Are we ready for carbon capture (in Luxembourg)?

On 17th February was Luxembourg’s Overshoot Day. What this means: if everyone lived like Luxembourg’s residents, we would need several Earths to meet our annual needs in natural resources.

Moreover, in 2024 global average carbon dioxide (CO₂) concentrations saw their highest level ever recorded. The projections for 2025 indicate an even higher concentration and if this situation continues, it will be increasingly difficult to meet our carbon emission targets.

So we thought it’s a good moment to look at how science and technology can help us live within our environmental limits. Besides many efforts to reduce CO₂ emissions, one complementary technology is CCUS: carbon capture, utilisation and storage. We spoke to Dr. Robin J. White at the Luxembourg Institute of Science and Technology (LIST) and Marianne Viart, in charge of Carbon Capture and Storage (CCS) Development for ArcelorMittal Flat Europe, to learn what CCUS is, how it can help us reduce CO₂ emissions and what the challenges are.

Author: Hanna Siemaszko
Editors: Jean-Paul Bertemes, Michèle Weber (FNR)

What is carbon capture?

Robin White: There are three ways to capture CO₂. First and foremost, you have the natural process – carbon dioxide removal through plants during photosynthesis. They capture CO₂ from the air and convert it with the help of sunlight and water into molecules playing an energy storage or structural role such as carbohydrates or lignin. This happens very selectively and at very low efficiency from a classical engineering perspective.

Then you have two technical processes: on the one hand the point source capture. This targets industrial emissions from power plants, cement factories, steel mills, and similar facilities. It involves capturing CO₂ from waste streams e.g. from steel mill blast furnaces. Point source capture can be applied to older or “legacy” industrial infrastructure that will have to continue operating for some time, until for example they are replaced by electrified processes.

Then there's direct air capture (or DAC), which presents a completely different set of technological and economic challenges. The key difference relates to concentration. Point sources have much higher CO₂ concentrations, which makes capturing at scale somewhat easier. DAC, dealing with much lower, atmospheric CO₂ concentration is (currently) far more challenging to justify economically; though it may be a necessary, albeit complementary, technology to achieve net-zero.

After it has been captured: How can the CO₂ be used?

Robin White: We need carbon in many industries and products.

CO₂ can be a potential chemical feedstock. Since 2016 a company called Covestro has for example operated an industrial-scale plant in Dormagen, Germany, that uses CO₂ to synthesise polymers (polyols) that can be used in the polyurethane foam production for use in mattresses.

Fertilizer is also a classic example – producing urea from CO₂ and ammonia (the Bosch-Meiser process). And in South Africa, for example, they historically captured CO₂ from local synthetic fuel production, which can then be used in fizzy drink production. The former is a huge and important product and market globally. The latter not so important.

What are the challenges of utilisation?

Robin White: From a purely chemical perspective, there are certain thermodynamic and kinetic barriers associated with converting CO₂ into something usable and market compatible.

Marianne Viart: Energy consumption of CO₂ transformation processes is a key issue. And there are economic and regulatory challenges that make it difficult to find a viable business case industrially

So, the last letter in CCUS is the storage: How can the CO2 be stored?

Marianne Viart: Once you have separated or captured the CO₂, it needs to be purified to meet certain quality standards in order to protect infrastructure from corrosion damages. Then it is transported to a permanent storage site and injected deep underground into tight geological formations, such as saline aquifers – basically in a tight porous cavity filled with salted water, or ancient oil and gas reservoirs - so depleted fields - or specific rocks such as basalts.

That is what we call CCS – Carbon Capture and Storage.

What are the challenges of storage?

Marianne Viart: In Europe only few places onshore can geologically store CO₂ and they still need to be developed. Most storage sites under development are offshore (in the Netherlands, in Denmark, in Norway, in the UK) which makes the whole value chain more complex.

The transport of CO₂ from emission points to storage is another challenge and infrastructures have to be developed (such as pipeline networks or CO2-shipping terminals).

For the moment only one project in Europe is able to receive via ship and store industrial CO₂ underground. It is situated in Norway and is called Northern Lights.

How much of the CO₂ emitted can be captured?

Marianne Viart: In the industrial sector, CCS is considered as a complement to other decarbonisation levers that primarily reduce CO₂ production - such as energy efficiency, process improvements or electrification – , where no other economically viable decarbonisation solution is found. In certain industries (such as cement, lime, steel, etc.), reducing carbon compounds are used as chemical reactant, and CO₂ produced by chemical reactions cannot be avoided. As of today, among potential solutions to significantly decarbonise hard-to-abate industries, CCS is foreseen to play a major role.

What are the European goals for CCUS?

Marianne Viart: Studies from the International Energy Agency (IEA) suggest that CCUS would need to account for ca. 8% of total emission reductions by 2050 to meet climate objectives. The IPCC, the International Panel on Climate Change, has also indicated that carbon removals would need to play a significant role, targeting 5 to 10 billion tonnes per year. To put it into perspective, total global CO2 emissions are projected to have reached more than 37 billion tonnes in 2024 (source IEA).

In Europe, the regulation called Net-Zero Industry Act sets an EU-level target of 50 million tonnes per year storage capacity by 2030 – an obligation placed on Oil and Gas producers to develop storage capacities in Europe with the view to lift development of the CCS value chain this way.

Robin White: There is no getting away from the fact that we need carbon. And it would make sense that we should use (some of) this captured CO2 in industrial processes. The chemical industry is a good starting point for this (e.g. consider Carbon Recycling International’s activities).

