power plant were compared to the reference scenario for which the power produced substitutes production from
a combined-cycle gas plant. The global warming potential was found not to be particularly sensitive to
a switch of substitution from gas to UK average grid mix. The difference was more significant in the
case of the switch to coal power substitution but was not sufficient to change the overall ranking
compared to the other technologies.
An analysis on this parameter was also conducted in study no 3 in which the base case assumes that the heat
produced by incineration or landfill waste replaces heat from forest residues. A sensitivity analysis was conducted
for PET to analyse the effect of a switch to natural gas for heat production. Under this assumption, an avoided
non-renewable fuel consumption is credited to the system. The results showed that the global energy balance is
very slightly affected. For depletion of natural resources, this change induces a change in the ranking between
the alternatives. Incineration appears as a better alternative than landfill in the natural gas scenario while in the
base case landfill performed better. The global warming potential decreased by 60% for the natural gas scenario
but the ranking is not affected, i.e. recycling remains the best option while landfill is still the worst one. For the
acidification impact, the effect is the other way around and landfill becomes a better alternative than incineration.
Table 43 Choice of substituted power in the selected studies by order of importanceStudy n°1 Study n°2 Study n°3 Study n°4 Study n°5 Study n°6 Study n°7 Study n°8
Country electricity mix
susbtituted France UK / Italy Japan USA Australia Germany
Main energy sources
constituting the mix
1NuclearNatural gas Coal Natural gas Nuclear Coal Coal Coal
2 Coal Coal Coal Natural gas Nuclear
3Nuclear Natural gas Nuclear
Source of information for the
identification of the energy
sources constituting the mixIEA Study Study IEA IEA IEA Study StudyChoice of substituted power in the selected studies
(only energy sources representing for than 15% of the country mix are indicated)Sorting process efficiency and “default” disposal option
In the case of recycling and pyrolysis, the pre-treatment process and especially the sorting stage are important
when the input is a mix of plastics because the processes can differ according to the plastic types. For instance, it
has been mentioned that in study no 2, one of the pyrolysis scenarios is only suitable for the polyolefin fraction
while some recycling technologies are specific to PE or PP. In addition, sorting is also necessary to remove
impurities prior to recycling. The scraps from the sorting process are then discarded via a default option that can
differ from one study to another. Table 44 presents the assumptions that have been chosen in the selected
studies for which the information was available regarding the sorting efficiencies and the default disposal option.
Table 44 Overview of the sorting processes efficiencies and “default” disposal options in the selected studies.
Study
number1 6 7 4 5 3 2
33% Incineration with energy recovery40% Incineration with energy recovery10% Outside system boundaries10% Landfill25% for the recycling scenario
5% for the pyrolysis scenario
Incineration with energy recovery46%‐55% for recycling scenarios
49%‐54% for pyrolysis scenarios0% (sorting excluded)85% landfill
15% incineration with energy recovery/
Disposal option
Material percentage retained in
the sorting stage (loss rate)