Author: phineas

Basque Country Circular Economy 2030

A post on the ‘Low Carbon Future’ blog by IDOM caught my attention as it featured the below Sankey diagram. The post is a summary of an event held back in 2019 on the elaboration of a Circular Economy Strategy for the Basque Country” (“Foro de participación para la elaboración de la Estrategia de Economía Circular del País Vasco 2030”).

The diagram shows mass flows in mega tonnes (Mt) for the year 2016 within the autonomous community in the North of Spain. While the arrows are unicolored, stacked bars on the streams reveal their composition with contributions from metallic minerals, non-metallic minerals, fossil fuels, biomass and others.

Somehow I couldn’t get rid of the feeling that I had seen something similar before. And indeed a similar Sankey diagram for global flows is featured in this post from 2015 and – even more so – one for EU material flows in this followup post from 2018. They seem to have served as a template for the creation of a regional Basque version.

Passive House School Building in Germany

Sankey diagrams from Germany (and in German) can be found abundantly on the web (try a Google image search for ‘Energiefluss Sankey Diagramm’). So, when lagging behind or short of time I sometimes pick one for a Friday afternoon post.

Here is one I found on the web page of ‘BINE Informationsdienst’, a resource portal for energy research and examples from practice. This Sankey diagram produced by Hochschule Magdeburg-Stendal.

This energy flow Sankey diagram is for the first school in Germany built in 2014 according to Passivhaus standard in Halle. Flows are in MWh aggregated over a 12 month period. Energy harvested from solar panels on the school’s roof and a wind turbine were 76.1 MWh, with energy from grid amounting to 76.9 MWh. However, 35.5 MWh could be fed back to the grid (Netz-Einspeisung).

Circular Zinc Flows

While some were indulging in an extended spring cleaning (this year labeled ‘quarantine cleaning’) I decided to take on some of the hard disks sitting on my desk.

These circular zinc flow diagrams from 2011 survived the cleaning and are getting a new life here on the blog. They are more or less two versions of the same diagram, apparently with a Sankey diagram in mind.

The first is a top view and shows zinc flows in the economy (U.S. or world? … sorry, but I don’t have the accompanying text any more). Flows are in millions of tonnes (Mt) in 1996. The second one has the same numbers, but adds a 3D perspective…

Some tricky issues here: The ‘zinc in products’ stream of 8.1 Mt narrows down to zero, as the zinc sits in products, from where it later might be released into the cycle again. This does not help the attempt to draw them in a circle (to associate circularity of zinc flows). As a consequence the streams are not to scale (compare, for example the 0,8 Mt scrap feed flow right next to the 6,6 Mt flow for zinc from mines). The 3D perspective and the shadow effect don’t help in any way here…

Check out some more Sankey diagrams with the tag ‘circular’ and this post on radial Sankey diagrams.

Sankey Diagrams for Expressing Relevance

SaraVaca is a specialist on evaluation and data visualization. She runs the VisualBrains blog (check out the visuals CVs section!).

In a 2016 post she discussed using Sankey diagrams to express “Relevance” in evaluation. Having in mind a quantifiable flow perspective in Sankey diagrams, I was not sure how relevance could be translated. “Relevance in Evaluation is understood as the extent to which the aid activity is suited to the priorities and policies of the target group, recipient and donor”, she explains. So for a Sankey diagram that would mean expressing the “extent” or “suitability” in numbers. Which can of course be done either by assigning weight criteria or doing an ABC analysis.

Here is Sara’s sample:

We can see bands of four different widths. Additionally there is a color-coding for different categories for which the relevance is measured. Interesting approach. In 2017 she followed up with a post on ‘More inclusive (Sankey) diagrams to analyze Relevance’.

Textile Flows in the United States

RRS, a consulting firm with expertise in waste reduction, life cycle management and applied sustainable design has this Sankey diagram on textile streams in the US garment industry.

While the figure doesn’t show any numbers explicitly (which I am sure exist, and were used to set up this schematic Sankey diagram), the idea is to show existing alternative paths for post-consumer textile use. Green flows are recycle, reuse and repurpose, while red streams are to incineration. The largest stream is to landfills. RRS is developing ideas and helping to change the material flows in the textile sector to be more environmentally friendly.

Greenhouse Gas Emissions Mexico 2015

Here is a great Sankey diagram visualizing the greenhouse gas emissions of Mexico in 2015. This graphic comes from the ‘Sexta Comunicación Nacional y Segundo Informe Bienal de Actualización ante la Convención Marco de las Naciones Unidas sobre el Cambio Climático’ published by Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT) and Instituto Nacional de Ecología y Cambio Climático (INECC).

The Mexican national inventory of emissions of gases and composites withe greenhouse effect (Inventario Nacional de Emisiones de Gases y Compuestos de Efecto Invernadero) is compiled by INECC on a regular basis as part of its reporting as a signatory to the United Nations Framework Convention on Climate Change (UNFCCC). The report is here, you can find the graphic on pages 110/111.

On the left side we see the different sectors of the country and their contribution to the emission of the 665 Mt (megatonnes) of GHG gases in 2015. The unit of measure is Mt CO2 equivalents. For each of the sectors this is further broken down to the activities causing the emissions. Further to the right these emissions are split to the individual underlying gases,. We see a large share (75%) caused by carbon dioxide (bióxido de carbono), methane and nitrous oxides. 492 Mt CO2eq were released to the atmosphere, while 173 Mt CO2eq were sequestered (absorbed by plants and soil).

1913 public transport 3D map

Leafing through Brinton’s 1914 book ‘Graphic methods for presenting facts’ I found this example of a 3D map that has elements of a Sankey diagram.

This map (photo taken from an exhibit at a 1913 exhibition) shows passenger numbers on the Frankfurt streetcar lines (back then when trams were still called streetcars!)

Brinton explains that “we have a map presentation in which quantities are represented by building vertically above the various routes laid out on the map … made by strips of wood, alternately black and white, glued carefully above each one of the street-car routes. Each of the strips of wood represents 4,000 passengers carried on the street-car lines in 24 hours” (page 224).

The built up flows showing passenger numbers would, if laid sideways, indeed make a Sankey diagram. Building them up using the third map dimension avoids the issue of dealing with wide Sankey arrows in a dense city center, where passenger numbers are highest.

Brinton’s book, although over 105 years from its publication still makes for a great read (as does his 1939 book on ‘Graphic Presentation’, which is basically a sample book for doing infographics).