It’s 2023. We’re still not making the most of carbon capture, utilization, and storage

In the collective effort to fight climate change, CCUS (Carbon Capture, Utilization, and Storage) is one of the few frontline tools. Today, carbon dioxide (CO₂) is captured directly by power generation or industrial facilities, or even directly from the atmosphere. The captured CO₂ is then utilized or stored. If stored, it’s injected into deep geological formations for permanent storage. If utilized, carbon can be incorporated into several production processes.

But how many of us are aware of the size and scale to which CCUS is taking place in this day and age – and what happens to the carbon when it’s captured?

By capturing carbon dioxide emissions at their source, CCUS helps mitigate the overall effects of accumulated carbon in our environment. CCUS has its roots in decades of scientific exploration – back to the 1930s. Official figures from bodies like the International Energy Agency (IEA) reveal a significant increase in CCUS projects globally, with over 30 large-scale facilities in operation or under construction (as of the end of 2020).

There is an estimated global CO₂ emission of 33 billion tons per year. The global capacity for carbon capture in 2021 was 43 million tons per year, accounting for just 0.1% of the emissions. The target is for CCUS to reach 10 billion tons per year by 2050, removing a third of our annual carbon emissions. While capacities are increasing year by year (the next goalpost is 279 million tons of CO₂ captured annually by the end of 2023, according to BloombergNEF’s report), very little of that captured CO₂ has been applied in innovative, practical, or useful formats.

Most of the captured carbon at present is pumped into storage wells underground – that’s the ‘S’ in CCUS, but not enough has been done for the ‘U’. Annually, only an estimated 270 million tons per year of CO₂ have been used, mostly on fertilizers, food, metal fab, and concrete. Yet for some of these uses, the CO₂ is re-released back into the atmosphere upon use, defeating the purpose of capturing it in the first place.

This is doubly inefficient: let’s not forget that CO₂ storage facilities need to be maintained and often occupy a very large area that isn’t used for any other purpose.

With 270 million tons/year of CO2 used versus 37 billion tons/year of CO2 emitted – we have a very long way to go.

CO₂: a useful yet misunderstood element

Earth’s CO₂ issue really is about too much of a good thing. Despite the negative climate-related connotations, CO₂ primarily is a very useful element and potential resource. Aside from the need for plants to achieve photosynthesis to produce oxygen, everything on earth is carbon-based.

As the Scientific American mentions, carbon is “the most versatile, most adaptable, most useful element of all. Carbon is the element of life.” 

From the chart we can see that carbon, through conversion, can be applied into fuels, to chemicals, to building materials, and so on. Direct uses of carbon include crop yield boosting, heat transfer media, or applications in food, welding, medicines, and more. The usefulness of carbon is remarkably broad, with plenty of potential waiting to be untapped.

Carbon has the ability to form stable bonds with many elements, including itself. This property allows carbon to form a huge variety of very large and complex molecules. In fact, there are nearly 10 million carbon-based compounds in living things. 

Take for example, the Chimei Asai facility in Taiwan, a joint venture of Asahi Kasei Chemicals and Chi Mei Corp. They have been manufacturing around 150,000 tons of polycarbonates per year using CO₂ as a starting material for over a decade. 

And at the price of $15 to 100 per ton, carbon as an abundant resource isn’t expensive at all. Being so affordable, we believe more research can be done to use carbon as a resource for practical outcomes.

Carbon utilization and removal pathways

To understand what we can work with when it comes to handling carbon, we have to understand the different formats of carbon capture: Closed, Cycling, and Open Pathways.

Of the three methods, ‘Closed’ is the most conservative, practical, and commonplace. ‘Cycling’ and ‘Open’ have their uses, but both require a large investment in time and resources to make it practical.

There are three methods to utilize captured carbon:

1) CO₂ Splitting: CO₂ can be split into different components, leading to various applications.

2) Synthetic Biology (synbio): CO₂ can be absorbed by microbes/algae to produce chemicals, food, or feedstock to make products.

3) Direct Incorporation: CO₂ can be directly incorporated into products.

Splitting carbon to make chemicals and fuels

Electrochemical splitting of CO₂ can create useful chemicals, such as syngas, Formic acid, Oxalic acid, and more. However, as CO₂ is an inert molecule, the science behind splitting carbon is very complex and expensive. Efficiency rates are also very low, often ranking below 50%. The molecule-splitting process also requires plenty of water. If we consider the cost and complexity of the entire process, it’s more efficient to use electrolysis to create hydrogen, a more energy-dense fuel that’s gaining traction globally.

Converting CO₂ into liquid fuels that substitute gasoline or diesel fuel only locks in carbon until the fuel is combusted, at which point it is re-released into the atmosphere.

Synbio process to produce fuels, chemicals, food, and materials

The synbio route is an interesting one, where startups use genetically modified microorganisms to absorb carbon to create useful chemicals.

