The truth about capturing CO2 to reverse climate change

The progress we’ve made recently with the adoption of renewable energy is encouraging, especially now that the effects of climate change are becoming more noticeable. But renewables alone won’t be enough to lower carbon emissions at the rate needed.

What if we could stop carbon emissions from entering the atmosphere in the first place by capturing it from pollution sources like a coal-fired power plant or a cement factory, and then storing it underground…or better yet, finding a use for it?

Well, we can do that with Carbon Capture, Utilization and Storage, or CCUS. And it’s not a new concept, but it’s been slow to take off — until now, that is. Numerous carbon capture facilities are being planned or built worldwide, so we could see this technology become much more common.

But do we really need it, how much of an impact could it really make, and is it in fact just an excuse to keep burning fossil fuels and let heavy polluting industries off the hook? It’s time to find out the truth.

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I’m Matt Ferrell. Welcome to Undecided.

The energy sector is now responsible for around three quarters of all greenhouse gas emissions so if we’re going to have any chance of hitting the targets that have been set for reducing these emissions, it’s crucial that the major industries in this field are doing everything they can to decarbonize.

While it would be great to shut down all the fossil fuel plants and immediately replace them with renewable alternatives, that simply isn’t possible. The transition has to be a gradual process, which means we’ll be stuck with some non-renewable sources in our energy mix for a while no matter what we do.

But that doesn’t mean we have to let these industries carry on polluting at dangerously high levels. With CCUS we can continue to burn oil and gas without having to worry about all those nasty emissions. Doesn’t sound too bad, right? And doesn’t it remove the pressure to make big changes right away when we can just bury it all underground for a while until we figure out the best way forward?

Well, one of the criticisms of CCUS is that it gives some industries and governments an excuse to do very little at a time when it’s critical we take action to address climate change. Despite that, this is a technology that we do need to start taking more seriously. In fact, the Intergovernmental Panel on Climate Change, or IPCC, has labeled CCUS a necessity — rather than simply an option — for keeping climate change under control. Alongside renewable technologies and new energy storage solutions, it looks set to become one of our main weapons in this fight.

And it’s not hard to see why. It’s estimated that approximately 90% of the emissions generated by large-scale industrial processes can be captured, so it can be very effective¹. It actually works best in these situations too — where high concentrations of CO2 are present. At coal-fired power stations it is thought to be possible to capture at least 800,000 tons of CO2 per year, whereas natural gas plants (which produce less CO2), can offer over 400,000 tons of extractable CO2².

This is done by filtering out the CO2 from the flue gases using special solvents before it enters the smokestack. Another process involves sucking up carbon dioxide that is already in the atmosphere through what is called direct air capture — a form of negative emissions technology³.

While it might sound like an advanced concept, CCUS has been going on for some time. The idea for the first carbon capture plant came back in 1938, but the first major project to involve burying CO2 underground didn’t take place until 1972 in Texas. It took another 24 years for the first combined carbon capture and storage solution to come about — in the North Sea around Norway⁴. So, the theory has been around for nearly a century now, but there are large gaps between the major milestones and progress has continued to be very slow.

There are only two large-scale coal-fired power plants in the entire world that have CCS capabilities – NRG’s Petra Nova in the US and Canada’s Boundary Dam, owned by SaskPower. These are just the kind of facilities that we really need to get on board with carbon capture and they were both retrofit projects — so not new builds⁵. Overall, the International Energy Agency, or IEA, says there are only 18 large-scale CCUS facilities operating worldwide – so this covers more than just coal-fired plants – and collectively they capture around 33 million tons of CO2 per year. This sounds like a lot, and it is, but it still only amounts to 0.1 percent of the total carbon emissions worldwide.

We can’t realistically expect to be able to capture all carbon emissions when they come from such a variety of other sources as well, such as transport and housing, but it’s clear that a lot more needs to be done before CCUS can be considered a major contributor to emission reduction. Nevertheless, the IEA is optimistic about the technology and foresees a future where CCUS facilities will be capturing 115 gigatons of CO2 by 2060⁶.

Why, then, is it taking so long to get going? A big reason why it hasn’t taken off as quickly as it could, and perhaps should have done by now, comes down to that one thing that makes or breaks, well, pretty much everything in life — money.

Capturing and storing carbon might be great for the environment and the future of our planet, which you’d like to think would be enough on its own, but it’s not exactly a lucrative business at the moment and it’s not easy for companies to make a profit from it, especially when it’s currently a very expensive process.

There are also concerns about the availability of sites worldwide where CO2 can be stored once it’s been captured. Some areas, such as the North Sea in Europe, are ideal locations for subterranean storage, but the same can’t be said for every country in the world that is under pressure to drastically lower their emissions and could benefit from this kind of solution. Some critics also argue that burying it underground is too risky since it could leak out of the reservoirs and either back into the air or into water supplies. Another unintended consequence could be a build-up of pressure underground leading to man-made tremors — known as induced seismicity⁷.

And how much of this do we actually need to be doing? Is there a target we should be aiming to hit? Estimates vary on the total capacity required to meet climate change targets. Some reports say as much as 10,000 gigatons (Gt) will be needed globally, but Imperial College London has recently done its own calculations to conclude that only 2,700Gt will be necessary, and that we’re actually on track to achieve this looking at current progress⁸.

