This paper reports the emergy-based evaluation (EME) of the ecological performance of four water treatment
plants (WTPs) using three different approaches. The results obtained using the emergy calculation software
SCALE (EME
SCALE
) are compared with those achieved through a conventional emergy evaluation procedure
(EME
CONV
), as well as through the application of the Solar Energy Demand (SED) method. SCALE's results are
based on a detailed representation of the chain of technological processes provided by the lifecycle inventory
database ecoinvent®. They bene
fi
t from a higher level of details in the description of the technological network
ascomparedtotheonescalculatedwith aconventionalEMEand,unliketheSED results,arecomputedaccording
to the emergy algebra rules. The analysis delves into the quantitative comparison of unit emergy values (UEVs)
for individual technospheric inputs provided by each method, demonstrating the added value of SCALE to
enhance reproducibility, accurateness and completeness of an EME. However, SCALE cannot presently include
non-technospheric inputs in emergy accounting, like e.g. human labor and ecosystem services. Moreover,
SCALE is limited by the approach used to build the dataset of UEVs for natural resources. Recommendations
on the scope and accuracy of SCALE-based emergy accounting are suggested for further steps in software
development, as well as preliminary quantitative methods to account for ecosystem services and human labor