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Latest Climate Change Solution: Direct Air Capture Powered by Geothermal Energy

Guest essay by Eric Worrall

Why bother with capturing concentrated CO2 from combustion exhaust, when you can spend “a wartime level of funding” capturing trace concentrations of CO2 directly out of the air?

Engineers have built machines to scrub CO₂ from the air. But will it halt climate change?

January 21, 2021 6.08am AEDT

Deanna D’Alessandro
Professor & ARC Future Fellow, University of Sydney

US research published last week suggested global warming could be slowed with an emergency deployment of a fleet of “CO₂ scrubbers” using DAC technology. However a wartime level of funding from government and business would be needed. So is direct air capture worth the time and money?

What’s DAC all about?

Direct air capture refers to any mechanical system capturing CO₂ from the atmosphere. Plants operating today use a liquid solvent or solid sorbent to separate CO₂ from other gases.

Swiss company Climeworks operates 15 direct air capture machines across Europe, comprising the world’s first commercial DAC system. The operation is powered by renewable geothermal energy or energy produced by burning waste.

Canadian company Carbon Engineering uses giant fans to pull air into a tower-like structure. The air passes over a potassium hydroxide solution which chemically binds to the CO₂ molecules, and removes them from the air. The CO₂ is then concentrated, purified and compressed.

DAC technology is currently expensive, relative to many alternative ways of capturing CO₂, but is expected to become cheaper as the technology scales up. The economic feasibility will be helped by the recent emergence of new carbon markets where negative emissions can be traded.

DAC machines process an enormous volume of air, and as such are very energy-intensive. In fact, research has suggested direct air capture machines could use a quarter of global energy in 2100. However new DAC methods being developed could cut the technology’s energy use.

Read more: https://theconversation.com/engineers-have-built-machines-to-scrub-co-from-the-air-but-will-it-halt-climate-change-152975

Potassium hydroxide, a potent form of hardware store lye, is pretty good at grabbing CO2 out of the air. The difficult part is getting the potassium to let go of the CO2 it just grabbed, and regenerating the lye.

The “new DAC methods” use organic metal compounds, kind of like how your body uses metal organic haemoglobin in your blood to transport oxygen. Incorporating metal into an organic compound in principle lets you engineer the metal’s CO2 grabbing tendencies to better match requirements. But organic metal compounds tend to be fragile, easily damaged by contaminants or regular wear and tear – your body devotes a lot of resources to replacing damaged haemoglobin. So it will be interesting to see how this new organic metal compound process handles real world conditions.

Regardless of the exact process selected I doubt this approach to reducing CO2 will make a significant difference to atmospheric CO2 in the foreseeable future. The idea of grabbing CO2 directly from the air just seems absurd when there are far more efficient alternatives available. If you want to spend taxpayer’s money setting up a CO2 mine, surely it would make more sense to grab your CO2 from a concentrated source like a big industrial smokestack, or grow a few more trees, rather than setting up an industrial process to try to filter trace amounts of CO2 from the atmosphere.

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mikebartnz
January 21, 2021 10:13 pm

This is not new but is still more insanity. What happens when they suck the Co2 levels below 150ppm?

Pauleta
Reply to  mikebartnz
January 21, 2021 10:22 pm

Plants die, and so do we and other animals. I hope someone leaves a note to document the end so whenever some fish comes out of the water, after some million years someone will know.

Joel O'Bryan
Reply to  mikebartnz
January 21, 2021 10:34 pm

Why CO2 is not pollution. Despite what the idiots like John Kerry say.
Real pollution can be reduced 10X (90%), or a 100X (99%), and be beneficial.
But reduce atmospheric levels of CO2 by 10X (to 40 ppm) and we all die. CO2 is the essential gas of all life on this planet. Atmospheric CO2 is the origin of the carbon in every organic molecule in our bodies.
And many of the carbon atoms in our bodies today are from oil, gas, and coal hydrocarbons long stored in oil for millions of years, burned in the last 150 years.
There is no difference between a CO2 molecule from ‘nature’ and a CO2 molecule from fossil fuel burning.

Last edited 4 months ago by joelobryan
Scissor
Reply to  Joel O'Bryan
January 22, 2021 5:59 am

Excellent point. Actual pollutant reduction results in some measurable benefit.

menace
Reply to  mikebartnz
January 22, 2021 7:59 am

They will turn them off at 220 ppm and declare mission accomplished? Climate Perfection!

But then 40 years later they’ll realize the scientists from the 70’s were right and an “ice age” is indeed coming just around the corner and then they say “burn baby burn” again to fossil fuels to try to stem off the ice age. Or pop the corks off the underground CO2 stores or whatever.

