Also in this study, the allocation of recycling benefits between
virgin and recovered fibres is found to be a difficult question. In our
study, we tried to compromise on the allocation issue by directly
transferring the benefits of recyclability to the life-cycle of that
grade. This method gives the paper grade not only credits for the
recovered fibre input, but also for the recovered fibres that can be
extracted from it after use. Since biomass energy input for recovered
fibres is assumed to be 0, the life-cycle energy use of paper
products from recovered fibres can become negative. However, this
approach gives better insights in the impact of paper production
during the various phases of its life-cycle.