Author: phineas

Waste Water Treatment Plant Sankey

An area of application for Sankey diagrams that has (so far) received little attention here on the blog is waste water treatment. The article ‘Nitrogen Recovery from Wastewater: Possibilities, Competition with Other Resources, and Adaptation Pathways’ by Van der Hoek, J.P.; Duijff, R.; Reinstra, O. In: Sustainability 2018, 10(12), 4605 has two Sankey diagrams that merit being featured here.

The first one visualizes the absolute flows through the process in mio m³ per year (volume streams). Data is from the Amsterdam-West waste water treatment plant (WWTP). The main loop leads water from the clarification stage back to the biological treatment stage.

The second Sankey diagram uses exactly the same process structure, but flows are displayed in tons of nitrogen per year. Most of the nitrogen leaves the system as a gaseous effluent. In contrast to the above, the loop of nitrogen loads is in the reject water from the digester fed back to the primary settling stage.

Anyone in for calculating the concentrations? Read the full article here for details.

Metabolic, Rotterdam Construction Flows

Dutch consulting firm Metabolic have posted a great article ‘Why data visualization is critical to driving sustainable change’ on their blog. It features several examples of Sankey diagrams and argues that good visualization is key to sustainability projects and communication.

This infographic shows material flows (construction materials, demolition waste) in tons and energy in TJ. Flows relate to the construction sector in Rotterdam in the year 2015. This was originally produced by Metabolic for the report ‘Circular Rotterdam’.

The authors say. “This Sankey diagram on Rotterdam’s construction sector serves as a strong example of a data visualization for sustainability. It gives municipal authorities and industry stakeholders a clear idea of where they need to intervene – emissions generated largely in construction, material waste largely in demolition. Potential intervention points are highlighted in red; from reducing dependence on fossil fuels in construction to ensuring buildings are designed for renovation or disassembly rather than demolition.”

State Budget Visualized

Valtionbudjetti.fi is a great website from Finland that has the state budget visualized as Sankey diagram.


Tulot is the income and Menot the expenditure. Flows are in Euros.

This visualization and apparently the website has been made by Helsinki-based Hahmota. Check out the state budget website and enjoy exploring the animated diagrams.

Check out Hahmota’s Twitter feed for more.

Energy Flows Germany 2018

Energy consumption in Germany is tracked by AG Energiebilanzen (Working Group on Energy Inventories) and a Sankey diagram is published annually. This is the latest one for 2018 featured on their website.

And again, it leaves me disappointed… Why does such a prestigious group as AGEB, that has been in the business of producing energy inventories since 1990 and energy flow diagrams at least since 2013, if not longer, produce Sankey diagrams that are not to scale?

Energy Transition in Germany, Study

A great number of Sankey diagrams are coming out of Germany, don’t know why that is…

This one is from a study on the (stalling) progress of the ‘energy transition’ (some prefer to call it ‘energy turnaround’, ‘Energiewende’ in German). German Energy Agency (dena) and University of Cologne (EWI institute) have published an intermediate progress report. On climate change, Angel Merkel’s coalition has set the ambitious goal of reducing Germany’s greenhouse gas (GHG) emissions to 55% of the 1990 emission levels by 2030. One pillar of the energy turnaround is the increased use of renewable energy sources.

The study (PDF here, in German) contains a number of Sankey diagrams like this one:


The overall energy consumption of 605 TWh/year in 2015 hasn’t been reduced until 2018, but there is already a noticeable shift away from coal (black streams) and an increase in renewables. On the path to 2030 nuclear energy is to phased out completely and coal an gas are to be reduced significantly in favor of renewables with the overall consumption down to 590 TWh/year, mainly by means of energy efficiency measures.