Page 94 - Materials Chemistry, Second Edition

78 3 Life Cycle Inventory Analysis

value in the products:

KEA(CED)= KPA + KNA (3.4)
KPA = cumulative process energy demand
KNA = cumulative non-energy demand

KPA encompasses all traded Final Energies (EE) for heat, power, light, and the
generation of other useful electricity valued as primary energy through overall
efficiencies of energy supply.
The cumulative non-energy demand is the sum of the energy content of all
energy carriers employed for non-energy purposes (non-energetic consumption,
NEV) 48) and the inherent energy of working materials (SEI) 49) valued as primary
energy.
The KNA, in the USA is often set equal to the energy content of non-energetically
used energetic resources. 50) This implies an allocation problem because, for
example, wood in many countries is rated as an important energy source; in
the USA, however, it is as such marginalised: it is not part of the feedstock energy
and not included into statistics as a resource. VDI-Guideline 4600 quotes:

KNA = NEV + SEI (3.5)

NEV = non-energetic consumption (of sources of energy)
SEI = inherent energy (of materials used)
Both subgroups are valuated as primary energy. It is differentiated – as in the
USA – between sources of energy (listed as such in the statistics) and inflammable
materials generally not rated as energy source.
In contrast to the US practice, both subgroups are added. To us, this distinction
seems artificial as each inflammable material can become an energy source.
Examples of SEI-materials are starch, cellulose, vegetable and animal fats and oils,
most food, and so on.
For the determination of the primary energy consumption, the final energy
consumption (EEV ) must therefore be complemented by the NEV and the
51)
material-inherent energy content (SEI) content. The evaluation of the primary
energy has to consider the overall efficiency of supply of fuels (g) referring to the
respective energy contribution (for definition see Section 3.2.3.2). Therefore, the
entire CED is the sum of all weighted (i, j and k) partial contributions to the final
energy (EE ) and to the material-bound amounts of energy (NEV and SEI ):
i j k
∑ EEV ∑ NEV j ∑ Σ SEI
KEA(CED)= i + + k k (3.6)
g g g
i i j j k k
48) Nicht Energetischer Verbrauch.
49) Stoffgebundener Energieinhalt.
50) Boguski et al., 1996.
51) Endenergieverbrauch.