Reducing subjectivity when performing LCA for recycling systems in the paper industry through a comprehensive evaluation of different allocation methods

The allocation of environmental burdens for products in recycling systems remains a significant challenge within the life cycle assessment (LCA) field with a lack of consensus on which methodology should be applied. The present study compared fourteen allocation methods in a corrugated containerboard made of recycled and virgin fibers base case scenario with the aim to showcase the implications and outcomes when applying each methodology. The total CO_{2 eq.} emissions per fifty recycling cycles were calculated by each method, showing variations ranging from 6.3 % to 17.9 % compared to the base case scenario. However, this range decreased to between 0 % and 12 % when acknowledging fiber losses in the system. Thus, this work highlights the importance of including fiber losses when applying the allocation methodologies. The cut-off method proved to be more accurate for allocating emissions in the system studied due to its simplicity of application and lower deviations from the baseline.