Direct Air Capture (Technology Factsheet)


Direct Air Capture (DAC) is a largely theoretical technique in which CO2 (and potentially other greenhouse gases) are removed directly from the atmosphere. The current technique uses large fans that move ambient air through a filter, using a chemical adsorbent to produce a pure CO2 stream that could be stored. To have any significant effect on global CO2 concentrations, DAC would need to be rolled out on a vast scale, raising serious questions about the energy it requires, the levels of water usage for particular technologies, and the toxicity impacts from the chemical sorbents used. In addition, safe and long-term CO2 storage cannot be guaranteed, either in geological formations where leakage is a risk (see CCS factsheet1) or in products using CO2, where carbon is likely to end up back in the atmosphere one way or another (see CCUS factsheet2). The fossil fuel industry is attracted to DAC because the captured CO2 can be used to for Enhanced Oil Recovery (EOR), especially where there is not enough commercial CO2 available locally.

At a DAC summit in Calgary in 2012 there were a number of oil companies in attendance, including Suncor, BP, Husky Oil, and Nexen

Actors involved

DAC is a commercially active geoengineering technology. David Keith’s company Carbon Engineering is funded by private investors including Bill Gates and Murray Edwards, the billionaire tar sands magnate who runs Canadian Natural Resources Ltd (Keith is a prominent US-based geoengineering researcher and proponent). Carbon Engineering opened an CAD$ 8 million pilot plant in Squamish, British Columbia in 2015, where they claim to extract about a tonne of carbon dioxide a day.3 Carbon Engineering also plans to turn captured CO2 into transport fuels, which then re-emit CO2 into the atmosphere when they are burned.4

Swiss company Climeworks says they have created the “first commercial plant to capture CO2 from air” in Zurich.5 They claim the US$ 23 million plant is supplying 900 tonnes of CO2 annually to a nearby greenhouse to help grow vegetables. They have partnered in Iceland with Reykjavik Energy at the Hellisheidi geothermal plant to run one of their air capture units (with capacity to capture 50 tonnes of CO2 per year) and inject CO2 into basalt formations. This project, CarbFix2, has received funding from the European Union’s Horizon 2020 research and innovation programme.6 Reykjavik Energy, and in particular the Hellisheidi geothermal plant, have been the focus of large-scale environmental protests in Iceland for causing serious harm in what is Europe’s last remaining area of wilderness.7

Other companies developing DAC include Global Thermostat, bankrolled by Goldman Sachs, and partnered with Algae Systems,8 as well as Skytree in the Netherlands and Infinitree (formerly Kilimanjaro) in the US.9

David Keith and other developers have pitched DAC as a means to use captured CO2 to massively scale up the EOR industry in the US and elsewhere. At a DAC summit in Calgary in 2012 there were a number of oil companies in attendance, including Suncor, BP, Husky Oil, and Nexen.10 However, optimism for DAC’s business case is belied by the reality that it is not economically feasible due to high costs,11 which are likely to be more than 4 times greater than other Carbon Dioxide Removal approaches.12 Moreover, using DAC to enable EOR would obviously cancel any supposed climate mitigation benefits.13

DAC technology has attracted the attention of venture capitalists like Ned David, who is keen on EOR and runs an algae synthetic biology company. He hopes to create biofuels by feeding captured carbon to algae produced in giant vats outdoors and has sought funding from Monsanto.14

Direct Air Capture would be likely be used for Enhanced Oil Recovery, and would incur significant energy costs and divert resources from alternative energy sources. There would also be a significant risk of the CO2 leaking back into the atmosphere, potentially causing ecological damage.


DAC requires considerable energy input. When including energy inputs for mining, processing, transport and injection, energy requirements are greater still, perhaps as much as 45 gigajoules per tonne of CO2 extracted.15 For David Keith’s pilot DAC unit, this is the equivalent of running it off a constant 0.5 megawatt power supply.16 Neither Climateworks nor Carbon Engineering publish the energy requirements of their units, and in the case of Carbon Engineering, it is not known how the electricity powering the unit is produced. Because of the huge demand for energy that DAC implies, some geoengineering promoters have proposed to use “small nuclear power plants” connected to DAC installations, 17 potentially introducing a whole new set of environmental impacts.

