A new web-based Sankey tool, Sankey Flow Show, is available from German software maker THORTEC Software. It promises “attractive flow diagrams made in minutes”.

And indeed the tool is rich in features and design options: Different node elements, shadow effect for arrows (called ‘connections’), toggle constant/Sankey connections style, and customizable data input are some of the highlights.

Here is one of the Sankey diagrams produced with Sankey Flow Show. See more samples here. You can sign-up for a free trial to check it out yourself.


I have added Sankey Flow Show to the list of Sankey software.

Removal of salt from seawater (desalination) is used to produce drinking water and water for irrigation in the Canary Islands, Spain. This is an energy intensive process.

The article ‘La importancia de los sistemas de recuperación de energía en la desalación de aguas en Canarias’ (The importance of energy recovery systems in water desalination in Canary Islands) by Baltasar Peñate Suarez and Sigrid Arenas (both of Departamento de Agua del Instituto Tecnológico de Canarias, ITC) on the IAGUA blog (in Spanish) describes how existing reverse osmosis (RO) salt removal systems with Francis turbines were retrofitted to be more energy efficient.

The two Sankey diagrams in the blog post visualize the energy flows before and after the retrofit. Energy consumption per cubic metre of water desalinated could be reduced from 3.65 kWh/m³ to 3.05 kWh/m³ by installing isobaric energy recovery devices and last generation membranes.

Check out the blog post to see both Sankey diagrams.

Just before the weekend another Sankey diagram for you. One reader suggested I should present a Sankey diagram that contained an Easter egg (without specifying whether he meant flows going in a round, egg-like arrow path or a joke hidden inside the diagram)

Here is one from Japan. It has two loops, and qualifies as a joke too. Just look at the quantities displayed and you know what I mean…

This is from an NTT Technical Review article ‘Development of SOFC Power Generation Module with High Electrical Generation Efficiency’ by Yoshiteru Yoshida, Katsuya Hayashi, and Masayuki Yokoo.

A study on key raw materials and their flows “through the EU economy, as raw materials or as parts of basic materials, components or products” has been produced by BIO Intelligence Service for the European Commission, DG GROW (BIO by Deloitte (2015) Study on Data for a Raw Material System Analysis: Roadmap and Test of the Fully Operational MSA for Raw Materials. Prepared for the European Commission, DG GROW).

It contains Sankey diagrams for 28 materials considered critical or important to European economy, such as cobalt, lithium, or tungsten.

The flows of these materials into the EU-28 geographical area (imports) as well as out of the EU-28 (exports) are displayed for all substances in the same way. Recycling of the substance within Europe is represented as a loop, leading to a kind of see-saw-ish diagram. Additions to in-use (e.g. the substance being part of a product in use) and a certain amount of the substance being disposed off (e.g. as waste) are also shown as arrows to the right. Below is the diagram for cobalt. Flows are in tonnes for the year 2012 (t/y).

All Sankey diagrams are color-coded the same-way, providing additional information whether the material (in the case above: cobalt) is imported as raw material or as part of a product, and whether it is exported as processed material, waste, or also as part of a product.

The study can be downloaded from this page or directly here (PDF, 6 MB)

The energy balance of the German city of Stuttgart has been mapped as a Sankey diagram.

This was part of the project ‘SEE Stuttgart’ (City with Energy Efficiency / “Stadt mit Energie-Effizienz”) and has been developed by Fraunhofer IBP research institute.

A vertical layout was chosen. Absolute energy flow quantities are not shown in this version of the diagram, but are available in the underlying study. In 2010 primary energy consumption in Stuttgart was 20.300 GWh.

The diagram is used to promote a better understanding of the consuming sectors in the city, and the types of energy used. The SEE project aims to reduce Stuttgart’s energy consumption by 20% in 10 years and to transition to non-fossil fuels.

Stuttgart has actually won a first prize in a competition for energy efficient cities in 2016. It is thus setting a benchmark for other German cities. The above Sankey diagram is featured in this promotional video (in German) [at 2:36] and also briefly in this video (in German) [at 0:48] by IBP Fraunhofer.

A high resolution version of the Sankey diagram can be found here.

UK-based consulting firm Green Peninsula has the following Sankey diagram on their website showing electricity generation in the United Kingdom in 2012.


“In 2012 around 920 TWh of primary energy … went into electricity generation in the UK. Due to conversion [in]efficiencies during electricity generation and losses during its transmission, 65% of this energy was lost – primarily as heat. With around 320 TWh reaching the end user, this equates to an overall supply efficiency of around 35%.”

After showing two variants for visualizing the U.S trade balance in my last post, I got aware of yet another option. The first figure (infographic by Spiegel Online) used the length of the arrows to express the value of imported and exported goods. My remake version used the magitude (width) of the arrows, as is typical for Sankey diagrams.

In this figure (by Anthony Cohen, University of Illinois, 2012 / Wikicommons) for US trade in 2011 the arrows for import (red) and export (green) are proportional to the total value of goods, just as we are used to see it in a Sankey diagram. But the arrows are superimposed, with the narrower green export arrow on top of the wider red import arrow. This creates another, somewhat more dramatic impression.

Data shown is for 2011 in billion USD for the 15 most important trade partners. Arrows are not labeled with absolute figures, instead a legend at the bottom indicates the width of five default arrows. The arrow from and to Mexico is a problem (no joke intended!), but the legend clarifies that arrows don’t indicate a specific geographic routing.

When German Chancellor Angela Merkel meets with POTUS today, one topic that’s most likely going to be addressed is the trade deficit between the United States and the EU, Germany in particular.

The Spiegel, a major German news outlet, has illustrated recent articles on this subject with the figure below. It shows the volume of trade between the United States and ‘selected countries’ (China, Canada, Mexico and the EU) in 2015. The values indicate the value of goods exported (green arrows) to these countries, and imported (blue) from them into the U.S. in billion US$.


Source: Spiegel Online

The interesting thing in this infographic is that the length of the arrows represents the value of goods traded. For example, the arrow for exports from the US to Europe (274 bnUS$ in 2015) is little over half the length of the blue incoming arrow (431 bnUS$ in 2015). This works fine, with the only exception being the green arrow for exports to Mexico.

This infographic of course invited a remake as Sankey diagram. As you all know, in Sankey diagrams the widths of the arrows represent the quantity.

I did two or three different versions, all very similar to the original infographic in style and color, even using the lower states map icon (sorry Alaska and Hawaii). I was not sure at first whether the separate arrows for Germany were values already included in the EU trade volume, or if they were meant to be on top of it. A quick look into the original data revealed that indeed they are included in the EU figures already. I therefore decided to highlight the German share in the Sankey diagram with a slightly brighter color, but keep those arrows stacked.

Here is my Sankey diagram version of the Spiegel infographic.

Not sure which version I prefer, but using the length instead the widths of the arrows to represent the flow quantity is definitely a unique approach. Worth sharing with you, I think.