LOUISE – Low-Cost CO2 Capture by Chemical Looping Combustion of Waste-Derived Fuels

Background, goal and scope

The aim of this project has been to prepare for pre-commercial demonstration of Chemical Looping Combustion (CLC) of solid waste-derived fuels. This is an innovative process for generation of power and heat from waste (waste-to-energy, WtE) providing a concentrated stream of CO₂ that is ready for transport and storage or utilization. In CLC, a dual fluidized bed configuration with an air and a fuel reactor is realized. A metal oxide transports oxygen from the air reactor to the fuel reactor. Combustion of the fuel with this oxygen produces a flue gas stream without N₂, thus, highly concentrated in CO₂ and H₂O, enabling efficient CO₂ separation.

This report documents the environmental life cycle assessment (E-LCA) work performed by NORSUS as part of WP 4 ‘Business case development’ of the project. The E-LCA work has been performed in close cooperation with the other partners in this work package, as the E-LCA modelling requires data for all activities along the vale chain of the system. The E-LCA study has been carried out using life cycle assessment (LCA) methodology and the guidelines provided by Zimmermann, Müller et al. (2018) and von der Assen, Jung et al. (2013). These guidelines are especially important for CCU systems with multiple functions, but also for CCS systems. They state that feedstock CO₂ should be classified as an economic flow, rather than intuitively considering utilized CO₂ as a negative GHG emission.

In this project, the ‘user need’ was to capture CO₂. Hence, a specific amount of captured CO₂ was defined as the Functional Unit (FU).

Conclusions

The LOUISE CLC system seems to compete well with existing CO₂ capture systems with regard to climate change.

For CCS systems and climate change, the following conclusions can be drawn:

• Burdens from ship/pipeline transport of CO₂ and storage are of minor importance.
• Land based transport of CO₂ can affect the results.
• Capture rate is of course an important factor. Still, if the rate is above 95%, the residual emissions are insignificant to the total burdens.

For all other indicators than climate, the environmental burdens increase for CCS systems relative to a reference scenario without capture. This is valid both for the LOUISE and the reference CCS cases.

For CCU systems, the use of energy for producing H₂ for fuel/chemical production plays an important role. The study shows that:

• In today’s energy market, storage of the captured CO₂ and production of conventional fuel/chemicals leads to lower climate burdens than CCU-produced fuel/chemicals.
• As long as renewable (or internal produced) electricity can substitute fossil electricity elsewhere in the grid, the climate performance is better than when using renewable electricity for producing CCU fuels/chemicals.
• The Turkish CCU case, which produces acetic acid, has a relatively high break-even point for when CCS is outperformed. This indicates that achieving an environmentally preferable acetic acid CCU production is easier compared to conventional acetic acid production combined with WtE with CCS. In contrast, obtaining an environmentally preferable CCU methanol production is more challenging compared to conventional methanol production combined with WtE with CCS. 

For CCU fuel/chemical production to outperform CCS combined with conventional fuel/chemical production with regard to climate change, at least one of the following preconditions need to be fulfilled:

• A lock-in situation, where excess electricity cannot be exported or used for anything.
• A decarbonised situation (future), where fossil-based electricity is not used at all, and cannot, hence, be substituted.

These principal conclusions for CCU are robust and in line with results from previous analyses and literature (Modahl and Raadal 2023).