I discovered this Sankey diagram in an article by Gutiérrez-Martín, C.; Borrego-Marín, M.M.; Berbel, J. on ‘The Economic Analysis of Water Use in the Water Framework Directive Based on the System of Environmental-Economic Accounting for Water: A Case Study of the Guadalquivir River Basin” (published in Water 2017, 9, 180, open access article licensed under Creative Commons (CC BY 4.0). The Guadalquivir river basin is in Andalusia, Southern Spain.

The authors note that Sankey diagrams for water flows in a river basin or catchment area are useful because they show “at a glance, several aspects of the water cycle such as economic units, abstraction, supply, use, consumption, and returns to environment (soil water not included). In studying water use pathways, Sankey diagrams illustrate quantitative information about flows, their relationships, and their transformations.”

We see water taken (“abstracted”) from surface or groundwater by water supply companies and other users, distribution and water consumption by sectors, water flows ‘lost’ to the atmosphere and return of water to the environment.

Flows in this diagram are in hm³ (cubic hectometres). Note that they decided to use another scale for water used for energy generation (x 10 hm³) since otherwise the yellow-beige would be 10 times wider and maybe spoil the whole diagram.

The diagram has a top-down orientation and numerous loops and flow feedbacks, in contrast to the typical distribution diagrams (aka alluvial diagrams). It is well structured, nicely crafted and pleasing to the eye. Definitely on my top 10 list for 2018.

An interesting Sankey diagram on Global Biomass Flows 2010 can be found on the PBL Netherlands Environmental Assessment Agency website.


(Author: PBL, published under Creative Commons License CC BY 3.0)

This is from a research report ‘Integrated analysis of global biomass flows in search of the sustainable potential for bioenergy production’ published 2014 (available here) that estimates the worldwide biomass flows. It explains: “The biomass flows in the agro complex are presented in ExaJoules in the Sankey diagram (…). Using energy density data for all common commodities, the mass data have been converted to energy data. The energy content depends on the moisture content. In this study, the commonly referred weight–energy ratio’s were used.”

Basically, the diagram is made up from two main strands or pathways for biomass that are interlinked: In the top half the food production from agricultural soils (both crops and livestock breeding). In the lower half the grassland/meadows.

This is exclusively for the agricultural sector. The forestry sector is covered in a separate Sankey diagram (in one of my upcoming posts).

Note that small flow quantities (<3 EJ) are not to scale but rather have a minimum arrow width to keep them visible.

So, after Argentina and Uruguay, here is the Balance Energético Nacional (BEN) for Paraguay.

I couldn’t find any Sankey diagram for the national energy flows on any government website. However, a document on the Balance Energético Nacional (BEN) is published annually by the Viceministério de Minas y Energía. It contains this schematic drawing:

I turned this into a Sankey diagram using the ktep values and the percentage shares indicated.


The structure of this BEN is a little different from the ones previously seen, since it doesn’t indicate the sectors of final consumption. Obviously, most imported crude derivates are used for transport. Regarding biomass, the report indicates that wood is used in households for cooking and sugar cane to produce ethanol to be mixed into fuels for the transport sector. Electricity is produced entirely from hydropower and Paraguay exports over half of the electricity generated to its neighbours Argentina and Brasil.

Uuh-uh, already Friday afternoon… Here is another quick, almost uncommented Sankey diagram, just to not leave you without one for the weekend.

Argentinian environmental consultancy and engineering firm Neoambiental uses this Sankey diagram on its website (go to section 4) to market their professional experience in energy efficiency studies.


Flows are in TJ. Feedstock is crude (brown arrows) and associated gas (yellow). Grey flows are losses or unused energy, while red represents the actual used energy.

I would love to share with you two Sankey diagrams from cement production, but better do respect “Crown Copyright”. These two are featured in Gao, Tianming: Analysis of material flow and consumption in cement production process. Journal of Cleaner Production. DOI 10.1016/j.jclepro.2015.08.054 as figures 7 and 9 on pages 560 and 561. One is for the raw roller mill system, the other from the clinker process. Both Sankey diagrams are for mass flows in the process.

To see the diagrams please go to article on Researchgate.

In lieu of the copyrighted material, please enjoy this schematic of a rotary cement kiln.

Working my way up the southern cone, next in the mini-series on national energy balances for countries in Latin America is the one for Argentina‘s neighbor: Uruguay.

The Ministerio de Industria, Energía y Minería (MIEM) is publishing the Balance Energetico Nacional (BEN) for Uruguay and there is a dedicated website with all the underlying data.


The flow diagram (diagrama de flujo) for the 2015 energy balance was produced by engineering and energy consultancy SEG Ingenieria from Montevideo and appeared in their technical file on energy indicators (Nov 2016, in Spanish only).

Flows are in ktoe (Spanish: ktep, kilo tonelada equivalente de petróleo). The country-wide final consumption in 2015 was 4399 ktoe.

The round icons visualize sources, energy conversion and consuming sectors. They look nice and playful, however, they might also dissimulate the flow quantities: For example, if you look at ‘Transporte’ and ‘Industria’ in the right-hand side, they do have the same diameter, but transport has a 28% share of the final consumption while industry has 42%.

One of the research topics in the research group of Prof. Christos T. Maravelias at University of Wisconsin – Madison is ‘Renewable Chemicals from Lignocellulosic Biomass’. One line of research is into producing chemicals such as 1,4-butanediol (1,4-BDO), 1,5-pentanediol (1,5-PDO) and 1,6-hexanediol (1,6-HDO) from wood chips.

This process Sankey diagram is from the research description page of the Maravelias group.


The red numbers relate to the carbon content in the process (starting with 100% carbon molecules in the feedstock, white birch wood). The coloring of the Sankey arrows is used to signal carbon concentration. And the height of the process nodes shows the cost share of a unit in the process (no absolute cost, just relatively to each other). Interesting! Read more here.

Also see: TriVersa process

Recently I have been reading about energy policies in Latin American countries. Quito-based OLADE, the inter-governmental Organización Latinoamericana de Energía plays a key role in coordination and cooperation between countries in regard to energy.

OLADE has also established the SIER (Sistema de Información Energética Regional), and one of their products is SieLAC (Sistema de Información Energética de Latinoamérica Latina y el Caribe) where energy data for 27 countries can be accessed.

For all countries the national energy balance (Balance Energético Nacional, BEN) can be produced as Sankey diagrams for the years 2005 through to 2010. Further, these energy flows can also be shown for regions, such as the Caribbean, the Andean countries or the “Southern Cone”.

Here is the one for Argentina in 2010.

To try for yourself, just go to the sieLAC page and click on ‘Balance Energético Resumido’. Then select country, year and the unit.
Unfortunately, data for more recent years is not available at this time.

This work of OLADE has inspired me to start a loose mini-series of posts titled ‘LatAm BEN’ where I will be showing Sankey diagrams representing national energy balances from the region. Don’t worry, they will not all be from SieLAC, and will show how differently BENs can look like.