Processing module (20_processing)


The processing module calculates the amount of byproducts that are generated during the processing of raw products, and the demand for those byproducts.
Conversion byproducts are generated by the manufacturing of harvested crops into processed food. Of major importance are press cakes from oil production, molasses and bagasses from sugar refinement and brans from cereal milling. While they are also consumed as food, used for bioenergy production or as fertilizer, their most important usage lies currently in livestock feeding.



Name Description Unit A B
$fm\_trade\_bal\_reduction\_annual(t\,k)$ Trade balance reduction - x
$im\_years(t)$ years between previous and current time step years x
$im\_dem\_food(t,i,k)$ regional food demand mio. ton DM x
$im\_dem\_material(t,i,k)$ regional material demand mio. ton DM x
$im\_attributes\_harvest(attributes,kve)$ attributes of harvested organs: used to calculate the contribution of byproducts to feed t (DM WM Nr P K) or GJ (GE) per ton product x
$vm\_dem\_feed(i,kli,kconvby)$ feed demand from the livestock sector for processing byproducts mio. ton DM x

The last columns of the table indicate the usage in the different realizations (numbered with capital letters)


Name Description Unit
$vm\_dem\_convby\_substitutes(i,kli,kcr)$ demand for substitutes of conversion byproducts (when more crop residues are required than would be produced for crop demand) Mt DM
$vm\_convby\_feed(i,kli,attributes)$ nutrients in conversion byproducts fed to livestock by kli (Mt attributes) Tg (DM,WM,N,P,K) and PJ (GE)

Interface plot

Figure 0: Information exchange among modules


(A) off

In this implementation, no conversion byproducts are considered.

vm\_dem\_convby\_substitutes.fx(i,kli,kcr) = 0\\
vm\_convby\_feed.fx(i,kli,attributes) = 0

This realization does not model feed use of processing byproducts and thus cannot represent additional demand for primary feed commodities in the case that generation of byproducts does not satisfy feed demand (i.e. if demand for animal-based products grows faster than demand for crops).

(B) detailed_AUG13 (default)

In the model, the production of conversion byproducts i20_convby_prod(t,i,faoconvby) distinguishes 8 types (brans, molasses and 6 types of oilcakes). In the initial time step, the production of byproducts is taken from FAOSTAT (2011). For simulated time steps, production of byproducts grows with the demand for food and materials of their belonging crops (im_dem_food(t,i,kcr) + im_dem_material(t,i,kcr)). The underlying simplifying assumption is that the processing is done in the region where the final product is consumed. As the food and material demand is exogenous, this calculation can be made outside the optimization in the preprocessing.

Global conversion byproduct production has to match the supply:

\sum_{i} ic20\_convby\_prod(i,faoconvby)) \geq \sum_{i} v20\_convby\_supply(i,faoconvby))

Trade is calculated analogously to tb_old in 21_trade:

ic20\_convby\_prod(i,faoconvby) \geq \\
( (v20\_convby\_supply(i, faoconvby) + v20\_convby\_excess\_dem(faoconvby) \cdot i20\_convby\_exp\_shr(i,faoconvby) )\\
\cdot ic20\_convby\_trade\_bal\_reduction("tece")$(i20\_convby\_self\_suff(i, faoconvby)>=1) \\
+ v20\_convby\_supply(i,faoconvby) \cdot i20\_convby\_self\_suff(i,faoconvby) \cdot ic20\_convby\_trade\_bal\_reduction("tece")$(i20\_convby\_self\_suff(i,faoconvby)<1) )\\

v20\_convby\_excess\_dem(faoconvby)= \\
\sum_{i}(v20\_convby\_supply(i,faoconvby)) \cdot (1-i20\_convby\_self\_suff(i, faoconvby))$(i20\_convby\_self\_suff(i,faoconvby)<=1))

All generated conversion byproducts (supply) have to be used, either for food, feed, material or waste(convby_use):

\sum_{convby\_use} v20\_convby\_use(i,convby\_use,faoconvby)) = v20\_convby\_supply(i,faoconvby)

Nutrients in total feed are the sum of the nutrients in feed for each livestock product category. The separate calculation has to be maintained in order to estimate manure.

