Sankey Diagrams

I was asked what the largest Sankey diagram I have seen so far was? Not sure about this. The Swiss biomass flows diagram I featured in January 2009 would be a candidate, but I think the following one is much larger, both in the actual diagram size, as well as in respect to the number of nodes and arrows.

It was created by the marketing department of RWE AG, one of Germany’s big four electricity providers. It shows the energy flows in Germany for 1995. The image file I have is 2588 x 1062 pixels, so when you click on the image below, you won’t be seeing the full image, but only a thumbnail… (also because I don’t want to get sued by their legal department!)

The clear structuring of the diagram is what might be called “very German”: energy sources are at the left, with non-renewables at the top and renewables at the bottom. The second section shows energy conversion, the third section the energy use sectors. These are further broken down, before the arrow join again to show useful energy and energy losses (a 50:50 relationship). Losses in the conversion phase are shown as arrows that branch out vertically to the bottom. Exports and bunkering, on the other hands, is shown as vertical flow leaving to the top. Color coding is very clear, and flows are labeled with figures on each arrow. The unit is petajoule (PJ)

Even the black background goes well with the bright colours. Here are two close-ups of two sections from this energy flow diagram. Enjoy the beauty…

Blog reader Johan Land submitted the Sankey diagram below. “As I am interested in the energy field I especially was fascinated by the LLNL graph over US energy consumption. I spent the weekend on further enhancing the LLNL graph using a trial version of e!Sankey (and data that I have gathered the last few years). I’m attaching the PNG-file for this graph. Feel free to share it if you like the graph!”

(click image to enlarge)

The typical LLNL graph has been extended by the red section on the left that shows a world energy breakdown. Only the U.S. energy consumption is traced further.
The second extension is the pink section. Here, Johan has broken down the energy use sectors ‘Residential’, ‘Commercial’, ‘Industrial’ and ‘Transportation’ in one or two further steps.

All flows are in TWh, data is from 2005 to 2009. The author used several additional data sources and recompiled the data, so that “figures may differ from Lawrence Livermore Laboratory estimations”. See notes for further information.

Good Sankey diagram, and definitely a great job Johan did here. The only suggestion I have, is to add percentage figures to the regional energy breakdown (red section on the left). Unfortunately, the watermark spoils the overall impression, but this is owed to the fact that he used a free trial version.

Johan also mentioned that he is working on forecasts up to 2050, and an animated GIF “running it over time since 1950 up until 2008″. Hope to be able to show you these here on the blog someday.

Kris commented on my last post, that there is an updated version of the Sankey diagram on energy flows in Austria in 2006 to be found in the Statistical Yearbook Austria 2009 on page 360 (page 6 in this PDF).

I also checked out some other Austrian sites and found one for Austrian Energy Flows 2005 (Energieflussbild Österreich 2005) on the Austrian Energy Agency website. It is a little more colorful, and has more information too.

Flows are in TJ. The diagram is divided into four sections, namely “Aufkommen” (energence?), “Umwandlung” (transformation), “Sonst. Verwendung und Verluste” (other uses and losses), and “Endenergieeinsatz” (final energy use). The color code for the energy types is as follows: oil (pale orange), electric energy (red), coal (dark grey), gas (yellow), renewables (dark green), distance heating (light green), hydro (blue). On the right side useful energy is shown in purple, and losses are displayed as light grey arrows. (Thank you to my friend Leo for the translations…).

Yet another national energy flow Sankey diagram, and indeed a very beautiful one. Hope to see updates of it every year.

Found this Sankey diagram displaying the energy flows in Austria in 2002 on a web page with didactic material from that country.

Unfortunately this copy of the diagram isn’t very large, and I have trouble reading and translating everything. Flows are in petajoule (PJ), source given is Statistics Austria.

