This study focused on the effect of increasing pressure on
biomass availability (see also Holmberg and Gustavsson (2007)).11
We have analysed this by applying two different boundary conditions
for surplus biomass. Recycling of paper leads to increased
biomass availability, which can potentially be used for energy generation.
It can, however, be questioned if it is justified to allocate
the surplus biomass to the recycling chain. A similar approach has
been chosen by Dornburg and Faaij (2005) who studied costs and
CO2 emissions of biomass cascading. In our system boundary analysis,
we investigated the impact of: (a) allocating recycling benefits
solely to recovered pulp (e.g. accounting the energy input by feedstock
use only to virgin based pulps) and allocating benefits of
virgin fibres (e.g. negative CO2 emissions due to bio-energy production)
solely to these types and (b) of allocating surplus biomass
to the more efficient chains. Both methods have advantages and
disadvantages and this study has shown, that one should be careful
selecting system boundaries in a system where the virgin and
recycling chains are so dependent. A debate is also ongoing in the
LCA community on the allocation of recycling benefits. Due to the
unique nature of the pulp and paper industry, this debate could
have different impacts than that of other materials (e.g. steel, glass).