
Stripping CO2 from the air and using it to produce carbon-neutral fuel - fold_left
https://www.theguardian.com/environment/2018/feb/04/carbon-emissions-negative-emissions-technologies-capture-storage-bill-gates?CMP=Share_AndroidApp_Copy_to_clipboard
======
plaidfuji
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.

~~~
seszett
> _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.

~~~
jjoonathan
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

~~~
brians
Could you expand on net energy gain?

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

~~~
jjoonathan
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.

------
exabrial
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.

~~~
graeme
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.

~~~
hedora
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.

~~~
graeme
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.

~~~
skosch
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/](https://citizensclimatelobby.org/)

------
pfooti
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).

~~~
88e282102ae2e5b
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.

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

------
foxhop
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...](https://halfhillfarm.com/2017/04/21/how-hugelkultur-can-help-heal-
the-planet/)

~~~
nanomonkey
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.

~~~
foxhop
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.

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

------
acabal
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?

~~~
intopieces
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.

~~~
kardos
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](https://en.wikipedia.org/wiki/Wind-assisted_propulsion)

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

------
Santosh83
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.

------
ilyagr
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.

~~~
ams6110
If the energy is "free" (wind or solar) the efficiency matters a lot less.

------
tscs37
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]

~~~
philipkglass
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.

------
avmich
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?

------
dredmorbius
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...](https://www.reddit.com/r/dredmorbius/comments/28nqoz/electrical_fuel_synthesis_from_seawater_older/)

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...](https://www.reddit.com/r/dredmorbius/comments/2cvap7/the_intractable_problem_of_biomass_for_fuels_is/)

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](http://www.hubbertpeak.com/hubbert/EnergyResources.pdf)

Steinberg's obituary, from 2015: [https://www.newsday.com/long-island/meyer-
steinberg-of-melvi...](https://www.newsday.com/long-island/meyer-steinberg-of-
melville-worked-on-manhattan-project-1.10603175)

------
detritus
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.

------
technicalbard
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...

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

~~~
phkahler
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.

~~~
dllthomas
> 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.

~~~
phkahler
>> 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...

~~~
dllthomas
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.

~~~
phkahler
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.

~~~
hedora
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.

------
rini17
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.

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

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

------
lazyjones
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.

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

~~~
lazyjones
> _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.

~~~
eloff
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.)

~~~
hedora
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?

------
blacksqr
What is "burning wood" Alex?

~~~
fold_left
You might want to see your Doctor

------
briantakita
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.