Reply to  mikebartnz
January 22, 2021 8:03 am

“What happens when they suck the Co2 levels below 150ppm?”

The existential threat they seem so concerned about will arrive. It’s a classic example of a self fulfilling prophesy.

TonyG
Reply to  mikebartnz
January 22, 2021 8:58 am

I was just about to ask the same question. It appears their “target” is 180ppm, 150 wouldn’t be too much of an overshoot.

Talk about “existential threats”

Robert of Ottawa
Reply to  mikebartnz
January 22, 2021 12:41 pm

Given that CO2 is essential and beneficial to life, I wouldn’t call it an insane scheme, I would call it a criminally insane scheme.

Last edited 4 months ago by Robert of Ottawa
Richard G.
Reply to  mikebartnz
January 22, 2021 1:11 pm

Indeed,this is not new.
Plants operating today use a liquid solvent or solid sorbent to separate CO₂ from other gases.”
Excuse me silly, but plants have been using chloroplasts to capture CO2 since time immemorial. Let’s go to a wartime footing to reinvent the wheel here to capture other people’s money.

January 21, 2021 10:22 pm

Below 150 ppm. CO2 the vegetation starts to die off and you will not even be able to eat the grass as directed. They are truly insane.

Tom Abbott
Reply to  nicholas tesdorf
January 22, 2021 4:01 am

“They are truly insane.”

Especially when you consider there is no evidence that CO2 is doing anything the Alarmists claim it is doing. CO2 is a benign gas that is essential for life on Earth, and ignorant humans should stop messing with it.

Paul Johnson
January 21, 2021 10:25 pm

It would seem much cheaper and easier to use Direct Air Capture powered by solar energy, e.g. trees.

Pauleta
Reply to  Paul Johnson
January 21, 2021 10:34 pm

I don’t think these people understand photosynthesis.

Reply to  Pauleta
January 22, 2021 8:04 am

I don’t think they understand science at all.

Joseph Zorzin
Reply to  Paul Johnson
January 22, 2021 6:01 am

Exactly. As a forester since Nixon was in the White House- I know that with improved forestry we can not only sequester more carbon but also produce more and better wood products- not that I accept the alarmist faith in climate threat because I detest that new religeon. Here in Massachusetts- we have a new “decarbonization by 2050 law”. A recent webinar by the state’s “climate czar”, David Ismay- said that we can easily end about 85% of fossil fuel use by 2050 and that we’ll have to find ways to sequester the rest to be net zero- with much of this to be done by forests. I asked what he meant by that but he didn’t explain. I suspect they’ll try to lock up the forests and thus wipe out the small timber industry. The state already imports most wood products so we’ll have to import the rest. What this decarbonization bill fails to account for is the carbon emissions of the products we import and we now import almost everything- since little is produced in Mass. now, having exported most factories to China and Mexico. About the only surviving industries are hospitals, colleges and bureaucracies- with the state bureaucracy being the largest employer in the state.

Peter W
Reply to  Joseph Zorzin
January 22, 2021 9:42 am

But all of that tree growth causes more shade, and everybody knows it is colder in the shade. We will be bringing about the next ice age!

Lrp
Reply to  Joseph Zorzin
January 22, 2021 10:23 am

They are costs and misguidedly called industries.

Joel O'Bryan
January 21, 2021 10:27 pm

Why harvest CO2 when it is more profitable to harvest OPM in the name of CO2?

Last edited 4 months ago by joelobryan
Joel O'Bryan
Reply to  Joel O'Bryan
January 21, 2021 11:41 pm

I mean … Really!!
Most of the Toads behind these CCS schemes are MBA’s, toads without a freaking clue as to the science or engineering behind what they propose.

They have absolutely no concept of how hard it is (energetically) to harvest air+CO2 at 400-500 ppm CO2 into cryogenic liquid CO2. At least with a coal or nat gas exhaust plume you’re starting with ~40,000 ppm or more of CO2 to make it worthwhile from an extraction standpoint.

They are completely depending on getting some Green weenie politicians to provide OPM (aka, tax payer money) subsidies to these schemes to make them profitable for investors (second) and themselves (first).
Harvesting OPM is what they really are pitching.

Last edited 4 months ago by joelobryan
Willem69
Reply to  Joel O'Bryan
January 22, 2021 3:53 am

It’s simple really, once fossil fuels are banned there is no more exhaust to capture CO2 from. Which would be the end of your CCS business. A more sustainable approach is needed so why not capture CO2 from the air directly and have a never ending money making concept?
Business problem solved!