How much CO2 does Luxembourg emit?

Robin White: The most recent official data at the national level indicates that in 2022 there was ca. 8.2 million tonnes of domestic CO2 emissions. Logically, emissions went down during the pandemic, and that's roughly where the data currently stops. They have most likely risen again to pre-pandemic levels, though there was about a 12% drop from 2021 to 2022.

How much of it can be captured through CCUS in Luxembourg?

When you look at Luxembourg's emissions breakdown, over 60% comes from the transportation sector. This therefore requires deployment of DAC technology to capture tailpipe CO₂. This would leave ca. 3.3 million tonnes of CO₂ (based on publicly available data), to be captured predominantly from point sources. To reduce the emissions, in the transportation sector we would need a fast(er) transition to renewables powered transport and logistics, either via electrification or synthetic fuels.

Whilst electrification is slowly penetrating personal transport, the deployment of DAC and synthetic fuels (to cover heavy logistics and aviation) are some years from being deployed at the necessary scales.

Could we store carbon that was captured in Luxembourg?

Robin White: As far as I know, there are no saline aquifers or geological features in Luxembourg that would enable feasible CO₂ storage. It’s also currently not possible legally. This is all likely to be updated.

Marianne Viart: The development of CO₂ pipeline networks is currently considered in Belgium, Germany and France. If storing locally is not possible, Luxembourg could envision to connect to CO₂ pipeline networks under development in surrounding countries. Such infrastructure does not exist yet and is currently in a dimensioning and planification phase.      

For smaller volumes, transportation by trucks and trains are also considered in Europe where legislation allows it.

Why is now a good moment to discuss CCUS?

Robin White: CCUS has been discussed for a long time already. But a bit more recently there's been an initiative by the Luxembourg Ministry of the Economy and Ministry of the Environment to set-up a Carbon Dioxide Task Force; this reflects a need to accelerate our pathways to achieve National Energy & Climate Plan targets and other national and international measures (e.g. Net Zero Industry Act) are pushing this agenda forward.

How developed is the technology for point source and direct air capture?

Marianne Viart:  Some technologies to separate and purify CO₂ from industrial sources already exist. Current technical challenges may be on the level of performance of the capture (purity of CO₂ stream, reliability of the technology, etc.) that can be achieved while bringing the technology to the needed scale as well as  related cost of capturing impacting the full value chain.

Robin White: DAC is a solution that needs to be developed further and ultimately demonstrated and deployed at scale. On a cost per tonne captured basis, DAC is currently 10 to 15 times more expensive compared to point source capture.

Could subsidies be a good way to boost the sector?

Robin White: Yes. In 2023 European Union gave out ca. 111 billion euros of subsidies for fossil fuels (by energy vector). Whether the political situation favours transferring those subsidies into the renewables, green hydrogen, CCUS etc., remains to be seen.

Can you give examples of companies that work on CCUS in Luxembourg?

Robin White: For DAC, there's a company (RepAir) which has a subsidiary in Luxembourg whose technology could potentially reduce the energy demand and cost per kilogram of CO₂ captured. It's an interesting electrochemical-based process which could be powered by renewables. Beyond capturing, and looking downstream, the involvement of Luxembourgish entities (either as a project partner or investor) in the Norsk e-Fuel project in Norway, namely Paul Wurth S.A./SMS Group, LuxAirport, and CargoLux, demonstrates local interest in the value of CCU (and associated Power-to-Liquid concepts) and in this example in the production of synthetic aviation fuel.

What do you think is the potential of carbon utilisation versus storage?

Robin White: The capture and storage approach is probably going to be more competitive because of thermodynamics and process energy demands; for example if you want to convert CO₂ thermochemically with green hydrogen, there is a significant energy demand to split water into hydrogen and oxygen. Conversely, electrochemical conversion of captured CO₂ may offer scope to access certain chemistries (e.g. polymer precursors) in a more attractive manner.

And with regards to the CO2 taxes in Europe?

Marianne Viart: In Europe, large industries are subject to EU-ETS (Emissions Trading System) for the CO₂ emitted on their production sites.

Under this system, CO₂ that is permanently stored via CCS and CO₂ that is used for CCU would not be treated the same way. CO₂ stored under CCS conditions would be ultimately considered as not being released into the atmosphere, whereas for CCU, it is not automatically the case, as it depends on the usage or the product formed. From a regulatory perspective, for CO₂ processed through CCU to be considered as captured, the carbon must be ‘permanently chemically bound’. For example, producing Synthetic Aviation Fuels (SAF) using CO₂ does not exempt the original CO₂ emitter from EU ETS obligations.  

Anything more the readers should know that we didn't talk about?

Robin White: If the purpose is to be circular or sustainable, at some point we need to change something. We're trying to make small incremental steps, but we're not actually getting anywhere in terms of reducing emissions. To what level CCUS will contribute to an increasingly sector coupled, integrated economy remains to be seen, but it will feature - it just might be called something else like Power-to-Liquids. We will continue to need carbon, but it must come from low-impact, circular sources. Using waste CO₂ from one sector as a resource for another (e.g. via CCUS) helps reduce emissions and transit from a linear to a circular economic model

Marianne Viart: To reach Net Zero objective set for 2050, CCS appears to be unavoidable (source IEA) in addition to other decarbonisation levers. The first step to launch CCS value chains in the EEA is to find economically viable business models backed by planification and support of governments.

I would like to conclude by thanking you for the opportunity of contributing to this article. Public awareness on CCS is indeed a key element for the development of such technology at scale.