Going back to that issue of money, one way to make a few bucks with captured carbon is to turn it into a product that others can put to some kind of use. This is the utilization, or ‘U’ part of CCUS. The process of making CO2 into an economically valuable product involves either transforming it into materials, chemicals and fuels through certain reactions or keeping the CO2 as it is and utilizing it in techniques such as enhanced oil recovery⁹. This is where carbon dioxide is used to flush more oil out of wells and reservoirs than what can normally be extracted through conventional means. Others are taking a more environmentally friendly approach, such as Climeworks, a Swiss start-up, that is using direct air capture to remove CO2 from the air and sell it be used for fertilizer or carbonated drinks¹⁰.

One of the most promising uses for captured CO2 though might surprise a few people: building materials. CO2 can quite easily be turned into a solid aggregate for use in concrete without generating much energy at all. It can also be infused into wet concrete to help cure it as the CO2 reacts with the water and calcium, forming solid calcium carbonates. This means that CO2 can be sequestered, or hidden away, in walls and floors for the entire lifetime of the built structure and it reduces the carbon footprint of concrete production too, which is responsible for around eight percent of greenhouse gas emissions¹¹.

Another way of making CCUS a more attractive business prospect is creating incentives through new policies. In 2018, the US Congress introduced a tax credit that rewards companies for each metric ton of CO2 that they capture and store, while there are also new California laws that offer incentives to firms that take steps to sequester their carbon dioxide. Even if a lot of this CO2 is then used to extract more oil and gas from the ground, which is true in many cases, at least it gets more CCUS operations up and running¹².

While the issue of money — both in terms of cost and profitability — is one of the main barriers to widespread adoption of CCUS, the technology is steadily being deployed more and more, which will start to push costs down. The US is the current world leader in the development and deployment of CCUS, and Minnkota Power Cooperative is now aiming to build the world’s largest carbon capture facility with its new Project Tundra project. This would see North Dakota’s Milton R Young station retrofitted with amine-based technology for post-combustion capture which would make it capable of collecting 4 million tons per year of CO2¹³.

Europe is another hotspot for CCUS innovation. Energy giants Shell, Total and Equinor have submitted plans to build the world’s first CCS network off the coast of Norway. The $685 million Northern Lights project is thought to be capable of eventually capturing and storing up to 5 million tons of CO2 a year from some of the biggest emitters in the EU with its giant saline aquifer. These can be thought of as huge underground salt water deposits, which react with the CO2 once injected to form solid materials, preventing it from unintentionally re-entering the atmosphere as a gas¹⁴. With Northern Lights, CO2 would be collected from capture sites across Europe — again using amines — and then shipped to an island-based terminal near Bergen where it is kept in temporary storage tanks before being injected into a subsurface reservoir 2,700 meters below the seabed. The project is set to become operational in 2024 once signed off by the Norwegian authorities¹⁵.

What is amine-based technology? Well, some methods of carbon capture involve the use of alkylamine solutions — or amine for short – to separate and remove harmful compounds such as CO2 from flue gases. They are a highly effective way of capturing high-purity CO2 and is used more commonly than any other method in large-scale CCS projects¹⁶.

But this isn’t the only approach, and new innovations are starting to appear more regularly. Engineers at the Massachusetts Institute of Technology have come up with a way of removing CO2 no matter the concentration – so from the heavily concentrated flue gases of a power plant right down to direct capture straight from our atmosphere. Extracting from low concentrations is much more difficult — in power plants, between 10%-20% of the gas from a smokestack is CO2, but in the air it’s as little as .04% so it’s much harder to “grab”⁴.

MIT’s new method promises to be a much more efficient and cheaper way to capture in low-concentration scenarios. It involves directing air through a series (or a stack) of electrochemical cells plates, which work like a special type of battery that sucks CO2 out of the air as it passes over its electrodes when it charges, and then releases the gas as pure CO2 when it discharges¹⁷.

Meanwhile, researchers at Monash University in Melbourne and CSIRO, Australia’s national science agency, have discovered a CCUS method that they claim sets new standards in efficiency. It involves using small amounts of a cutting-edge material called Metal Organic Frameworks, or MOFs, which have incredibly large surface areas. An MOF is a crystalline compound of metal ions that behaves a bit like a sponge filled with tiny magnets, and it has unusually porous properties. Its low energy cost is achieved via an absorption process similar to heating an induction cooktop to reduce the overall energy required.

The Australian scientists have made their own unique, highly absorbent material using MOFs that can regenerate extremely quickly as well as use very little energy. This, they say, would make it a relatively cheap method, and they’re aiming to be capable of capturing CO2 directly from the air in the future.

While there’s still work to be done to iron out the issues and we have yet to see it reach its full potential, carbon capture, utilization and storage surely has some part to play in our collective mission to slash greenhouse gas emissions. More governments and corporations are getting on board, but perhaps not as quickly as required, and some argue that the oil and gas industry could also do more. Even taking the lead in this space since they have the financial means and the engineering know-how to drive CCUS innovation forward¹⁸. Despite all of this, if we can create those incentives to make it more financially viable, increase the number of projects and continue to discover new ways of doing it, especially with direct-air capture, then CCUS might just be the boost we need to get on top of this climate crisis.