# Model Documentation

### | Version 4.0

created with goxygen 0.21.1

# 16_demand

# Demand (16_demand)

## Description

The demand module calculates the demand for all commodities that has to be fulfilled by the model. In addition, it returns some other basic information needed for demand calculations but also needed by other modules. A description of food demand scenarios that enter the model can be found in B. L. Bodirsky et al. (2015), B. L. Bodirsky et al. (2012) and Valin et al. (2013).

## Interfaces

Interfaces to other modules

### Input

module inputs (A: sector_may15)
| Description | Unit | A
--- | --- | --- | ---
vm_dem_bioen (i, kall) | Regional bioenergy demand | \(10^6 tDM/yr\) | x
vm_dem_feed (i, kap, kall) | Regional feed demand including byproducts | \(10^6 tDM/yr\) | x
vm_dem_food (i, kall) | Food demand | \(10^6 tDM/yr\) | x
vm_dem_material (i, kall) | Demand for material usage | \(10^6 tDM/yr\) | x
vm_dem_processing (i, kall) | Demand for processing use | \(10^6 tDM/yr\) | x
vm_prod_reg (i, kall) | Regional aggregated production | \(10^6 tDM/yr\) | x
vm_secondary_overproduction (i, kall, kpr) | Overproduction of secondary couple products | \(10^6 tDM/yr\) | x

### Output

module outputs
| Description | Unit
--- | --- | ---
fm_attributes (attributes, kall) | Conversion factors - where X is ton N P K C DM WM or PJ GE | \(X/tDM\)
vm_dem_seed (i, kall) | Demand for seed | \(10^6 tDM/yr\)
vm_supply (i, kall) | Regional demand | \(10^6 tDM/yr\)

## Realizations

### (A) sector_may15

In the sector_may15 realization, demand is calculated as the sum of demand for all products coming from the modules 62_material, 60_bioenergy, 70_livestock, 15_food and 17_production. It also delivers data to the modules 60_bioenergy, 21_trade, 20_processing, 18_residues, 55_awms, 50_nr_soil_budget, 32_forestry, and 53_methane.

Not all demands are relevant for each product group therefore we distinguish into diverse product groups and demand types, according to the equations below. Supply balance for crops, livestock, secondary products and crop residues are calculated as the summation of the corresponding demand for food, feed, processing products, material, bioenergy, seed, waste and the domestic balance flow. Demand for seed, waste and the domestic balance flow are calculated internally within the 16_demand module, while the other relevant demand values are taken from other modules (see interface plot).

\[\begin{multline*} vm\_supply(i2,kcr) = vm\_dem\_food(i2,kcr) + \sum_{kap4} vm\_dem\_feed(i2,kap4,kcr) + vm\_dem\_processing(i2,kcr) + vm\_dem\_material(i2,kcr) + vm\_dem\_bioen(i2,kcr) + vm\_dem\_seed(i2,kcr) + v16\_dem\_waste(i2,kcr) + \sum_{ct} f16\_domestic\_balanceflow(ct,i2,kcr) \end{multline*}\] \[\begin{multline*} vm\_supply(i2,kap) = vm\_dem\_food(i2,kap) + \sum_{kap4} vm\_dem\_feed(i2,kap4,kap) + v16\_dem\_waste(i2,kap) + vm\_dem\_material(i2,kap) + \sum_{ct} f16\_domestic\_balanceflow(ct,i2,kap) \end{multline*}\] \[\begin{multline*} vm\_supply(i2,ksd) = vm\_dem\_food(i2,ksd) + \sum_{kap4} vm\_dem\_feed(i2,kap4,ksd) + vm\_dem\_processing(i2,ksd) + v16\_dem\_waste(i2,ksd) + vm\_dem\_material(i2,ksd) + vm\_dem\_bioen(i2,ksd) + \sum_{ct} f16\_domestic\_balanceflow(ct,i2,ksd) \end{multline*}\] \[\begin{multline*} vm\_supply(i2,kres) = \sum_{kap4} vm\_dem\_feed(i2,kap4,kres) + vm\_dem\_material(i2,kres) + vm\_dem\_bioen(i2,kres) + v16\_dem\_waste(i2,kres) + \sum_{ct} f16\_domestic\_balanceflow(ct,i2,kres) \end{multline*}\]

Supply balance pasture is calculated as the regional feed demand for pasture.

\[\begin{multline*} vm\_supply(i2,"pasture") = \sum_{kap4} vm\_dem\_feed(i2,kap4,"pasture") \end{multline*}\]

