Issue 06/2018

From Science & Research
allocation of 30 % and shows land use ranges for PLA capacity
in 2017 from 75,000 hectares down to 38,000 hectares, if another
source of feedstock (sugar cane) would be used.
Summarizing, having single changes in fluctuations and raw
material yield assumptions by each, results in a range between
38,000 and almost 115,000 hectares of land, which is necessary to
produce exactly the same amount of PLA.
Looking at different approaches to feedstock yield and how
it affects land use calculation of recent PLA capacities, there is
a tremendous variation in results to be found. By the means of
feedstock yields, land use ranges from -30 % to +30 % and using
another feedstock source varies results up to -57 % compared to
the base calculation.
Thus, results of land use calculations can range as high as the
amount and range of possible impact factors. This is to be kept in
mind, if not only one but two or more impact factors at the same
time are applied, which will multiply and lead to further increased
ranges. Accumulating all ‘best case’ factors in this scenario would
correspond to a theoretical land use of 25,000 hectares of PLA (-76
% against base calculation).
Now, how do we calculate accurately? Concerning deviations
in results due to differing impact factors and also keeping in
mind, that there is no ‚common sense‘ cut-off-rule for renewable
feedstocks (not even in life cycle assessments), there is still more
work needed on this topic. The shown examples could help to
assess land use of bioplastics in a more realistic approach but as
all data gathered by IfBB is openly accessible, further adaptations
to the calculation of land use can be made individually, if needed.
At this point, it should be mentioned that, despite the negligible
amount of land use, even without a more realistic approach of
calculation, there is no reason for the industry to rest on it. The
pressure on agricultural land in the coming decades due to the
growing world population, the loss and erosion of cultivated land
will increase, and thus bioplastics will not be able to escape
discussion.
But there is a major advantage here: The development of
bioprocessing technology increases the possibility of large-scale
use of alternative renewable raw materials, which can be grown
on barren soils, as well as arising new building blocks and the
decomposition of organic waste streams as the starting point for
the (re-)synthesis of biobased polymers is a foreseeable future.
However, the primary goal for all biobased plastics, as well as
for the plastics industry as a whole, should be to create intelligent
material cycles and to achieve higher recycling rates. If the need
for virgin material was to be reduced effectively, fewer resources
would be needed to keep the plastic circle rolling. Saving raw
materials could also be a way to keep the land use impact of
bioplastics on a low level, when the emerging trend steadies or
increases in the near future, to produce larger quantities of usually
petro-based plastics from now available biobased building blocks
(drop-ins).
More information can be found in IfBB’s annualy updated
publication of Biopolymers. Facts and statistics. It can be
downloaded for free at: bit.ly/factsandstatistics
www.ifbb-hannover.de
Table 1
Material group Producer To tal annual
capacity
[t]
Calculations
PLA
A
B
C
Land use
factor
[ha / t]
Multiplication
Equals
To tal annual
land use
[ha]
240,000 0.368 88,300
Figure 2
Sample process route
select desired feedstock/crop, i.e.
sugar cane or sugar beet
land use for 1 t of
resulting polymer
feedstock/crop
0.09 ha
1 387 m³
Sugar
cane
6.62 t
or
0.09 ha
711 m³
Sugar
beet
5.37 t
water usage for
feedstock/crop amount
raw material
Sugar
0.86 t
(chemical) process
process inputs
H2O
Microorg.
Fermentation
CO2
Filtration
H2O
Microbial
mass
intermediate product
resource has
petro-based origin
1,4-BDO
0.52 t
Succinic
acid *
0.69 t
Esterification
Polycondensation
H2O
0.10 t
H2O
0.10 t
process outputs
PBS
bb SCA
1.00 t
resulting polymer
44 bioplastics MAGAZINE [06/18] Vol. 13