Reducing the filler content has an influence on all life-cycle energy
parts of printing and writing paper. In this scenario, we have
reduced filler content from 21% to 0%. The biomass energy increases
with 8.4 GJ/t as fillers will be replaced by virgin fibres. The process
energy increases with 6.3 GJ/t since it is more energy intensive
to produce fibres than to produce fillers (see Table 2). However,
since more chemical pulping is needed, also the bio-energy output
increases (9.8 GJ/t). A positive impact (7.1 GJ/t) is also seen on the
end-of-life energy, as fillers do not contribute to energy generation
in MSW incineration and they cannot be recycled for reduced
biomass demand. The overall effect of reducing filler content on
the life-cycle energy of printing and writing paper is a reduced
life-cycle energy use of 2.2 GJ/t.