en.wikipedia.org/wiki/Tensairity)

[4]
[https://en.wikipedia.org/wiki/Molten_salt_oxidation](https://en.wikipedia.org/wiki/Molten_salt_oxidation)
MSO converts plastic to a mixture of H2 and CO; run that through a water
column and you get CO + H2O -> CO2 + H2; so now you have a bunch of hydrogen
and carbon dioxide. Run that through a vortex tube to separate the gasses,
send the H2 to fuel cells and the CO2 to the algae tubes... Where there used
to be oceanic plastic trash there is now power and biomass.

~~~
maxbond
Thank you for your detailed response as well, it's always heartening to see
people chipping at these problems. FWIW I've met plenty of crackpots and you
are not one of them. You become a crackpot when you can't tell the difference
between what is true and what you want to be true, not when your ideas are
"out there".

Regarding your experiment with the fish, I suspect this is a difference in
your environment, as you alluded to. I'm out here in the desert, and it is
sunny and it is hot, and if you're maintaining a low evaporation rate there's
no where for that heat to go. Algae don't usually mind though. If you deploy a
tube out here it'll only be so long until it gets warped and won't accept a
pig (basically a plug that moves along a pipeline & cleans the sides), so I'm
very interested in this idea of having the fish clean the tube. But I suspect
that the same technique would go belly-up for me, pun fully intended.

I completely agree with your evolutionary approach and with using ecosystems
that are already functioning. I did the desert equivalent and found my
attached growth culture under a rock.

I was not aware of Living Machine but thanks for pointing it out. I think a
lot about a similar concept called Algae Turf Scrubbers
([http://algalturfscrubber.com/](http://algalturfscrubber.com/)) (also
trademarked), which mimic coral reefs.

You clearly have put a lot of thought into this so I hope I'm not rehashing
ideas you've already dismissed, but here it goes.

You may want to consider using fungi. They are the matchless experts in
breaking down toxic material, and my inkling is that they will be the ones to
crack the problem of digesting plastics. Some organisms have started to do
this already. Fungi have the ability to learn and adapt as individuals, so
they're more friendly to this sort of engineering than most complex lifeforms.
Microalgae are of course fantastic because they evolve on human timescales.

Keep in mind that plastics aren't really pure hydrocarbons. It would be very
nice if they were. But they'll come with paints and stabilizers and such, and
you'll end up with heavy metals and other contamination (I won't pretend to
understand the intricacies here). If this ends up in your biomass then it
cannot be used for agriculture. Dirty biomass is usually fine for fuel
production, however. I'm sure you've thought of this though and that I would
see your reasoning if I understood MSO reactors better. What happens to this
waste when it leaves your reactor is another big question.

Gas separation is hard. You might consider separating the nitrogen and calling
that good. The more conventional approach would be to use a pressure swing
absorber but I'm taking the impression you want to use your vortex tube for
cooling as well as separation. I've never tried pumping pure CO2 through an
algae culture, but I believe it will become toxic at some concentration.

Rather than feeding it to worms, you might consider an anaerobic digester.
You'll still produce fertilizer but you'll also be able to capture methane,
which you can blend with your H2 and send to a generator instead of a fuel
cell. While they have the same problems with shading as aquaponic systems, AD
effluents are a very good fertilization ratio for algae. (I'm remembering a
lecture here so I don't have a source to cite & don't recall the ratio, I'm
afraid.) Another advantage is that they can accept wet biomass, and harvesting
is often the most expensive part of the process. The methane could be blended
with hydrogen and fed into an off-the-shelf natural gas generator. But I
imagine that you did choose fuel cells for a reason. My personal view is that
developing technologies are expensive in terms of liability, and that you can
only pick a few of them. So if I were you I wouldn't put fuel cells and a
novel approach to gas separation in the same design. Of course methane can be
converted to hydrogen through steam reformation, or it can also be used in a
fuel cell. Maybe you can even put them in the same fuel cell, I don't
