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.

If you don’t use Sankey diagram software and only have Power Point at hand, this is probably what your national energy flow diagram turns out. 😉


Arrow widths are more or less to scale, which is good. But the overall aspect of this Sankey diagram is unorganized, due to diagonal and overlapping arrows. No flow units given.

Another Figure from OECD/IEA World Energy Outlook 2014 report showing energy exports/imports from/to five African subregions.


Coal measured in million tonnes of oil equivalents (mtoe), oil itself shonw in millions of marrels per day (mb/d). Natural gas measured in “bcm” (anyone?).

Given the different units for the flows I think only arrows of the same color should be compared). So not really a Sankey diagram…

The below Sankey diagram from 1949 depicting world’s energy flows in 1937 is shown in this blog post by Michael Hohmann | LMH Design.


Flows are in TWh.
Michael says: “When I first saw this, I was reminded of seeing an octopus and called it an Octopus Diagram, with the octopus’ head at the input end at left, and the tentacles on the right, in between digesting and distributing everything that the various mouths at the head can gobble up”, asking himself “[w]here does all this Input energy disappear to with so little Output energy ending up as useful for us humans?”.

The Spanish island of Minorca (Spanish: Menorca) is part of the Balearic islands archipelago in the Mediterranean Sea. Less crowded than Mallorca, and more tranquil than party location Ibiza, this island is popular for family holidays.

The Strategic Directorate of Menorca (Directrius Estratègiques de Menorca, DEM) has recently published this Sankey diagram depicting the energy flows of the island in 2013.


(via DEM Twitter)

Flows are in MWh. Primary energy input was 2.72 mio MWh in 2013, of which 1.56 mio MWh were used, while 1.92 mio MWh were losses. (difference was exported). Labels are in Catalan.

The energy visual is different from others that I have shown on this blog before: The island is almost entirely depending on petroleum as energy source. Maritime and air transport consumes a large part, as does the services sector (hotels). Industry sector is a rather small consumer.

You can find a report in Spanish with a similar Sankey diagram here.

The Laboratory of Energy Systems Research at Lithuanian Energy Institute (LEI) works on the country’s energy systems and advises policy makers. Here is their diagram of main fuels and energy flows in Lithuania in 2013. Unit is ktoe.

The article ‘Aprovechamiento de la energía procedente del frenado regenerativo en ferrocarriles metropolitanos’ by Álvaro López López published in the Spanish journal ‘Anales de Mecánica y Electricidad (May/June 2013)’, pp 12-18 has the following Sankey diagram.

No absolute numbers are given here. Still, we understand that from the motion energy during braking of the train a part (green flow) can be recovered and is being used for secondary systems (‘SSAA’) as well as being fed back into the overhead wire (‘cantenaria’).

Not sure though whether this Sankey diagram is a representation of the energy recovery during braking action only, or of the energy flows on a typical train ride.

This Sankey diagram for energy flows in Switzerland 2015 is by Max Blatter of energie-atlas.ch.

Flows are in TJ. The diagram has a consistent color coding: electricity in light blue, oil and derivates in orange, natural gas and biogas in yellow.

Sectors where energy is used are shown at the bottom right with private housholds, industry, services, traffic and agriculture.

Interesting to see that Switzerland’s electricity exports and imports were about equal size in 2015 (blue arrows to/from the top).

A 2007 energy flow Sankey diagram for Switzerland was presented in this post.