Page 167 - Materials Chemistry, Second Edition

SOFTWARE FOR LIFE CYCLE ASSESSMENT 151
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LCA software packages with probably the highest market share on a world-
wide level. Both GaBi and SimaPro have been on the market for more than fif-
teen years. While both have a different "style" in modeling a product system,
and have features that the competitor does not offer, they both have a broad
number of features in common, albeit not all features are available in the basic
(cheapest) license versions.
Prices for both SimaPro and GaBi are in the range of several thousand Euros,
with academic licenses offered at a considerable lower price. An international
network of resellers offers local support for each of the systems.
Picking only one point as a main differentiation, SimaPro calculates a prod-
uct system in a matrix inversion, using thereby a highly efficient algorithm
that allows dealing with thousands of processes in one calculation. GaBi, on
the other hand, uses a sequential calculation algorithm that literally goes from
one process to the other to scale the process according to its input to the overall
LCA system.
In consequence, SimaPro is able to deal with a huge number of unit pro-
cesses in one calculation; the contribution of each modeling step to the end
result is available only after the calculation. The algorithm allows SimaPro
to use only unit processes in a calculation, following up the links of one pro-
cess to another dynamically, during calculation. Due to the dynamic linking,
results always represent the recent database status. Updates of processes in
the database are automatically reflected in the results. Loops in processes
(steel as input into the steel making process for example) do not pose prob-
lems in the calculation.
In GaBi, users manually build a system of connected processes. This usually
takes more time, but since the result is calculated stepwise, users get feedback
on single modeling steps, creating modeled pieces, putting them together like
building blocks (Figure 6.2). Processes can have more than one product, since
they do not need to fit into a matrix. Calculating thousands of processes in one
run can pose problems, with loops in the data, too. Updating the processes
when reusing a once modeled process chain is in the responsibility of the user:
selected processes are constantly linked to the model, and updates in the data
base are not automatically reflected. On the other hand, model results remain
stable even if background data are updated.
The "case" with SimaPro and GaBi is an illustration of the importance of
software for the application of LCA. GaBi process models tend to rely on
aggregated system processes, while SimaPro relies on unit processes; unit
processes in SimaPro must have only one product, which must be an out-
put of the process; even waste treatment processes therefore are modeled
to have an output product "waste treatment service" that is input to the
process creating waste

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There are no official statistics, nor do the companies publish data on their sales.