Examples include using microbes to produce useful chemicals such as bioethylene or glucose. Copious amounts of carbon can also be used to accelerate algae growth, to turn it into an abundant feedstock to make food, biofuels, plastics, or even carbon fiber. But the systems are complex, requiring AI-powered photo-bioreactors for biomass production, requiring at least a two-stage dewatering process.

Generally, the science, research, and development behind using Synbio to decarbonize our climate is extremely expensive and complex, with many companies exploring this space going under.

Direct incorporation of carbon into things we live with

Direct incorporation is a much more practical method of making use of CO₂. Today it’s part of the cement-production process, which ‘locks in’ carbon for much longer. Concrete won’t permanently keep CO₂ out of the atmosphere, but can store it for a century or more, which counts as a form of effective carbon storage. The Nature paper calls these “closed” processes.

As the Nature paper says: “Cement requires the use of lime (CaO), which is produced by the calcination of limestone in an emissions-intensive process. As such, unless calcination is paired with carbon capture and sequestration, it is difficult for building-related pathways to deliver reductions in CO₂ emissions on a life-cycle basis.”

Ironically, cement production itself emits carbon, which needs to be captured and sequestered to make it carbon-neutral. With economies and standards of living around the world improving, and real estate constantly developing, cement production is now the seventh highest emitter of carbon into the atmosphere, with energy production taking the number one spot. So that presents a paradox to the solution.

Another common use of captured CO₂ is incorporation into fertilizers. However, once the fertilizer is placed in the soil, it’s re-released into the environment within weeks.

So, all that investment and effort in carbon capture and utilization vaporizes in just weeks. Is there any point in that?

Locking carbon into a material that doesn’t degrade: plastic

It’s a challenging goal: make use of abundant captured carbon, don’t let it reintegrate with our climate, and ensure it makes no additional contribution to carbon emissions in the process.

One highly plausible solution we’ve studied over the years is to incorporate carbon in something that’s very common in our everyday living: plastics.

As the IEA puts it: “CO₂-derived products that involve permanent carbon retention, such as building materials, can offer larger emissions reductions than products that ultimately release CO₂ to the atmosphere, such as fuels and chemicals.”

More accurately, carbon can be incorporated in polyol, a raw material that’s used to make plastics/PU/surfactants. These become useful materials that we use commonly, and often for a very long time: shoe soles, car seats, insulation, beds, paints, and more. When incorporated into plastics, it keeps carbon locked away for long periods, just like carbon in concrete.

As for the production process, making traditional plastics contributes to carbon emissions (though not as much as the concrete-making process). That’s because traditional plastics rely on fossil-based feedstocks. The aim of incorporating captured carbon in plastics is to replace these fossil-based feedstocks, effectively cutting down carbon emissions in the process.

From the above chart, it is clear that the most practical and profitable use of CO₂ is incorporation into polyol, a raw material for plastics. A UK startup that’s been developing this method effectively is Econic, which uses a catalyst to incorporate carbon into the PU production process. Best of all, it doesn’t call for additional energy requirements (keeping it carbon-neutral), and it fits seamlessly into existing plastic production processes.

As mentioned in an IEA paper: “Potential climate benefits in polymer production depend on the amount of CO₂ that can be absorbed in the material, which can be up to 50% of the polymer’s mass. For example, a polymer containing 20% CO₂ by weight shows life cycle CO₂ emissions reductions of 15% relative to the conventional production process.” 

Of course, there are controversies to this: plastics are the very material the world wants to avoid, because it doesn’t degrade well, polluting our seas and environment. Yet, it’s this very fact that helps to lock the carbon away for decades. Plastic isn’t something we can live without – from fundamental living needs to medical applications, it’s a functional, durable, and waterproof material that is nearly impossible to replace.

A system in which used plastics made from carbon are responsibly collected or recycled at the end of their use will help mitigate this concern.

Economic considerations: profitability and society

Is CCUS economically viable? If the carbon is mostly stored in geological locations, most probably not. But if captured carbon can become an abundant, key resource or raw material that supports our living needs – making buildings from concrete incorporated with carbon, food from carbon, or useful plastic goods made from carbon – it would become very practical. As the human population, cities, and needs grow, so do the needs for real estate development, sustenance, and functional products made out of plastic. Wouldn’t it be great to have ‘locked-away’ carbon serving our living needs while staying out of the atmosphere?

For now, the CCUS systems in place are very expensive investments with very low or no returns. This is in part because many haven’t found a practical solution as to what to do with all that captured carbon, or how to lock it in effectively without having it re-released into the environment.

CCUS represents a multifaceted approach to managing carbon emissions. It challenges conventional perceptions of CO₂ and opens doors to innovative uses. Though still a subject of debate and development, CCUS is emerging as an indispensable tool for a sustainable future, offering untapped opportunities for more responsible use of carbon, potentially revealing paths toward both environmental protection and economic benefits.

If we can unlock the potential of captured carbon – making it useful while keeping it out of the atmosphere – the rewards for society, businesses, and mankind could be profound.