DAC also requires substantial water input. One study estimates that at implementation levels that would remove 3.3 gigatonnes of carbon per year, DAC could expect to use around 300 km3 of water per year (assuming current amine technology, which is what Climeworks uses). This is equivalent to 4% of the water used for crop cultivation each year. DAC technologies using sodium hydroxide (Carbon Engineering) would use far less,18 but this in turn is a highly caustic and dangerous substance.

Washington State Governor Jay Inslee inspects a Climeworks DAC unit in Switzerland (Jay Inslee/Creative Commons)

A modelling exercise looking at the impact of DAC on climate stabilization efforts predicted that it would postpone the timing of mitigation (emissions reductions) and allow for a prolonged use of oil, impacting positively on energy exporting countries.19 This is of course similar for many geoengineering technologies and one of their most dangerous aspects.

Reality check

There is one demonstration facility near Zurich owned by Climeworks,20 and another by the same company in Iceland.21 Carbon Engineering also operates a pilot plant in British Columbia.22 In addition there are several companies that have developed small-scale capture units, with numerous research projects also underway.

Further reading

ETC Group and Heinrich Böll Foundation, “Geoengineering Map.”

The Big Bad Fix: The Case Against Climate Geoengineering,


1. See Geoengineering Monitor, “Carbon Capture and Storage,” Technology Fact Sheet, April 2018.

2. See Geoengineering Monitor, “Carbon Capture, Use and Storage,” Technology Fact Sheet, April 2018.

3. John Lehmann, “Could this plant hold the key to generating fuel from CO2 emissions?” The Globe and Mail, 2017,

4. Carbon Engineering, “Carbon to fuels,”

5. Alister Doyle, “Scientists dim sunlight, suck up carbon dioxide to cool planet,” Reuters, 2017,

6. ClimeWorks, “Climeworks and CarbFix2: The world’s first carbon removal solution through direct air capture,” 2017,

7. Saving Iceland, “Hellisheidi: a geothermal embarrassment,” 2017,

8. Algae Systems, 2017,

9. Infinitree, “Carbon Capture Greenhouse Enrichment,” 2017,

10. Marc Gunther, “The business of cooling the planet,” Fortune, 2011,

11. Marc Gunther, “Direct air carbon capture: Oil’s answer to fracking?” GreenBiz, 2012,

12. Derek Martin et al., “Carbon Dioxide Removal Options: A Literature Review Identifying Carbon Removal Potentials and Costs,” University of Michigan, 2017

13. Marc Gunther, 2012,

14. Katie Fehrenbacher, “Algae startup Sapphire Energy raising $144M,” Gigaom, 2012,

15. Pete Smith et al., “Biophysical and economic limits to negative CO2 emissions,” Nature Climate Change, 2015

16. W=J/t, therefore 45GJ / 1 day in seconds = roughly 500,000W

17. Proposed by David Sevier, Carbon Cycle Limited, UK; communication in a geoengineering electronic discussion group, September 2017

18. Pete Smith et al., 2015

19. Chen Chen and Massimo Tavoni, “Direct air capture of CO2 and climate stabilization: A model based assessment,” Climatic Change, Vol. 118, 2013, pp. 59–72

20. Christa Marshall, “In Switzerland, a giant new machine is sucking carbon directly from the air,” Science,  2017,

21. ClimeWorks, “Public Update on CarbFix,” 2017,

22. John Lehmann, 2017

Climate Change Policy and The Super-Hero Syndrome

Jeremy Thompson/Wikimedia Commons CC BY 2.0
Jeremy Thompson/Wikimedia Commons CC BY 2.0

by Roger Boyd (Resilience)

There is a genre of Hollywood “feel-good” disaster movie, where everything seems nearly hopeless until the end, and then suddenly, many times against all hope, the super-hero (or super-heroes) saves the day. Whether it be human heroes that blow up the Earth-killing asteroid just in the nick of time; good mutants that defeat the bad mutants just in time; bad mutants turned good mutants that destroy the stayed-bad mutants just in time; future humans and non-human allies that save the Galaxy from the Empire. Anyway, you get the general storyline. The bad people/organisms /things win for the first 95% of the movie then the good people/organisms/things win against all the odds in the last 5%.