understand this technology whatsoever.

I've also got some more open ended questions you might find interesting to
think about.

Are you planning to do this on a barge or derrick? How will your process
effect the chemistry of the ocean around you? How will that effect the marine
life around you?

If you're concentrating metal contamination and taking water in from the
ocean, can you recovery dissolved metals? Perhaps you can combine this with
desalination?

Is there a way your project can help with ocean acidification?

This talk seems to paper over a lot of problems with this system (its one of
those "CO2 to methane" systems), as a TED talk does, but it's an interesting
idea & related to your problem space.

[https://www.youtube.com/watch?v=X-HE4Hfa-
OY](https://www.youtube.com/watch?v=X-HE4Hfa-OY)

You're probably aware but some people are producing hydrogen from algae. Could
enhance your yield.

[https://en.wikipedia.org/wiki/Biological_hydrogen_production](https://en.wikipedia.org/wiki/Biological_hydrogen_production)

------
sremani
This is good news, esp. given the context from this spectrum article why we
need some technologies like these..

[https://spectrum.ieee.org/energy/renewables/what-it-would-
re...](https://spectrum.ieee.org/energy/renewables/what-it-would-really-take-
to-reverse-climate-change)

------
exabrial
I'm curious how this competes with a bunch of algae in a lake

------
Reason077
It seems like at $94/ton CO2, we're still a long way from where this becomes
viable.

At that price, to offset humanity's annual 36 Gt CO2 emissions (36 _billion_
tons) we'd need to spend about $3.2 trillion. Per year.

Surely the cost of _reducing_ CO2 emissions - the cost of upgrading emissions
sources to alternative, lower-carbon technologies - is much less than $94/ton.
And that's where we should be focusing our efforts and funding for the
foreseeable future.

------
blacksqr
They say they can make synthetic fuel at $1/liter with CO2 input at $100/ton.
There's plenty of CO2 available commercially at about $20/ton. If they can
make synthetic fuel economically out of CO2, they should be doing that RIGHT
NOW, not waiting until they've perfected the air extraction process.

They could use the money they made from the fuel to speed up R&D on the
extraction process.

------
gustaf
Y Combinator is actively looking for companies working on this. If you are
working on this yoiu should consider applying.

[https://www.ycombinator.com/rfs/#carbon](https://www.ycombinator.com/rfs/#carbon)

[https://www.greentechmedia.com/articles/read/y-combinator-
is...](https://www.greentechmedia.com/articles/read/y-combinator-is-looking-
for-carbon-removal-startups#gs.2Xq_2VI)

I'm the YC partner who wrote the RFS and have been pushing this. I also went
to the first conference of Negative Emissions in world (I think) in
Gothenburg, Sweden last month.

It's clear that much of what is needed for this to work is coming together 1)
Research on underground storage is in a great place 2) Climeworks and Carbon
engineering + Klaus Lackner are the pioneering companies/researchers working
on Direct-Air-capture and they've shown the technology works. 3) California
recently/are currently implementing legislation that will allow companies up
to $180 per ton carbon removed and sequestered. This should be more than
enough to build a business doing this at scale. 4) Perhaps the most important
timing question is the fast drop in energy costs driven by solar. Energy is
the number once scaling cost-factor if you want to scale this up to have a
material impact on the climate. Solar is the obvious choice here since there
is barely any scaling costs once installed. California incentives also allows
you place your installations anywhere in the world. Mojave desert would be a
good place.

What is needed right now is you guys. We need entrepreneurs and founders who
want to start companies building both Direct-Air-Capture technology and
sequestration technologies. I've met many investors over the last 6 months are
looking actively to invest in these projects.

If you are working on these technologies you can email me
gustaf@ycombinator.com

Two other great resources here are

[http://www.centerforcarbonremoval.org](http://www.centerforcarbonremoval.org)

[http://www.airminers.org](http://www.airminers.org)

I'm convinced that whoever will build the most cost-effective way to remove
carbon from the air will both have a shot at a $100B+ market while saving the
earth at the same time. What could be more motivating?

