Carbon Capture and Utilisation (CCU) technologies are progressively transforming captured carbon into a genuine industrial resource. CO₂ from cement plants, anaerobic digestion units, fermentation processes, biomass, or even direct air capture (DAC) is no longer considered solely a waste stream to be avoided, but rather a feedstock that can be integrated into new value chains.

In this context, Life Cycle Assessment (LCA) naturally emerges as the reference tool for evaluating the environmental benefits of these technologies. 

However, one question is frequently raised by industrial stakeholders: 

Why can two LCAs of the same CCU technology lead to completely different conclusions? 

The answer is simple: the results depend as much on methodological choices as on the technology itself.

A high-performing technology, but what is its actual climate benefit? 

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Capturing one tonne of CO₂ does not automatically mean avoiding one tonne of CO₂ equivalent emissions. 

The environmental impact of a CCU technology depends on a set of assumptions that directly influence the final results: 

• What is the source of the captured CO₂? 
• What energy source is used for the capture and conversion processes? 
• How long does the carbon remain stored? 
• What happens to it at the end of its life? 
• Who can claim the climate benefit associated with carbon capture? 

These questions may sometimes seem secondary. However, they are decisive. 

Depending on the assumptions made, the same technology can appear highly beneficial... or deliver a much more limited climate benefit. 

The challenge is therefore no longer limited to developing innovative processes, but also to evaluating them using a robust, transparent, and consistent methodology.

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1. Not all CO₂ sources are equivalent 

CO₂ can originate from: 

Even though the molecule itself remains identical, its origin fundamentally changes the interpretation of the LCA. 

The impacts associated with carbon capture, the avoided emissions, the reference scenarios, and the energy requirements all vary depending on the source considered. Comparing two technologies using different CO₂ sources without explicitly stating these assumptions can lead to misleading conclusions. 

Beyond differences in energy consumption or capture costs, each source also carries an opportunity cost: using a carbon resource for a given application means forgoing other uses that may be more relevant from an environmental or economic perspective. 

2. Who should be attributed the benefit of carbon capture?

 One of the most complex debates concerns the allocation of climate benefits. 

3. Time matters: carbon storage is not only a question of quantity 

Not all CCU solutions store carbon for the same length of time. 

CO₂ may be re-emitted within a few weeks after capture, remain immobilised for several decades in a construction material, or be stored almost permanently in certain geological applications. 

This temporal dimension raises several questions: 

• should a distinction be made between temporary storage and permanent storage? 
• how should delayed emissions be treated? 
• which assessment time horizon should be used: 20 years, 100 years, or more? 

These choices directly influence the resulting climate outcomes. 

4. End-of-life can completely alter the environmental balance 

The fate of carbon at the end of a product's life is often overlooked. A material containing captured CO₂ may be recycled, reused, incinerated, landfilled, composted, or undergo further carbonation. Each end-of-life scenario results in different emissions and can significantly affect the product's overall environmental performance. A robust LCA should therefore include end-of-life scenarios that accurately reflect the product's intended use and likely disposal pathways. 

5. The LCA approach adopted directly influences the conclusions 

Not all LCAs are designed to answer the same questions. An attributional LCA aims to describe the environmental impacts associated with a product within a given system. A consequential LCA, by contrast, seeks to assess the environmental consequences of a decision or a change in the system. 

In the context of CCU, this methodological choice is particularly significant, as it influences the identification of substituted systems, the avoidance of double counting, and the assessment of the actual environmental benefits delivered by emerging value chains. 

Evolving frameworks 

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Unlike other areas of LCA, there is currently no complete international consensus on the full set of methodological issues related to CCU.

Standardisation efforts and methodological guidelines are advancing rapidly, but several issues remain unresolved: 

• allocation rules between the different stakeholders; 
• the consideration of carbon storage duration; 
• dynamic modelling approaches; 
• carbon flow accounting rules; 
• mass balance methods; 
• substitution scenarios; 
• the risk of double claiming environmental benefits and impacts. 

This rapid evolution explains why continuous scientific and regulatory monitoring has become essential to produce robust and credible LCAs.

Beyond calculation: supporting decision-making and gaining autonomy 

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At WeLOOP, we do not only carry out LCAs. We also support industrial stakeholders in their methodological choices, which are key to the credibility of their results: defining baseline scenarios, allocating environmental benefits and impacts, selecting end-of-life assumptions, analysing competing uses of carbon-based resources, and ensuring compliance with international standards. Our aim is to deliver studies that are not only scientifically robust, but also useful for R&D decision-making, decarbonisation strategies, and discussions with investors, auditors, and public authorities. 

This is why WeLOOP also offers bespoke training courses for R&D, innovation, sustainability, regulatory, and strategy teams.

These training courses can be fully tailored to your industrial context and can be based on your own processes or case studies.

Depending on your needs, they may notably cover: 

• LCA methodologies applied to CCU; 
• different allocation approaches and their implications; 
• the consideration of temporary and permanent storage; 
• mass balance approaches; 
• requirements of the main international standards; 
• critical review of published studies; 
• the development of scenarios tailored to your industry sector. 

The objective is not only to understand existing methods, but to enable your teams to make informed decisions from the earliest stages of project development. 

Beyond environmental assessment, companies are now facing strategic choices: which carbon resource to use? Which valorisation pathway to prioritise? How should environmental benefits and impacts be allocated across the different stakeholders in the value chain? LCA is therefore becoming a genuine decision-support tool, enabling not only the quantification of impacts, but also the steering of investments towards the most relevant solutions. 

Towards a robust assessment of CO₂ capture solutions

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CO₂ capture and utilisation opens up major opportunities for decarbonising many industrial sectors. However, demonstrating their environmental performance requires far more than a simple carbon footprint calculation. The methodological choices made in an LCA can significantly alter the results obtained. Understanding, documenting and justifying these choices is now a key issue for scientific credibility, regulatory compliance and competitiveness. 

In a context where the expectations of investors, public authorities, and customers are becoming increasingly demanding, mastering these methodologies represents a real strategic advantage for companies developing the low-carbon solutions of tomorrow. 

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