The United Nations Climate Change bureaucracy, which tends to be full of economists, engineers and enviro-managers rather than actual climate scientists and ecologists, seems to have been watching too many of these feel-good disaster movies. Seems we need to make them watch the “feel bad” disaster movies instead, like the one where the Sun eats up the Earth, or perhaps a steady diet of the unlimited supply of zombie apocalypse movies. They need something a lot darker, where super-heroes don’t save the day. Then again, maybe they should just grow up and accept that super-heroes only exist in movies. Or maybe they should just listen to the scientists and ecologists a lot more.

The United Nation’s main super-hero is called BECCS (Bio-Energy Carbon Capture & Storage). I know, not exactly as catchy as Superman, Thor, Cat Woman, or Wolverine, but what would you expect from a bunch of climate bureaucrats? BECCS is a true super-hero. The Bad Carbon will continue spewing itself into our atmosphere for decades to come, threatening to remove the ecological basis for modern human civilization. BECCS’s friends, Energy Efficiency and Clean Power, will have held back Bad Carbon a bit, but could not stop BC in time! Then at the last minute, just before human civilization melts down, BECCS sucks up BC and deposits it deep in the Earth never to return (well at least for a few thousand years hopefully).

The problem is that BECCS is not real; it’s a bunch of hopes and a religious belief in technology wrapped together. It assumes that we can set aside about a third of the current arable land on the planet to grow energy crops, instead of food. Then we can burn all those energy crops to help power our modern civilization, and can store all of the resulting carbon dioxide (billions of tons of the stuff) underground safely for thousands of years. That’s a lot of carbon dioxide per year, needing an infrastructure equivalent to the current oil & gas industry to transport it and pump it into the ground. What tiny-scale testing of the CCS (Carbon Capture and Storage) part of BECCS that has been carried out so far could most politely be described as “deeply disappointing”.  Ignoring this, the U.N. people assume that BECCS will start riding to the rescue on a major scale within 20 years or less.

What if BECCS isn’t up to the task? Other eco-technocrats have an army of super-heroes ready to help. These eco-techies seem to be into super-hero ensemble movies – maybe we should call them “The C-Men”. If EE, CP and BECCS cant beat the deadly BC, there is always – wait for it, drum roll please… DAC!!!! (Direct Air Capture) will save the day! BECCS couldn’t suck up enough of the highly concentrated carbon dioxide at the power plant exhaust, but DAC can get enough of it after it has become highly diffuse in the air! If that doesn’t work there is EW (Enhanced Weathering: dig up truly colossal amounts of a certain type of rock, turn it into powder and spread it over the Earth), OF (Ocean Fertilization: fertilize carbon capturing organisms in the ocean), and SRaM (Solar Radiation Management: block/reflect the Sun’s energy to cool the planet).

Why do we need all these super-heroes? Because without these super-heroes we would have to accept that large-scale government intervention will be required to fundamentally change our societies to use a lot less energy. A lot like a war-style economy. A lot less belief in “free markets”, perhaps no economic growth for a while, a ton of pressure for a more equitable sharing of income and wealth, and a lot less use of fossil fuels. Not a reality that the powers-that-be want to deal with. So we get the mythical super-heroes instead.

Those that consider a Trump presidency to be a disaster do not understand that we are already in the disaster. Trump may speed up the disaster a little and is certainly more “in your face”, but he is just a symptom of a larger problem. In a way, you could say he is being a bit more truthful about his version of reality-denial. The problem is the inability of even the “progressives” among the powerful to accept the reality that the time for small measures is gone, and that drastic action is required now. In the early 1990’s, those actions may have been relatively mild. Now, they are much bigger and the longer we wait, the bigger and riskier they get. Only denial, facilitated by mythical technocratic future super-heroes, can keep us from this truth.