It’s just to bad it doesn’t actually do anything useful, but is great for the shareholders.

best,
willem

Phillip Bratby
January 21, 2021 10:55 pm

“Plants operating today use a liquid solvent or solid sorbent to separate CO₂ from other gases.” And there was me thing it was chlorophyll.

Joel O'Bryan
Reply to  Phillip Bratby
January 21, 2021 11:29 pm

Technical note:
The Calvin-Benson cycle (i.e. Calvin cycle, the dark reactions) harvests CO2 using the stored energy in a molecule called “NADPH” (the electron carrier) to reduce CO2 to the organic sugar forms of carbon.
It is the light reactions of chlorophyll (photosystems II and I) that harvests short-wave (green-red) photons to split H2O to make oxygen and NADPH.

A more correct term to use would be “photosynthesis”, as that term captures the entire biochemical process that the light harvesting chlorophyll is just a part of. The carbon reduction to sugar is really separate from chlorophyll.

Last edited 4 months ago by joelobryan
Alexy Scherbakoff
January 21, 2021 11:00 pm

I don’t understand why they are doing it that way.
You take limestone and burn it in a kiln and produce calcium hydroxide, Then you combine the CO2 emitted from this process and form calcium carbonate. The result is that you use a lot of electricity/ fossil fuels to achieve this for no net result.
You make your profit from subsidies and selling carbon credits.

fred250
Reply to  Alexy Scherbakoff
January 22, 2021 12:03 am

I don’t understand why they are doing it that way.

——–

——–

You make your profit from subsidies and selling carbon credits.

.

I thought you said you didn’t understand 😉

Scissor
Reply to  Alexy Scherbakoff
January 22, 2021 6:01 am

And potassium hydroxide is mainly made via electrolysis.

Rafe Champion
January 21, 2021 11:10 pm

They have got to be joking!

DAC technology is currently expensive, relative to many alternative ways of capturing CO₂, but is expected to become cheaper as the technology scales up. The economic feasibility will be helped by the recent emergence of new carbon markets where negative emissions can be traded.

DAC machines process an enormous volume of air, and as such are very energy-intensive. In fact, research has suggested direct air capture machines could use a quarter of global energy in 2100. However new DAC methods being developed could cut the technology’s energy use.

Where do they think that quarter of global energy is going to come from? It will have to compete with the burgeoning green hydrogen industry that supports the green steel industry etc etc. Not to mention the vast number of electric vehicles. This looks like an experiment to see how far you can go before even the most ardent RE enthusiasts realise they are being ridiculed.

Clyde Spencer
Reply to  Rafe Champion
January 22, 2021 9:19 am

There was a time when technologists like Edison, Steinmetz, Westinghouse, Carnegie, Ford, etc. brought us inventions that provided job opportunities, automated most manual labor, and left us with more disposable income that we could spend as we wanted, ultimately improving our standard of living. The market decided what inventions would be embraced. Now, politicians, economists, and zealots, who know nothing about science or technology and are impressed with how smart they think they are, are trying to dictate what people can use and how much they will pay for it. This will not end well.

gringojay
January 21, 2021 11:16 pm

The ironic feature of these kinds of installations is that moving out the captured CO2 is considered most feasible through long pipe lines. While in the USA president Biden* (he is contemporaneously being denoted with an asterisk) deems pipe lines so nefarious an executive order was immediately issued stopping permits for the Keystone XL pipeline. It remains to be seen whether some carbon is better than other carbon & if oil of color is subject to disparate impact than gas of no color.

gringojay
Reply to  Clyde Spencer
January 22, 2021 11:01 am

Quite appropriate link points out that the existing PetraNova (Texan) carbon capture operation has been “… offline since oil prices plummeted.” Which reveals how the practicality of those kinds of strategies requires oil prices to go up; which in turn underscores how USA president Biden* is enacting policies that will definitely cause oil prices to rise for the nation.

observa
January 21, 2021 11:40 pm

Just burn lots of wood and then you can have gas power cheap and reliable-
Legal bid to stop UK building Europe’s biggest gas power plant fails (msn.com)
Get sleepy Joe onto this Green New Deal right away.

observa
Reply to  observa
January 22, 2021 12:15 am

Look in the interest of kumbayah coming together and keeping Loydo and Co happy changing the climate I think we skeptics can all manage a wood fired barbecues and pizza ovens out the back for the reliable gas powered aircons inside.

Scissor
Reply to  observa
January 22, 2021 6:05 am

Coal fired pizza is the best.

