For incineration, the costs per tonne of residual waste (without
organics) were approximately the same as for the mixed residual
waste including organics, although residual waste generated more
energy per tonne, due to a higher calorific value. This was because
the thermal capacity of the incinerator was met with fewer tonnes
in the case of residual waste (a lower annual usage rate), thereby
leading to higher capital and maintenance costs per tonne of input
waste. A similar effect could be observed for the incineration of
solid residues from the anaerobic digestion of organics – although
containing only little energy, incineration costs per tonne of digestion
residue were lower than for both residual and mixed waste,
because of the fixed costs being distributed between more tonnage
(a higher usage rate). Overall, residual waste incineration was less
costly than mixed waste incineration because of the difference in
input waste amounts per functional unit, i.e. 50,352 tonnes of
mixed waste vs. 39,452 tonnes of residual waste. The capital and
operational costs of the scenarios (83 €/tonne in Scenario 1 and
94.73 €/tonne in Scenario 2, without revenues from energy recovery)
were somewhat higher than the values found by Tsilemou
(2006) (32.1 €/tonne and 15.9 €/tonne, respectively), while the
incineration and downstream costs per tonne of waste (64 €/tonne
in Scenario 1 and 73 €/tonne for Scenario 2, 76 €/tonne and 87 €/
tonne, respectively, including transfers) corresponded well with
examples of Danish incineration gate fees of 65 €/tonne (e.g.
Amager Ressource Center, 2014).