~~~
carapace
Do you have any interest in algae-based solutions? (Cf. my comment in this
thread I just left:
[https://news.ycombinator.com/item?id=17268103](https://news.ycombinator.com/item?id=17268103)
)

I've done some crude experiments and "back-of-the-envelope" calculations and I
think there's "something there". FWIW)

~~~
gustaf
We have interest in anything where cost-efficient carbon removal is the goal.

We're not picking technologies at this point since no-one really knows.
Personally, I'm more excited about Direct-air-capture than I am about bio-
energy with carbon capture for a bunch of reasons. Storing carbon in oceans is
also interesting. Whatever path we see as a truly scalable way (like, can you
10000x your prototype and get costs benefits for example)

~~~
carapace
Okay, cool. If I come up with anything I'll drop you a line.

I started looking at algae as a way to convert oceanic plastic garbage to
something organic.

You can use Molten Salt Oxidation [1] to convert plastic to "synthesis gas"
[2] then feed that through a water column to convert CO+H2O to CO2+H2, then
recover the hydrogen for power and feed the carbon dioxide to algae tanks.

I was going to try feeding the algae to e.g. _eisenia foetida_ compost worms
[3] to make soil and then grow whatever in that. The basic idea was to turn
oceanic plastic into biomass.

But then I learned that you can make plastic out of algae. In order to be able
to scale the system (without capital) it should be designed to produce as much
of its own structure (like a "reprap" self-replicating machine) as possible.
The limiting factors should be CPUs and magnets (for motors.)

But this is predicated on being isolated in the middle of the ocean and not
having access to capital. I can't evaluate the optimal way of using this stuff
in the context of being close to the rest of the economy and with capital, as
there are too many variables and I'm kind of ignorant and stupid. (In other
words, in a hypothetical universe where someone gave me a big pile of money to
try this, the first thing I would do is recuse myself in favor of someone who
actually knew what they were doing.)

[1] An exothermic reaction
[https://en.wikipedia.org/wiki/Molten_salt_oxidation](https://en.wikipedia.org/wiki/Molten_salt_oxidation)

[2] "fuel gas mixture consisting primarily of hydrogen, carbon monoxide, and
very often some carbon dioxide"
[https://en.wikipedia.org/wiki/Synthesis_gas](https://en.wikipedia.org/wiki/Synthesis_gas)

[3]
[https://en.wikipedia.org/wiki/Eisenia_fetida](https://en.wikipedia.org/wiki/Eisenia_fetida)

~~~
maxbond
It's called synthesis gas for a reason, if you have syngas, catalysts, and
fricktons of energy you can do a lot of things, including making precursors
for plastics through Fischer-Tropsch synthesis.

------
rdiddly
What's that old saying... usually misattributed to Einstein... you can't solve
a problem using the same frame of mind that created it? We have a problem of
too much CO2 caused by massive deployment of complex, energy-intensive
industrial facilities and processes, and they want to fix it using a fairly
complex and energy-intensive industrial facility/process (with giant air
blowers and all), that itself is dependent on other complex industrial
processes for its manufacture, transport, construction and operation. And
perpetual energy use to run the fans... I mean? Are we sure it's a net
positive CO2 capture after all that? And if so, is it still a net positive
after the CO2 they've captured is turned (by means of even more energy input)
into "low carbon fuels" that are then burned, releasing CO2 back into the
atmosphere?

I mean it's great if it works and all. I just feel like the real solution
doesn't look like this.

------
DrTung
In a few years I'll probably have grandkids and when I read this, think it
increases the chance that those kids will still be able to go to Disney World
in Florida, i.e. it will not be submerged.

~~~
mikec3010
By that time Disney world will just be a VR app you load on your 8k
VirtualStation via fiber optic link with others. Disney will long have
replaced all their parks with simulation because focus groups found that while
consumers preferred the real park, the amount of lost park sales was less than
the gains of zero liability, shutting down the park and firing those employees
who were eating into shareholder profits. The park now only exists as a museum
and luxury apartment homes, with paid autonomous bus tours.

------
Jupe
"Climeworks has also opened a second facility in Iceland that can capture 50
tonnes of CO2 a year and bury it in underground basalt formations. "

Taking Oxygen from our atmosphere (the gas we need to breathe) and pump it
underground after we've combined it with Carbon seems like an atrociously bad
idea.

