Haven’t posted much in this mini-series recently … not that there would be a lack of Sankey diagrams that have technical defects or simply misrepresent flow quantities with deliberate arrow widths.

In this Sankey diagram from a website by AEPC the blue arrow is grossly exaggerated and not to scale with the other flows.

Flows are in KWh. Energy inputs (solar, fuel for boiler and pumps) on the left. Uses and losses to the right.

An interesting Sankey diagram of sugar production can be found on p. 23 and p. 24 of the 2002 report ‘Möglichkeiten der Wertschöpfungssteigerung durch Abfallvermeidung (biogener Reststoffe) und Nebenproduktnutzung – Feasibilitystudy’ by Austrian researchers Herbert G. Böchzelt, Niv Graf, Robert W. Habel, Johann Lomsek, Susanne Wagner, Hans Schnitzer (all of Joanneum Research).

Why interesting? Because the diagram wouldn’t fit on one page in the report the authors decided to cut it in two parts. Two streams of the first diagram are continued in detail in the second Sankey diagram shown on the next page.

All flows are in mass percent based on an input of 100% sugar beets (‘Rübenschnitzel’, with -schnitzel apparently meaning ‘chips’). The output of 16 mass-% ‘Presschnitzel’ (pressed beet pulp) and 4.18 mass-% ‘Melasse’ (molasses) is further detailed in the second diagram.

Mind that arrow width is different in the two diagrams, so that they two can not be compared directly. Because water dominates the first diagram, the smaller mass flows of the second diagram would be barely visible, if the two were at the same scale.

In a presentation on “Low CO2 production in European food and beverage industry” the author Christoph Brunner from AEE – Institute for Sustainable Technologies (AEE INTEC) suggests process flow sheets and Sankey diagrams as tools used for energy efficiency analysis.

This Sankey diagram is used as an example for the creation of mass and energy balances and the visualization of the production process.

The diagram is from Austria and thefore in German. From translating some words I understand this is probably for a food/dairy industry. Flows are in MWh, but without a time span. Two steam generators (one run with natural gas, the other with petroleum) supply heat to different processes. The cooking chambers (“Kochkammern”) require most, followed by “Selch” (?) and heating of a “KSPW Tank”. Some heat is recovered from condensate.

Sankey diagrams can help understanding the energy flows of process systems and detect hotspots for optimization.

A beautifully crafted Sankey diagram on wood in Austria can be found in the 2012 article ‘Die Bedeutung von Holz als erneuerbarer Energieträger’ (translation: ‘The importance of wood as a renewable energy source’) by Kasimir Nemestóthy on the waldwissen.net website. These are the wood streams in Austria in 2010.

All streams in solid cubic metre of wood (“Festmeter”, fm). Smaller streams less than 0.1 mio solid cubic metres are not displayed.

Here is how the diagram is structured: on the left the sources of wood with imports, harvesting from forests and other non-forest wood sources. Imports and harvested wood is directed mainly to sawmills (“Sägeindustrie”) and to paper industry. Non-forest wood as well as losses from wood industry (bark, wood chips) are for energetic use.

The dark green arrow is saw round wood with the bordeaux-colored stream representing bark. The brown arrow is industrial round wood of lesser quality, mainly used in paper industry. The light pink and light green arrows represent wood chips and firewood. Along with remains from the saw mills and paper industry it is destined for energetic use.

One minor design flaw at the top (arrow from imports to saw mills) where the green arrow overlaps the orange and red arrow in the curve), but by the untrained Sankey eye this will probably rarely be noticed.

There is a second Sankey diagram in the article that details the energy use, but I will save that one for a separate post.

The following Sankey diagrams are from a report published in 2005 by Austrian Environment Protectionn Agency (UBA). The report is on energy efficient technologies and measures to increase efficiency and features practical examples from industry.

Both Sankey diagrams are from the section on cogeneration (chapter 5, p. 105 and p. 106). The first one shows how natural gas is being used to create 118 GWh electricity and 423.5 GWh steam with an efficiency of 90%.

The second diagram is the breakdown of fuels used in another industrial cogeneration plant. It only features percentage values.

Both sets of data could also be displayed in pie charts, but the Sankey diagrams with directed arrows make an allusion to the output from gas, and to the input feed (in the second diagram).

Even before the 2011 release of the ISO 50001 energy management standard, which lists Sankey diagrams as one tool for energy analysis, companies and consultants have been using them in energy efficiency and energy management projects. Many published examples come from Austria, like this one.

Below is a Sankey diagram example for Austrian company ‘Joh. Pengg AG’ from a 2005 report published by Austrian Federal Ministry for Traffic, Innvation and Technology (bmvt): (H. Bayer: ‘Abwärmenutzung und Einsatz Erneuerbarer Energieträger in einem metallverarbeitenden Betrieb’, Report in German, Sankey diagram on p. 34).

All flows in kWh, total energy consumption for the year 2003 is 45,35 Mio. kWh. The red flows are for electric energy, the yellow ones for energy from natural gas. The middle column has the different equipments that consume energy within the company. Useful energy quantities (“Genutzte Energie”) are shown in orange, while losses are outputs in pink that are visually “collected” and joined again in the last node. Not sure what the light blue part stands for.

A company brochure commemorating ’10 Years of Environmental Management’ at Murau Breweryin Austria features this sparkling green Sankey diagram:

The diagram visualizes gaseous emissions (carbon monoxide, carbon dioxide, oxygen, nitrogen, …) from different equipments (e.g. steam boiler, fermentation tank, flare, …) in 2004. Carbon dioxide emissions are given in absolute values as flow label. All flows in kilograms (Note: nitrogen quantity (‘Stickstoff’) probably erronously labeled ‘Mio kg’ in the legend).

Good job … Prost!

In a presentation given by Jurgen Zettl at the EM2010 conference in Vienna, the author reports about the integrated energy management and reporting at Sandoz’ Kundl site.

Page 22 of the PowerPoint has the following Sankey diagram:

The pic isn’t very clear, and it is difficult to see any detail. The overall energy consumption of the Kundl site comes in from the left (962,5 GWh in 2009). It is broken down to electric energy, energy from fossil fuels and energy from biomass (Note: I was wondering about the latter, but this is explained on page 6 that this is “feed for fermentation, solvents, … “). The streams are further broken down by use area. At the right side the flows join again to visualize useful energy and energy losses.

Good to see that large industries are using Sankey diagrams as an important element of their integrated energy management…