ColMosby
January 22, 2021 2:43 am

The ignorance of those worried about CO2 is breathtaking. For less than one trillion dollars, the U.S. can build enough small modular molten salt nuclear reactors which, when combined with existing conventional nuclear reactors and hydro, can result in carbon free power generation.

Beta Blocker
Reply to  ColMosby
January 22, 2021 10:00 am

According to this Forbes article by Dr. James Conca, roughly 37,000 megawatts of America’s nuclear capacity will have been prematurely retired by the end of 2026. That’s roughly one-third of the nuclear power capacity we had in 2010.

Premature Nuclear Reactor Retirements Could Affect Nuclear Waste Disposal

Since 2012, twelve commercial reactors have shut down in the United States totaling about 10,348 MW of capacity (Table 1), losing over a trillion kWhs from their expected life assuming one license extension for half of them and two license extensions for the other half.

An additional twenty-seven reactors have announced closures by 2025 totaling about 27,203 MW of capacity (Table 2), or about 4 trillion kWhs from their previously expected life. Although all are expected to close before 2026, closure dates have not been set for some reactors.

That we are retiring existing nuclear capacity in favor of greatly more expensive alternatives — some of which include building new-technology nuclear plants at a cost which is triple or even quadruple what it cost in current dollars to build the ones we are prematurely retiring — this tells its own story about where we are headed here in America, and why.

ColMosby, please give us a link to some credible body of cost & schedule feasibility analysis which describes how and when commercial scale molten salt reactors can replace the total of 37,000 megawatts of America’s legacy nuclear capacity which is expected to have been retired between 2010 and 2026.

Last edited 4 months ago by Beta Blocker
M__ S__
January 22, 2021 3:39 am

If it isn’t grandiose and it doesn’t waste a lot of resources the left isn’t interested.

Tom Abbott
January 22, 2021 4:15 am

From the article: “So is direct air capture worth the time and money?”

No, it is not. Anything to do with reducing CO2 is a waste of money because there is no need to reduce CO2.

Sara
January 22, 2021 4:51 am

But will it halt climate change? – article No, it won’t. It will exacerbate it.

Let’s do starve the plants to death, asphyxiate them, turn them into dead woody structures that are fuel for massive, raging wildfires. Absolutely BRILLIANT!!!!!

Have any of these geniuses ever heard of hyperoxia?

If you’re in a system that works and keeps you alive, why are you meddling with it?

If CO2 is a heat-trapping gas, it is probably the only thing staving off giant ice sheets and long periods of cold. If I have to live in a cave, I will invite a wolf pack to join me. They’re better hunters than these geniuses.

I will ask again: if you have a system that works, why are you meddling with it? Is your ridiculous ego really that weak?

Curious George
January 22, 2021 7:38 am

This is a beautiful inauguration present for President Joe Biden.

bigoilbob
Reply to  Curious George
January 22, 2021 11:42 am

I read the article twice and must have missed the mention of Biden.

This a silly, straw man. Carbon capture is the goofiest technically, economically worst, most impractical method available for reducing AGW emissions. The extractors are looking at it because they think they can get some/most of its costs communized on the rest of us, leaving them to produce more. The best path to ANY emissions reductions are source reductions…

January 22, 2021 7:56 am

They reinvented science to support the unsupportable, so reinventing the tree as a continuation of this insanity is just par for the course.

Gordon A. Dressler
January 22, 2021 7:58 am

What a fluff piece from the University of Sydney! . . . no offense to Eric Worrall intended, as he often relays humorous “information” showing the extent of sophomoric thinking from the various AGW/CAGW alarmist camps, including so-called centers-of-learning. In fact, as Eric himself states outside of the comments from Prof. D’Alessandro: “The idea of grabbing CO2 directly from the air just seems absurd when there are far more efficient alternatives available.”

I note that while D’Alessandro claims “The CO₂ is then concentrated, purified and compressed” there is no mention in the excerpts of what then happens to this compressed CO2. Is it cycled back for industrial uses (such as making soda pop beverages), or is there a plan to sequester it somewhere on Earth so that that small amount of CO2 is indeed “permanently” removed from Earth’s atmosphere?

Need I even mention the on-going scientific debate over whether or not there is strong scientific evidence that atmospheric CO2 is the predominant cause “global warming”?

shrnfr
January 22, 2021 8:00 am

Somehow, plants are cheaper and better. Besides, you can eat them.

accordionsrule
January 22, 2021 8:45 am

If they put it in the geothermal plant down the road and my plants die, I’m suing.