More funding being made available for negative emissions nonsense

Ecosystem-destroying eucalyptus plantations would be a key part of a bioenergy with carbon capture and storage (BECCS) climate mitigation strategy. Chris Lang/Flickr CC
Ecosystem-destroying eucalyptus plantations would be a key part of a bioenergy with carbon capture and storage (BECCS) climate mitigation strategy. Chris Lang/Flickr CC

A UK research fund has recently announced that £8.3m is being made available to fund up to 10 different research projects for a programme on Greenhouse Gas Removal from the Atmosphere.

Examples given as potential topics for research proposals are:

  • Soil carbon, forestry and land management, to include biochar
  • Bioenergy with carbon capture and storage (BECCS; may include forest-based feedstock)
  • Enhanced weathering and ocean alkalinity enhancement
  • Direct air capture (DAC)

Whilst “soil carbon, forestry and land management” is very broad, no where in the supporting documentation are terms like “natural ecosystem regeneration” or “agro-forestry/ecology”. These are proven and low-cost methods of removing carbon from the atmosphere, that have been put into practice by communities across the globe (with very little support and funding) for decades. But the serious contribution they could make “at a climatically-relevant scale” is simply ignored in favor of unproven, untested and (in the case of biochar and BECCS at least) nonsense technology.

As we recently reported, the Paris Agreement has been a major boost for proponents of negative emissions technologies. Industry calls for more funding are being answered, and it is likely that far more funding will be made available in future for such projects.

With the global climate crisis in the state that is currently is – take for example the recent studies that show there may already be too much carbon in the atmosphere to meet the 1.5 degree target set out in Paris only last December – putting millions into pointless research, when there’s so much that needs to be done in terms of drastically reducing emissions, is simply unacceptable.

Artificial leaf turns carbon dioxide back into carbon dioxide – and this is somehow helping to fight climate change?

Perfectly good, non-artificial leaves. Micolo J via FlickrThis week’s headline news from the world of technofix climate solutions is that a team of researchers led by the University of Illinois-Chicago has developed an artificial leaf. This leaf is a solar cell that uses the power of the sun to mimic photosynthesis and converts carbon dioxide into a fuel. Whereas a real leaf sucks up carbon dioxide and turns it into more tree, this artificial leaf turns it into a gas that can then be burned, releasing the carbon back into the atmosphere.

Climate Central’s story on this research lead with the line: “If humans could invent a leaf-like solar cell that could turn carbon dioxide pollution from the atmosphere into fuel for electric power plants, it could help reduce reliance on fossil fuels and cut emissions that contribute to global warming.”

Which is really quite amusing, given that millions of years of evolution has provided us with a perfectly adequate and natural leaf-like solar cell that can turn carbon dioxide pollution from the atmosphere into fuel, and certainly helps cut emissions that contribute to global warming.

Most uses of leaves and trees as fuel in electric power plants do make climate change worse of course, but humans have also been sustainably managing woodland on a small scale for thousands of years, such that forests and soils keep sequestering carbon, and humans get fuel and shelter. The key issue here being scale.

Here’s a thought: What if all of the research money currently being ploughed into false climate solutions, such as this artificial leaf, carbon capture and storage, and technologies involving solar radiation management or direct air capture, was put towards genuine and proven climate solutions instead, like regenerating natural ecosystems that have plants and trees with non-artificial leaves, and agro-ecology, where the trees and plants also have real leaves?

Maybe if we stop destroying perfectly good real leaves that already do a great job of removing carbon pollution from the atmosphere, no one will think there’s a need for artificial ones? Perhaps if governments and industry took climate change seriously and actually started drastically reducing greenhouse gas emissions, we wouldn’t even be talking about these ridiculous ideas.