Sunday, November 29, 2020

Direct air capture: Giant machines that can suck CO2 out of the atmosphere could help control pollution levels

This month, the Government pledged £1bn to the creation of four industrial carbon capture clusters, which will trap emissions from industry


By Madeleine Cuff
November 28, 2020
Technicians inspect the direct air capture system at the Carbon Engineering Ltd. pilot facility in Canada (Photo: James MacDonald/Bloomberg/Getty)


From the rocky outcrops of Iceland to the to the sunny plains of Texas, engineers are building giant machines to suck carbon dioxide out of the atmosphere. It sounds like science fiction, but the companies behind this technology insist it could be a secret weapon in the fight against climate change.

The world has dithered for too long over the task of cutting greenhouse gas emissions, and scientists agree global climate targets are slipping out of reach. To keep warming below 1.5°C – the “safe” climate threshold – and maintain the perks of modern life, the world will have to work out a way to remove between 100 and 1,000 gigatonnes of CO2 from the atmosphere during this century, experts say.

“In all the analysis which maintain anything like our present lifestyle, we will end up doing 10-20 per cent of negative emissions,” Professor Stuart Haszeldine, an expert in carbon capture technologies at the University of Edinburgh, tells i. “The only way we can avoid that is if we stop flying, don’t have motorcars, the remaining vehicles are all public transport and electric, and we only eat meat once a week, if that. You can avoid this, but it means quite large lifestyle changes for all of the population.”


Trees absorb CO2, but there isn’t enough land on the planet to create a carbon sink the size humanity needs. So while we need to plant trees and protect the world’s remaining forests to tackle climate change, we will also need technology to help us remove excess carbon from the atmosphere.

Enter direct air capture (DAC). It is an offshoot of carbon capture and storage, whereby pollution from factories and power plants is trapped and stored underground. DAC takes that one step further, focusing on pulling the gas directly from the air. That is a tougher ask, because CO2 in our air is at much lower concentrations than in the flue gases of a power plant. But if DAC technology can scale, it could give humankind the power to control global pollution levels.

There are signs a breakthrough might be close. Swiss firm Climeworks has built a handful of DAC plants across Europe. Orca, under construction in Iceland, will be the world’s biggest facility when it opens next year, capable of removing four million tons of CO2 every year. Canadian rival Carbon Engineering, meanwhile, is building a plant that could suck away a million tons a year.

At Carbon Engineering’s plants, the extracted CO2 is bound to other molecules to create calcium carbonate (Photo: James MacDonald/Bloomberg/Getty)

How it works

Both Climeworks and Carbon Engineering use chemical reactions to bind CO2 molecules, drawing them away from the other gases that make up our air. The CO2 can then be pumped underground for storage or used with hydrogen to make low-carbon fuels.

In the UK, the captured CO2 is most likely to be pumped into spent oil and natural gas fields in the North Sea. There is little need to worry about it escaping once it has been stored, says Professor Haszeldine. “We know how to do this,” he says. “We know what the engineering is. And most importantly we know how to behave and remediate this if something does go a bit wrong.”

Climeworks is partnering with Icelandic start-up Carbfix to store its CO2 safely in basalt rock. “Even if you have an earthquake or a volcanic eruption, it cannot come out again,” says Christoph Beuttler from Climeworks.
Climeworks is storing its captured CO2 in basalt rock
 (Photo: Climeworks)

Who foots the bill?

It is still early stages for DAC – there are only 15 plants in North America and Europe – and the tech remains very expensive. Costs should come down, however, as efficiency improves. Climeworks thinks it can reduce the cost of extracting a ton of carbon dioxide from $1,000 to $100 within a decade.

But DAC is never going to be a cheap option. “The fact is, it is going to be easier to decarbonise a lot of industrial processes than it is to build an entire sector from a standing start,” says Dr Mark Workman, a carbon storage expert at Imperial College London.

There is also fierce debate over who will pay for it. Most experts think governments will have to force the creation of a new market. That could be in the form of a subsidy regime, or with legislation to force fossil-fuel producers to arrange for storage.

A hike in VAT to pay for the pollution caused by goods and services has also been mooted, placing the cost on a public who, Dr Workman argues, are not prepared for the scale of such a challenge. “We are going to remove an invisible gas and store it in invisible storage sites. And we are going to be taking vast quantities of public money – tens, if not hundreds of billions of pounds,” he says. “There really does need to be a much broader social dialogue about this.”

DAC will be a crucial tool for fighting climate change. Most scientists agree we can’t keep temperatures under 1.5C without it. But it will not be a silver bullet for our planetary problems, not least because we don’t yet know how to pay the bill. 

Climeworks is building its biggest site yet in Iceland
(Photo: Climeworks)

Can DAC reverse climate change?

Scientists are split on whether DAC machines can help to reverse climate change. Just getting to net-zero will be a daunting task, requiring this tiny industry with early-stage technology to grow bigger than the entire oil and gas sector in just three decades. To enter net negative emissions would be an even greater financial and technical challenge.

The world’s waters could pose another hurdle. Oceans absorb huge amounts of CO2 pollution. Taking CO2 out of the atmosphere may prompt oceans to release some of their own stores back into the air. It means that for every step forward engineers take in removing CO2 from the atmosphere, this “ocean rebound” effect could force them half a step back.
The Direct Air Capture industry will need to grow at least as big as the current oil and gas sector if the world is to meet its climate targets 
(Photo: James MacDonald/Bloomberg/Getty)

Direct Air Capture in the UK

The Government is hoping the UK’s vast network of empty oil and gas fields under the seabed will turn us into a global leader in carbon storage. Last week it promised £1bn towards the creation of four industrial carbon capture clusters, that will see emissions from heavy industry trapped and piped out to sea for storage.

In St Fergus on the East Coast of Scotland, Pale Blue Dot Energy wants to build not only a CCS hub for Scotland, but the UK’s first Direct Air Capture system to boot. It has teamed up with Canadian firm Carbon Engineering to get a direct capture site up and running by 2026, managing director Paul Allen tells i.

“When you’re going on holiday to Tenerife or Turkey or wherever, how do you capture the emissions that come out of your RyanAir or Easyjet flight? It’s difficult to do,” he says. “Those are the types of customers that will be able to make use of the Direct Air Capture system.”

But Pale Blue Dot Energy might face a race against time if it wants to be the UK’s first DAC plant. Climeworks tells i the Government’s funding announcement last week means it is now considering an expansion into the UK.

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