On the left are imports, withdrawl from stocks, and domestic production. Losses branch off in black to the top. The diagram differs fundamentally from the ones I have presented for other coutries (such as for New Zealand, the United Kingdom, or the U.S.) in two ways:
First, it doesn’t show the energy use by sectors, but instead a breakdown by energetic end use (985 PJ), non-energetic end use (101 PJ), exports (150 PJ), stock increase (18 PJ), as well as energy use within the energy sector itself (81 PJ).
Second, the colors of the flows are used to differentiate between liquid fossil (dark blue), gaseous fossil (medium grey) and solid fossils (light bluegrey) rather than specific energy carriers. Furthermore biogenic energy flows are shown in medium blue, renewables in very light blue. Converted electric energy is in dark grey.

Found this all pink Sankey diagram on Oliver Seely’s webpage. And since copying is actually encouraged and welcomed, I’ll reproduce this 1970 U.S. energy flow Sankey diagram for all readers of this blog. Happy Easter Holidays!

Motiva is a state owned limited company from Finland offering energy efficiency analysis and energy audit for companies. Motiva also developed audit guidelines and models, and engages in training and authorisation of the energy auditors.

In their energy audit reports, they always include a Sankey diagram in the very first chapter. Here is an example:

Other consulting companies, such as Pöyry (not sure how to pronounce this) haven taken on their approach and are also producing Motiva style Sankey diagrams.

Both Sankey diagrams designed in PowerPoint. Not bad at all, but probably quite a time-consuming task.

A reader of the blog alerted me about a new report that contains Sankey diagrams for the United Kingdom’s 2007 and 2050 energy flows. Thanks, Neil!

The report is about heat demand and CHP (Building a roadmap for heat. 2050 scenarios and heat delivery in the UK) and was prepared by University of Surrey and Imperial College for the Combined Heat and Power Association (CHPA). On p. 18 it has the following Sankey diagram. I have shown a similar diagram for the UK in this post.

Data is from the Digest of UK Energy Statistics. All flows are in millions of tonnes of oil equivalent (MTOE). Primary energy demand in 2007 was 237 MTOE.

The second Sankey diagram presented (on page 23) is a scenario for 2050. It was calculated using the MARKAL model.

One must read all the assumptions made for the model to be able to interpret it, but you can see immediately that the “energy system in 2050 is signifcantly altered under the common assumptions presented in all-electricity scenarios. In particular, final energy consumption in 2050 will be reduced by 46% against 2007 figures under the assumptions used in the CCC 80% CO2 reduction scenario”.

I invite you to read chapters 3.3. and 3.4 of the report to better understand the 2050 Sankey diagram. Note that the overall primary energy demand is significantly lower, but power generation almost doubles compared to the current situation. Losses from oil refineries are omitted in this scenario due to lack of data.

A great Sankey diagram by the research group made up from researchers from ICEPT (Imperial Centre for Energy Policy and Technology) and Centre for Environmental Strategy at the University of Surrey.

An interesting project summary can be found on the energyech.at pages, “a virtual exhibition and information platform” by the Federal Ministry of Traffic, Innovation and Technology (Department for Energy and Environmental Technologies) and the Austrian Energy Agency”. A PV-diesel hybrid energy generation system was installed at mountain refuge “Klagenfurter Hütte” in southern Austria to secure power supply and reduce dependency on diesel fuel, and to bring down energy costs.

The Sankey diagram shows the energy flows over a 30-month test period from July 1993 to December 1995. Out of the 4981 kWh of energy, 2124 kWh were produced by the diesel engine, while 2857 kWh came from the 18 sqm installed PV modules. A storage battery is installed, and the diesel generator can be used to recharge it if there is no sunshine. The overall efficiency of the system was 61% over the testing period, but could be higher after the energy measuring equipment (consuming 499 kWh itself) was removed after the testing period.

The Sankey diagram shows actually measured values in kWh. It has a top-to-bottom orientation. Diesel is on the left side, the photovoltaic system on the right. Losses branch out horizontally. The battery is the blue box labeled “DC-Ges.” in the middle.