Waste demand is calculated as the regional demand of all commodities multiplied by the corresponding waste share and summed up with the overproduction of secondary couple products.

\[\begin{multline*} v16\_dem\_waste(i2,kall) = vm\_supply(i2,kall) \cdot \sum_{ct}f16\_waste\_shr(ct,i2,kall) + \sum_{kpr}vm\_secondary\_overproduction(i2,kall,kpr) \end{multline*}\]

Seed demand is calculated as the regional aggregated production of all commodities multiplied by the corresponding seed share.

\[\begin{multline*} vm\_dem\_seed(i2,kcr) = vm\_prod\_reg(i2,kcr) \cdot \sum_{ct}f16\_seed\_shr(ct,i2,kcr) \end{multline*}\]

> Limitations There are no known limitations.

## Definitions

### Objects

module-internal objects (A: sector_may15)
| Description | Unit | A
--- | --- | --- | ---
f16_domestic_balanceflow (t_all, i, kall) | Balance flow for inconsistencies between domestic supply and use in FAO | \(10^6 tDM/yr\) | x
f16_seed_shr (t_all, i, kcr) | Seed share relative to production from FAO-FBS | \(1\) | x
f16_waste_shr (t_all, i, kall) | Waste share relative to domestic supply from FAO-FBS | \(1\) | x
q16_seed_demand (i, kcr) | Seed demand | \(10^6 tDM/yr\) | x
q16_supply_crops (i, kcr) | Supply balance of crops | \(10^6 tDM/yr\) | x
q16_supply_livestock (i, kap) | Supply balance of livestock | \(10^6 tDM/yr\) | x
q16_supply_pasture (i) | Supply balance of pasture | \(10^6 tDM/yr\) | x
q16_supply_residues (i, kres) | Supply balance of crop residues | \(10^6 tDM/yr\) | x
q16_supply_secondary (i, ksd) | Supply balance of secondary products | \(10^6 tDM/yr\) | x
q16_waste_demand (i, kall) | Waste generation | \(10^6 tDM/yr\) | x
v16_dem_waste (i, kall) | Demand for waste | \(10^6 tDM/yr\) | x

### Sets

sets in use
| description
--- | ---
attributes | Product attributes characterizing a product (such as weight or energy content)
i | World regions
kall | All products in the sectoral version
kap(k) | Animal products
kcr(kve) | Cropping activities
k(kall) | Primary products
kli(kap) | Livestock products
kpr(kall) | Products that can be processed
kres(kall) | Residues
ksd(kall) | Secondary products
kve(k) | Land-use activities
scen42 | Environmental Flow Policy (EFP)
scen_watdem_nonagr | Scenarios for non agricultural water demand
t_all | 5-year time periods
t(t_all) | Simulated time periods
w | Water supply type
wat_dem | Water demand sectors
watdem_ineldo(wat_dem) | Exogenous water demand subset covering humanly induced demands
wat_src | Type of water source

## Authors

Isabelle Weindl, Benjamin Bodirsky, Jan Philipp Dietrich.

## See Also

15_food, 17_production, 18_residues, 20_processing, 21_trade, 32_forestry, 50_nr_soil_budget, 53_methane, 55_awms, 60_bioenergy, 62_material, 70_livestock

## References

Bodirsky, Benjamin Leon, Alexander Popp, Isabelle Weindl, Jan Philipp Dietrich, Susanne Rolinski, Lena Scheiffele, Christoph Schmitz, and Hermann Lotze-Campen. 2012. “N2O Emissions from the Global Agricultural Nitrogen Cycle – Current State and Future Scenarios.” Biogeosciences 9 (10): 4169–97. doi:10.5194/bg-9-4169-2012.

Bodirsky, Benjamin Leon, Susanne Rolinski, Anne Biewald, Isabelle Weindl, Alexander Popp, and Hermann Lotze-Campen. 2015. “Global Food Demand Scenarios for the 21st Century.” PLoS ONE 10 (11): e0139201. doi:10.1371/journal.pone.0139201.

Valin, Hugo, Ronald D. Sands, Dominique van der Mensbrugghe, Gerald C. Nelson, Helal Ahammad, Elodie Blanc, Benjamin Bodirsky, et al. 2013. “The Future of Food Demand: Understanding Differences in Global Economic Models.” Agricultural Economics 45 (1): 51–67. doi:10.1111/agec.12089.