The International Energy Agency (IEA) is a good source for reports on energy, both with a focus on global energy, but also breaking it down to the national level. I have featured their Sankey diagram website that allows to access national energy balances for many countries in this post back in 2013.

Browsing through their reports also sometimes reveals Sankey diagram gems. In their report on ‘Tracking Industrial Energy Efficiency and CO2 Emissions’, however, I found the diagrams on aluminium, steel, pulp/paper and petroleum not particularly sexy.

This is a schematic block diagram. Arrows are labeled with the quantity in Mt/year.

I decided to redo this as a Sankey diagram, maintaining the general structure of the original diagram. The width of the Sankey arrows immediately exhibit where most of the mass (crude oil) is…

I chose three colors: blue for the actual products from petrochemical industry, yellow for recycling streams and losses, purple for the precurors or feedstock (I actually thought I should do away with these, since the ‘hydrogen energy’ flow gave me some headache…). Also decided that the head of the arrow representing 115 Mt/year of post-consumer waste leading towards (!) net additions to stock in the original diagram is erroneous and thus turned the arrow around.

Didn’t spend much time on graphic aspects or fine tuning. I am sure this can be done quite nicely. But even like this I think a Sankey diagram is the better way to get the message across.

This one was sent to me by Winnie Feng (thanks!). A sample visualization of the vinyl chloride process, but with text in Chinese and English.

Polyethylene terephthalate is something everyone of us uses almost every day. Better known by its acronym PET it is used for plastic film and soft drink bottles.

The following Sankey diagram is from a presentation on PET beverage bottle recycling by Brandon Kuczenski and Roland Geyer of Donald Bren School of Environmental Science and Management at the University of California, Santa Barbara. It was held on the First Symposium on Industrial Ecology for Young Professionals (SIEYP) in Tempe, AZ on May 17, 2009.

The Sankey diagram shows PET flows in million metric tons in the U.S. in 2006. 4.29 mio tons of pet flakes are being produced, of which 2.63 mio tons are transformed into PET bottles (other products are PET film and PET fiber). Only 22.4% of these bottles could be recovered after use. This “loss” is being represented by the blue flow which has only a fourth to a fifth of the width of the red entry flow. Recovered PET bottles are exported or reclaimed, closing the loop at least for a fraction of the PET flows.

Interesting Sankey diagram. Congratulations to Kuczenski/Geyer for visualizing this so clearly. Your comments appreciated