Delving into low-cost decarbonisation

The urgent need to decarbonise is a far more acute challenge for cement than most industries. Efficiencies, low-carbon substitutes, and cleaner input fuels will only achieve so much. Cement is a ‘hard-to-abate’ industry because most of its direct emissions are process emissions – CO₂ is unavoidably released from the raw material when heated. For these process emissions, carbon capture is essentially the only viable decarbonisation option.

Even accounting for other potential carbon emissions reductions, the GCCA expects that 1.4 billion t of CO₂ will need to be captured and stored annually by 2050 for the industry to fulfil its commitments and reach net zero. Cement, however, is also a unique, low-cost, and accessible material that provides the foundations of modern society. Decarbonisation solutions must balance environmental goals with social and economic considerations in a just transition to net zero. It is this challenge that Leilac exists to help solve.

The technology

Leilac’s technology was developed for, and in partnership with, the cement and lime industries. It uses calciner tubes to deliver radiative heat to limestone or cement meal. This unique approach simply separates the reaction products from exhaust gases and air, enabling process emissions to be efficiently captured as high purity CO₂. This innovation marks a step change from other carbon capture solutions that require energy intensive processes and additional chemicals or solvents to separate gases from gases.

Low-cost and future-proof pathways to net zero

‘Decarbonising cement: Leilac at full commercial scale’, a new study produced by the Leilac-2 consortium for the European Union (EU), provides a detailed analysis of the Leilac technology’s potential to deliver flexible and low-cost decarbonisation solutions for a cement plant with a capacity of 1.2 million tpy of clinker, with costs based on central European prices.

The study includes a techno-economic analysis of multiple integration options, the use of alternative fuels, biomass, electrification, and Leilac’s technology used in combination with a post-combustion capture unit for emissions from carbon-based fuels.

Low-cost capture of unavoidable emissions

Through a simple replication of the module being developed for the Leilac-2 demonstration plant, the study found that a typical full-scale Leilac plant could capture around 600 000 t of CO₂ a year for a cost of ~€33/t of CO₂ avoided, or ~€16/t of clinker. With transport and storage costs in the range of €15/t of CO₂, full CCS avoidance costs may be possible for around €48/t of CO₂ avoided. Leilac’s cost of capture includes CO₂ compression, maintenance, capital repayment, and results in avoidance of ~75% of the host plant’s fossil CO₂ emissions.

Currently, the cost of emitting CO₂ within the EU is around €90 under the EU ETS, while in the US, the Inflation Reduction Act increased the incentive to capture CO₂ from industry to US$85/t. Full-scale implementation of the Leilac technology at a typical cement plant in central Europe could capture CO₂ emissions worth €53 million per year for an annual cost of €20 million, excluding CO₂ transport and storage.

Unlocking low-cost net zero cement

If a carbon-emitting fuel is used, the Leilac technology can be combined with any other carbon capture process to address fuel emissions. In this case, the addition of a post-combustion capture (PCC) unit can increase CO₂ avoidance rates and deliver carbon neutral or even carbon negative cement. The combined use of the Leilac technology – to capture the unavoidable process emissions – and any viable ‘flue gas capture’ process can also enable significant synergies.

With Leilac capturing the process emissions, the required PCC unit is only one-quarter of the size that would otherwise be required if it were the only technology used for carbon capture. Importantly, this hybrid capture scenario means that the energy requirements of the small PCC unit could be sourced predominantly from waste heat, all but eliminating its largest operating cost.

Using a formulated amine as an illustrative example PCC technology, the techno-economic analysis found that a combined Leilac + PCC system could reach net zero for ~€39/t of CO₂ avoided (excluding transport and storage). A comparative scenario using the same post-combustion capture technology for all plant emissions resulted in a 90% cost increase compared with a dual Leilac and post-combustion capture approach.

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Read the article online at: https://www.worldcement.com/europe-cis/30112023/delving-into-low-cost-decarbonisation/