credited the system for this function, while two others examined the issue in detail. In the new analysis, only one
study addresses the remaining wood matter with no assessment whatsoever included in the results.
Regarding the energy provision and recovery assumptions, in both studies, the examined LCAs were fully
transparent. In the previous WRAP report not many studies including marginal energy sources were found. In the
present review, in spite of the gradual integration of the marginal concept to life cycle thinking, only one out of
the five studies (study no 2) follows the marginal approach.
3.2.6 Data gaps/further research......................................................................................
Key parameters
Most studies present the electricity mixes used in the LCA for substituted energy but do not mention the mix used
for virgin production. Moreover, most of the other key parameters are not analysed sufficiently. Various
conversion efficiencies, mainly associated with energy recovery processes are seldom stated, resulting in
uncertainties in the overall classification (e.g. comparing a state-of-the-art incinerator to an unengineered
landfill).
Carbon storage/sequestration, as well as the alternative use of wood, are quite new fields and have not been fully
analysed yet. However, their effect on the life cycle impacts is quite substantial. The studies that take any of
these issues into account fail to give specific details and assumptions about modelling of carbon. In the case of
recycling it would be relevant to investigate the effects of paper recycling on wood demand and of the related
consequences on land use. Issues around sustainability of wood supply and the contribution of demand for new
and recycled paper to land use change would also benefit from further research.
Another important aspect that has not been addressed properly by the selected studies is sensitivity analysis.
None of the studies included a section where the most important parameters were tested in terms of their
influence on the results. Therefore, the studies gave no indication of the relative importance of the different
parameters by the studies themselves. The only study that included a sensitivity analysis was study no 3, but the
sensitivity of transport during use phase of the material was tested, which is irrelevant to the end-of-life phase.
Coverage of the various end-of-life alternatives
All selected studies examine the three traditional treatment options for paper. New technologies, such as
pyrolysis, gasification or anaerobic digestion and composting are not investigated. The two latter technologies are
applied mainly on the entire organic part of municipal waste or on more appropriate fractions (food, garden
waste, etc). The exclusion of new technologies can be partly explained by their infancy, which makes the
provision of solid background data for an LCA study more difficult, both in terms of assumptions and data.
Moreover, paper waste has been traditionally been handled by the three major treatment options and it is difficult
to divert waste from such a well established management system.
As already mentioned, a study was located that focuses on the composting of paper (ROU, 2007). The absence of
comparisons among different treatment options was the reason for its exclusion. However, if specific
environmental arguments are required, this study figures as a reliable source of information for composting of
paper, as it compares different compost system configurations.
Environmental indicators
There is a clear preference observed for global warming potential when selecting impact categories. All studies
contain results about the climate change contribution, which does not happen for any other category. Primary
energy demand is also preferred by the LCA teams, while for the rest of the indicators, only one or two results
are presented.
The choice of impact categories is informed by the scope of the study, which is determined by the interest the
commissioner of the study has. Therefore, the relative preference for certain indicators is subjective and does not
reduce in any way the quality of the LCA.