\sum_{faoconvby} v20\_convby\_use(i,"feed",faoconvby) \cdot f20\_attributes\_convby(faoconvby, nutrients) ) = \\
\sum_{kli} vm\_convby\_feed(i, kli, nutrients))

Feed demand for conversion byproducts is estimated based on livestock production and product-specific regional feed baskets (see 70_livestock). Feed demand for nutrients (dry matter, gross energy and proteins/nitrogen) in conversion byproducts can be settled either by conversion byproducts, or by concentrates of at least the same nutritional value. Due to the cost-optimization, the model will only settle the demand with concentrates if not enough byproducts are available. The nutrient contents of conversion byproducts stem from Wirsenius2 (2000) and Roy1 et al. (2006)

vm\_convby\_feed(i, kli, nutrients) + \sum_{kcr} vm\_dem\_convby\_substitutes(i,kli,kcr) \cdot im\_attributes\_harvest(nutrients,kcr)) \geq \\
\sum_{kconvby(faoconvby)} vm\_dem\_feed(i,kli,kconvby) \cdot f20\_attributes\_convby(faoconvby, nutrients))

The demand for conversion byproducts for processing, food and other_util are assumed to remain marginal and are fixed to 1995 values:

v20\_convby\_use.fx(i, "processing", faoconvby) = f20\_convby\_use\_by\_product\_1995(i,faoconvby,"processing") \\
v20\_convby\_use.fx(i, "food", faoconvby) = f20\_convby\_use\_by\_product\_1995(i,faoconvby,"food") \\
v20\_convby\_use.fx(i, "other\_util", faoconvby) = f20\_convby\_use\_by\_product\_1995(i,faoconvby,"other\_util") \\
v20\_convby\_use.lo(i, "waste", faoconvby) = f20\_convby\_use\_by\_product\_1995(i,faoconvby,"waste") \\

Bioenergy crops and cotton cannot be used as substitutes for conversion byproducts:


As material and food demand are currently fixed, the production of byproducts (assumed to occur at the demand region) is calculated exogenously.


Name Description Unit A B
$f20\_attributes\_convby(faoconvby,nutrients)$ Nutrient content of conversion byproducts t nutrient per t DM x
$ic20\_convby\_trade\_bal\_reduction(k)$ Current trade balance reduction - x
$ic20\_convby\_prod(i,faoconvby)$ Current production of conversion byproducts Mt DM x
$i20\_convby\_self\_suff(i,faoconvby)$ Self sufficiency concerning the supply with conversion byproducts - x
$i20\_convby\_exp_shr(i,faoconvby)$ Share of global exports provided by an exporting region - x
$v20\_convby\_supply(i,faoconvby)$ Domestic supply of different conversion byproducts Mt DM x
$v20\_convby\_use(i,convby\_use,faoconvby)$ Use of conversion byproducts and substitutes Mt DM x
$v20\_convby\_excess\_dem(faoconvby)$ Excess demand for conversion byproducts Mt DM x
$faoconvby$ FAO conversion byproducts x
$convby\_use$ different uses of conversion byproducts x
$kconvby$ conversion byproduct types according to feed basket classification x
$faoconvby$ conversion byproduct types according to FAO classification x

The last columns of the table indicate the usage in the different realizations (numbered with capital letters)


Benjamin Bodirsky, Isabelle Weindl

See Also

Overview, 70_livestock, 21_trade


1 [Roy et al. (2006)] Roy, R., Finck, A., Blair, G., and Tandon, H.: Plant nutrition for food security, Ferilizer and plant nutrition bulletin 16, Food and
Agriculture Organization of the United Nations (FAO), 2006.

2 [Wirsenius (2000)] Wirsenius, S.: Human Use of Land and Organic Materials, Ph.D. thesis, Chalmers University of Technology and Göteborg University,
Göteborg, Sweden, 2000.