Food losses and food waste has been addressed in a number of scientific research papers in recent years. Peter Alexander et.al. write about ‘Losses, inefficiencies and waste in the global food system’ (In: Agricultural Systems, Volume 153, May 2017, Pages 190-200, doi.org/10.1016/j.agsy.2017.01.014)

The article contains two beautiful Sankey diagrams. The first depicts the global food system in 2011. Flows are shown as dry mass. Flows are not individually labelled with the underling quantity, but rather a scale at the bottom shows 5 representative flow quantities and their corresponding width.


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Crop (yellow) and grassland (green) net primary production (NPP) are shown as sources for the global food system. Losses are branching out as grey arrows. These “inefficiencies” of the system are described in detail in the article. The authors observe that “44% of harvested crops dry matter are lost prior to human consumption” and that “the highest loss rate can be found in livestock production”.

The second Sankey diagram shows a section of the above figure, just the dry matter flows from crop harvest and processing, without any losses. This is interesting because it allows us seeing the share of processed and non-processed food being consumed by humans worldwide, and the the share of crop-based food intake (dark blue) compared to animal-based food intake (red). You could call this the veggie / non-veggie split. Based on dry matter that is.


(under terms of Creative Commons Attribution 4.0 License (CC BY 4.0))

If you want to see the corresponding global food system wet mass, protein and energy Sankey diagrams check out this interesting article. A recommended read for all of us eaters.

An article by Bachmaier, Hans; Effenberger, Mathias and Gronauer, Andreas in German agricultural technology publication ‘Landtechnik’ 65 (2010), no. 3, pp. 208-212 describes how “for ten agricultural biogas plants, a detailed balance of greenhouse gas emissions (GHG) and cumulated energy demand (CED) was calculated”.

Below is the Sankey diagram for plant E that has the “best GHG balance of all ten plants with net savings of 85 g CO2-eq per kWh el. Characteristics are a high share of poultry manure in the input saves energy for crop production; no additional mineral fertilizer needed; credit for surplus digested residue; high level of heat use.”

Biogas plant G has “Regular treatment of animal manure from own livestock; intermediate level of heat use; high methane emissions from CGU; high demand of fossil resources during plant operation (electricity supply from grid, fuel oil).”

Both diagrams feature the GHG emission burdens in CO2-eq per kWh electric energy produced from biogas. Upstream chains for fertilizer, diesel and electricity taken into account too. Displaced GHG emissions nonus in green. It is interesting to see that in this agricultural energy scenario methane (CH4) and nitrous oxide (N2O) are contributing to climate change in the same dimension as carbon dioxide.

I have talked about a cereals Sankey diagram by INRIA Grenoble a couple of weeks ago in this post.

Here are two more Sankey diagrams from the underlying article ‘Etude des flux de céréales à l’echelle locale: Exemples en Rhône-Alpes, en Isère et dans le SCOT de Grenoble’ by J. Courtonne, J. Alapetite, P. Longaretti, D. Dupré.

These are the mass flows for cereals production in France (2007/2008) in Mt (1000 tons)

Here is the same cereals process chain “translated” into a water footprint. Unit is million cubic metres of water consumed.

A very clear structure in both diagrams with three columns: grains production, transformation and final products. Choice of color corresponds to the topic.

A research group from INRIA Grenoble engineering school has set up a website for visualization of environmental data. Sankey diagrams are one available visualization option. The below is a sample provided on the website.

The Sankey diagram shows flows along the cereals production chain in France from the 2007/2008 harvesting campaign. Quantities are in 1000 tonnes.

Different grains are shown on the left: wheat (‘blé’), hard wheat (‘blé dur’), maize, barley (‘orge’) and others. Two large end nodes for unprocessed grain exports and use as animal feed (‘consommation animale’). There are further exports as intermediate and processed products. Only a comparatively small fraction is consumed by humans in France as bread, pasta, biscuits.

Could not detect use as energy crops, it is maybe hidden in the ‘industrial use’ flow. Anyway, an interesting application case for Sankey diagrams.

Back after a short later summer break. From a French educational website talking about agricultural practice and environmental management (‘Pratiques agricoles et gestion de l’environnement’) this small distribution Sankey diagram.

Another one in the Misc (Almost) Uncommented Series…