What happens to yard waste and biowaste in Germany? This Sankey diagram from a 2014 PowerPoint presentation titled ‘Flächendeckender Ausbau der Biotonne in Deutschland’ by Peter Krause and Rüdiger Oetjen-Dehne (u.e.c. Berlin) shows how these flows were distributed.

In 2012 there were 14.5 mio. tonnes of yard waste andd 6.6 mi. tonnes of bio waste (kitchen/food waste) were disposed of in Germany. Much of it was collected and treated or – such as in the case of yard waste – composted (7.8 mio. tonnes).

In addition to the absolute quantities the labels along the Sankey arrows show the average per inhabitant (kg/E, a).

A large potential is still in bio waste (orange-coloured arrow) being disposed of in regular household waste (“Restabfall”). Calls for separate collection of bio waste for energy recovery are being made.

An English-language publication ‘A Practical Guide to Energy Efficiency in Production Processes’ published by the Ministry of Economics, Energy, Transport, Urban and Regional Development of the federal German state Hesse (PDF here) describes a structured approach and methodological toolbox to increase energy efficiency in large manufacturing companies. It also contains practical recommendations.

The below Sankey diagrams are based on data from a pilot implementation (“model project”) at a plastics manufacturer.

This is the Sankey diagram for the energy consumption (electricity and gas) in the existing (baseline) scenario

… and for one of the alternatives assessed in the project:

In this alternative scenario, heat is produced from natural gas rather than from electricity, thus reducing transformation losses. Heat recovery measures are also implemented. Flow values are in MWh per year for a given average production volume.

A second alternative scenario with trigeneration is also evaluated (see pp. 43-45 in the report) and potential cost savings and payback time are discussed.

From a design perspective the Sankey diagrams are quite okay, well structured. Some flaws can be noted in arrow segments that run diagonally, where the width of the arrow is not maintained. Overall energy supply and consumption are not shown in the diagram, but only individual values.

Just a quick one to get started in February.

From a German website ‘Vernunftkraft’ comes the following hand drawn (?) Sankey diagram, depicting losses in wind energy and power-to-gas technology.

Two sets of percentage values are given, apparently for two different scenarios. The second Sankey diagram would have the same layout, but different arrow widths. Here is a 2012 post on wind-to-gas-to-power.

Interesting comparative Sankey diagram on page 16 of the 2012 environmental declaration of Rosenheim Stadtwerke (Rosenheim City Power?).

The city is building or already running a wood gasification plant. Instead of just using the heat from directly burning wood (with 30% energy loss), they decided to work with a wood gas carburetor and use the wood gas to run a gas motor. This is somewhat similar to CHP where heat and electric power can be produced. Overall loss of energy (“Verluste”) in the system is only 23%.

The green box at the bottom displays the avoided fossil GHG emissions per tonne of wood for both technologies.

Flows are in MWh, but only some selected arrows are labeled. Unfortunately the flows are not always to scale: yellow arrow “Wärme” (heat) in figure at top representing 3,15 MWh, but shown as half the width of the blue arrow 4,5 MWh. I reckon the diagram was build manually from rectangles and triangles.

A web page of the federal german ministry for Environment, Climate and Energy in Baden-Wurttemberg informs companies about energy efficiency. Sankey diagrams are described as a useful instrument to detect hotspots for improvement and a tool in the framework of energy efficiency analysis.

Twenty five years ago Sankey diagram were drawn by hand, like this one… Depicted are energy flows in the city of Dresden. No colors, just black-and-white with hatching. neat architect’s lettering.

Found this on a website of Bauhaus University in Weimar titled “Interactive Sankey Diagrams – a planning and information tool”. Authors are Hanfler, Fröhlich, Riehmann.

Found this Energy Flow Diagram for Bavaria (Germany) on the Bavarian Ministry of Economy website.

Flows are in Terajoule (TJ). Flows from top to bottom with different consuming sectors like private houdholds, traffic and industry. Different shades of green… 😉

While I generally welcome the fact that these Sankey diagrams are published for nations, regions or states (as is the case here / more examples can be found here on the blog!), I find that care must be taken to respect the basic principles used for these diagrams.

In that respect the above example looks somewhat quirky to me. The reason for this diagram being spoiled is the fat stream (1.195.019 TJ “Umwandlungsverluste insgesamt” – not sure what that means though) merging into the vertical band from the left, and its counterpart (1.701.846 TJ “Umwandlungseinsatz insgesamt”) branching out to the right at more or less the same height. Are these additional inputs and outputs? But then, why do they cross the main direction of the flow? Not clear to me…

Not a good example. I would have expected better from the state where two of my favourite cars are manufactured.

A brochure on efficient use of energy in manufacturing processes in industry was published in 2004 by Bavarian environment agency (LFU). With its catchy title ‘Protect Climate – Reduce Costs’ (German: ‘Klima schützen – Kosten senken’) the brochure targets at small and medium sized companies and aims to raise conciousness about energy efficiency in different areas of a manufacturing company such as pressurized air, air condition, heating/cooling, lighting and others.

On page 6 this Sankey diagram shows an overview of energy flows in the company…

… and on page 7 a detailed view of a process section (extruder, corrugator, spray bath)

The first diagram is in percent of the total energy consumption, directing the interest to the areas that contribute most to energy consumption, losses (and energy costs) in the company. In the second diagram the unit is kW.

Thanks to the blog reader who sent in the brochure and helped out in translating from German.