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Page 4 of 17 Stichnothe et al. Carbon Footprints 2026, 5, 11

Figure 1. Life cycle of oil palms and the productive area usually considered, respectively reported by plantation operators (picture were
self-taken).

mesocarp-fibers and shells are used as energy carriers for the CHP plant of the palm oil mill. Currently CHP
plants fulfill two functions, they supply heat and electricity for all on-site operations and also serve as waste
treatment. In this study, it is assumed that the CHP plant provides all heat needed in the oil mill. Palm kernel
mills are modeled separately. The production system is shown in Figure 2 and relevant mass flows in Figure
3.

METHOD - CARBON FOOTPRINT ANALYSIS
This CF study is conducted using OpenLCA v.2.4 and the Ecoinvent database version 3.11,
[34]
[33]
consequential module, which provides extensive datasets on existing materials and processes. The ISO 14040
principles and framework are applied, which comprise four main stages: goal and scope definition, inventory
analysis, impact assessment, and interpretation.

Processing oil palm fruits generates multiple products, and market-based substitution is applied by using a
simplified consequential approach, because the authors argue that the consequential approach is better suited
for multi-output systems because mass and energy balances in product LCAs are maintained and indirect
effects, e.g. indirect land use change (iLUC), can be identified [35-38] . However, different arguments can be used
for identifying the most appropriate replacement of by-products [39,40] and consequently, multifunctionality
modeling affects the results [41,42] Therefore, the consequences of modeling choices need to be investigated.

The products of the oil mill are palm oil, palm kernels and surplus electricity from the residues-fed CHP.
Palm kernels are usually processed in separate mills. The average transport distance is 80 km and the
[43]
resulting products are palm kernel oil (PKO) and palm kernel meal (PKM). It is crucial to define the function
in a specified system, e.g. replacement of ingredient X based on crude protein, gross energy, or….