Brian Bellefeuille
January 22, 2021 11:03 am

Isn’t DAC also called a tree? Solar powered, and probably better to look at.
Oops, didn’t see that someone had already posted this. Great minds think alike.
But then, some Consultant will suggest that the trees be put into huge glass buildings, with likewise, huge fans to blow the CO2 onto the trees.

Last edited 4 months ago by Brian Bellefeuille
Michael S. Kelly
January 22, 2021 12:38 pm

It would be much easier to spray a wide area of ocean or lake water with cryogenic anhydrous ammonia from an air tanker just before the arrival of a major storm, such as a hurricane. The ammonia would be instantly absorbed into the surface of the body of water, where it would stay for quite some time. The storm would then deliver rainwater carrying dissolved CO2. Aqueous ammonia and CO2 would react to form (NH₄)₂ CO₃(s), which would precipitate out and sequester the CO2 at the bottom of the body of water. Ammonia could be manufactured by the Haber process (with the hydrogen coming from electrolysis of water) using nothing but “renewable” energy.

Simple.

Scissor
Reply to  Michael S. Kelly
January 22, 2021 2:10 pm

Even if the hydrogen is “renewable,” fossil energy is used to produce the catalysts and vessels used in addition the energy needed for operational compression and heating.

Michael S. Kelly
Reply to  Scissor
January 22, 2021 3:37 pm

I was being facetious, in anticipation of those who would be fatuous.

You are absolutely correct, and there are even more energy costs which can’t be provided by “renewables” (other than energy provided by fast breeder nuclear reactors, the ultimate renewable).

Haber process plants are extremely complex, energy intensive devices whose existence is owed solely to cheap fossil fuels. They produce more than 230 million tonnes of anhydrous ammonia per year worldwide, which is used directly as fertilizer, or converted to ammonium nitrate fertilizer (ammonium nitrate is much cheaper than the ammonium dayrate), or urea (to really piss off the left).

If you come across anyone who glibly rattles off a “solution” to atmospheric CO2 containing references to established technologies that can be “easily” adapted to the task, stop and think about it – as Scissor did.

DMacKenzie
January 22, 2021 1:36 pm

re potassium hydroxide…The “Hot Pot” process was once used for CO2 removal from natural gas, but less energy intensive, less hazardous, less corrosive processes are now used. To react with the low ppm of CO2 in air, the chemicals need to be strong bases. HazMat suits required. And somewhere to bury the corroded remains of your equipment.

Catcracking
Reply to  DMacKenzie
January 22, 2021 3:01 pm

About 8 years ago, I redesigned a badly designed apparatus to demonstrate the capture of CO2 from air. I dont require the chemistry because I am a mechinical Engineer but there are numerous alternative.
This was a cyclic process that blew air over a medium which adsorbed Co2, then gates at each end were closed and steam used to displace and collect the Co2 in an exhust outlet.
The big issue then was how you increase the pressure because that requires a lot of energy.
I have not followed up on any progress

Will_GaTech_ME
January 22, 2021 3:18 pm

Whenever you hear about CO2 reduction methods, always ask 1) what the CO2 reduction payback period is and 2) what the total lifetime net CO2 reduction. 1) How long does it take to remove/reduce CO2 in quatities sufficient to offset the CO2 released in the manufacture, delivery and setup of such methods (CO2 footprint). 2) Over the predicted lifetime of the device/method, what is the net reduction in CO2 after allowing for all the items in #1 plus footprint of maintenance, decommissioning and disposal. For some, I suspect the answers would be “never” and “negative”, so actually a net increase in CO2.

Jamaica
January 22, 2021 3:18 pm

why not just plant trees?

DMacKenzie
Reply to  Jamaica
January 22, 2021 8:04 pm

Trees already grew where the glaciers retreated…so it doesn’t seem to work…../s

Robert of Texas
January 22, 2021 7:17 pm

Umm… Don’t plants already do this? I’ll sell you tree seeds for $1,000 a piece and save you a ton of money over this plan!

michael hart
January 23, 2021 12:28 am

“Why bother with capturing concentrated CO2 from combustion exhaust, when you can spend “a wartime level of funding” capturing trace concentrations of CO2 directly out of the air?”

Yup. Hits the nail on the head. Extraction from high-dilution solution is always slow and energy intensive. Cost often rules it out but many people just don’t get. Like extracting gold from seawater, you can do it, and people have done it. But that doesn’t mean that you should do it. It’s easier to crush rocks to recover low-concentration gold than it is to extract it from extremely low concentration in sea water.

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