Taking CO2 out is only half the battle. We're going to need that oxygen.
Pumping it into greenhouses seems better, but not very cost effective: You
need to build these machines, then build the greenhouses, then transport
tonnes of CO2 to the greenhouses... Seems much more cost effective to build
windmills, solar arrays and the like!

~~~
Symmetry
Earth's atmosphere is 20.946% O2 and .047% CO2. The amount of oxygen tied up
in CO2 these days is really tiny.

------
Robotbeat
Good. Then we should immediately require fossil fuel companies to do this or
pay for someone else to do it as well as long-term storage and insurance for
the storage.

------
tamaharbor
This machine does the work of six people. Unfortunately, it takes ten people
to operate it.

------
erikig
Yep, just plant a tree or two ;)

------
cvaidya1986
What if we all plant 2 trees each in our lifetime?

------
btomtom5
Are these machines cheaper than trees?

------
mncolinlee
Wouldn't it be likely that the greater than percentage of free CO2, the
cheaper removing CO2 will get per ton? Trump's intransigence could make this
technology viable.

------
jillesvangurp
Here's a related article that circulated in finnish media a few days ago:
[https://yle.fi/uutiset/osasto/news/finnish_researchers_use_a...](https://yle.fi/uutiset/osasto/news/finnish_researchers_use_air_solar_power_to_create_renewable_hydrocarbon/9661164)

This is about the apparent work of a Finnish researcher to come up with a
scalable way to produce fuel from air such that it can be done locally. Think
gas stations producing their own gas. Right now this would be relatively
expensive because of energy cost but as those drop and the technology is
improved, that cost can go down.

Stuff like this not surprising for anyone that has followed news around
renewables lately and a very cool side effect of the fact that renewable
energy prices have been dropping exponentially for quite some time now
combined with the fact that the cost of lots interesting chemical processes
are primarily driven by how much energy is required. As energy becomes
cheaper, those chemical processes become more feasible and the demand for more
energy causes people to invest in making that cheaper further. The same
economic dynamic that is causing us to destroy our planet is also producing
the solutions for saving it.

For example, producing clean water is a trivial process if you have cheap
energy. This is why desalination plants are popping up in lots of places where
clean water is scarce and they tend to be paired with wind/solar plants. You
can also produce fuels out of water and the resulting fuels, whether it is
hydrogen or hydrogen peroxide, are useful ways of storing energy.

Oil is a scarce resource that is hard to procure and therefore relatively
expensive. If there's an energy intensive way to produce oil from CO2, that's
great news because that means it's just a matter of time before the price of
that energy drops enough to make that worthwhile.

Things like this can go from being too expensive to only slightly more
expensive to being magnitudes cheaper in the near future.

What I love about this is that climate change can be countered with simple
economics rather than idealism. Once we stop pumping new co2 in the atmosphere
for cost reasons because we found a more cost effective way to just suck it
from the atmosphere, nature will do it's thing and help us revert the effects
of the past centuries. We don't actually need to actively clean up the
atmosphere, our planet is fully capable of doing that by itself given enough
time.

Also worth pointing out that oil is used for more than just fuel. So, stuff
like this is relevant even if we switch to electric vehicles. We still need to
produce plastics and other materials. All of that can in principle be done
with co2 harvested straight from the air as well.

------
jlebrech
It would be cool to have a country which used the rest of the world's
pollution to create it's own energy.

------
FrozenVoid
Its not profitable to clean: even if cleaning was paid for by the government,
most cleaning efforts would be commercial enterprises simulating maximum
cleaning effort(like the incentive to collect rat tails will result in rat
breeding farms, the "environment cleaning industry" will be most profitable
with more pollution and costlier cleaning incentives/bonuses ).

It will result in encouraging more pollution and removing all safeguards(clean
coal? we'll clean it up later!) towards a new industry whose main interest
would be preserving pollution forever to profit from cleaning it up.

Like a pharmaceutical industry, the symptoms are more profitable than curing
the disease completely.

------
User23
I worry that well-meaning efforts at mass climate engineering will cause far
more harm than letting nature run her course.

I'm not convinced there is a causal relationship between human activity and
CO2 levels or average temperatures (ignoring urban heat island and similar
effects). Sure there is a correlation, but we all know what that means. The
kind of atmospheric engineering that scares me is exactly the tool that would
be required to show a causal relationship.

Another point of concern is that none of the doom and gloom predictions are
made by any climate model. All a climate model can do is make predictions
about, well, climate. It takes an economic or some other sociological model to
predict how that change in climate will affect human beings and societies, and
what the costs (and benefits!) will be. Even if you trust the climate models
100% you'd be a fool to trust the economic or sociological models. How can one
rationally justify an intervention is worth the cost when one can't know the
cost of what is being prevented?

~~~
Faaak
You should take a look at: [https://xkcd.com/1732/](https://xkcd.com/1732/)

If you still think that humans are not the cause, well…

~~~
thefurman
Using a comic strip as an argument, well...

~~~
JeffreyKaine
XKCD has a long history of citing their work, why can't an effective argument
be made with visuals? I don't understand why the medium of the argument
matters here.

~~~
thefurman
There is no argument made, it's a comic strip.

~~~
JeffreyKaine
There is definitely an argument made. It might not be in the form that you're
looking for, but the argument is there. The graph clearly points to a high
correlation between the industrial revolution and a fast and huge (relative to
other changes) rise in temperatures. How is this not an argument?

~~~
thefurman
Yes, very clearly, sure. You don't even know the very basics of scientific
methodology, statistics, interpreting data, or critical thinking.

