The article ‘Understanding China’s past and future energy demand: An exergy efficiency and decomposition analysis’ by Paul E. Brockway, Julia K. Steinberger, John R. Barrett, and Timothy J. Foxon (all of Sustainability Research Institute, School of Earth and Environment, University of Leeds, UK) appeared in Applied Energy 155:892-903 in October 2015 and features a comparison of China’s energy use in 1971 and 2010. These Sankey diagrams were drawn up to show “the overall flow of exergy to end useful work, and the exergy losses that occur during the various conversion processes”.

China’s energy usage is roughly tenfold in 2010 compared to 40 years ago (37 Mtoe up to 355 Mtoe). Not sure whether both diagrams are setup on the same scale but judging from e.g. the black coal flow (140 Mtoe in 1971, 577 Mtoe in 2010) that is about 4 times wider, I would say they are.

Another interesting detail in these diagrams is that the authors have included food and feed as energy source. This is the first time I see this in a national energy flow map. Given that the energy content of this “fuel” is higher than both combustible renewables and renewables together, it seems justified to include it. The efficiency of turning food and feed energy into muscle work, however, is very low (approx. 3%).

I invite you to read the full article (open access) and to comment on the Sankey diagrams shown in Appendix B.

Interesting Sankey diagram on water use in Qingdao, China in 2011. This is from a presentation titled ‘Urban water security – Water-energy-food nexus’ by Josh Weinberg of Stockholm International Water Institute. Atkins and World Resources Institute (WRI) appear as co-authors.

Unit of flow seems to be million m³ (百万立方米). Water origin is mainly surface water (455 mio m³) and local ground water (367 mio m³), with some additional (146 mio m³) brought in from Yellow River and Yangtze River.

Not sure about the split shown with two green flows, possibly breaking down the water use to urban (city of Qingdao) and province.

The middle part shows consumers: Farming (?) is largest consumer with 311 mio m³ per year, followed by ??? with 230 mio m³, and use in industry with 153 mio m³. Polluted water is shown in black.

Maybe someone who reads Chinese wants to chime in…

In this post on rare earths I have recently featured an alluvial diagram depicting rare earths use from a presentation by T.E.Graedel (Yale). That same presentation also lead me to another article by X. Du & T.E. Graedel titled ‘Uncovering the Global Life Cycles of the Rare Earths Elements’ (open access) that has a number of circular flow diagrams I would call “REE wheels”.

The article describes how quantitative data on rare earths is available for mining and processing, but “very little quantitative information is available concerning the subsequent life cycle stages”. Also, data is mostly available for the overall REE production, but not individually for every single rare earth element. They therefore aim to estimate and approximate the quantities for ten REEs, based on sources from China and Japan.

Here is the REE wheel for Yttrium (element Y) from the article:

The diagram can be read from 7 o’clock to 5 o’clock in a clockwise direction. The processing steps are “Mi” (mining), “S” (separation), “F”(fabrication), “Ma” (manufacturing), “U” (use) and “W” (waste management), thus showing the flow of the rare earth element through the economic cycle.

I did a Sankey diagram version of the above Yttrium REE wheel to have the arrow magnitude representing the quantities. Flows are in Gigagrams (million metric tons) per year.

Due to the fact that the arrows connect horizontally and vertically to the node (and do not run diagonally like in the original) my remake looks less “circular” somehow… in fact it resembles more one of those retro indoor AM/FM loop antennas you would hook to your HiFi. So I am not fully satisfied with the outcome. Would it be better if the nodes were tilted 45°?

What’s nice is that the extraction of ore (17.4 Gg) can be directly compared to the 2.9 Gg Yttrium release to the environment. I switched ore input and tailings output at the mining node to have them side-by-side.

Comments and improvement suggestions welcomed.

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.

Air pollution in Beijing, with orange alerts and high health risks made the news (again) recently.

One measure discussed to reduce pollution levels is to issue a partial ban for cars on the streets. This would certainly reduce some of the pressure, however, I am not quite sure whether this would significantly help improve the situation.

Looking at this 2005 energy flow Sankey diagram for China from World Resources Sim Center, one notices that the largest chunk of energy produced in China is from coal.

The energy from coal consumed in 2005 (purple boxes) was seven times higher than the energy consumed in the transportation sector (1.450 million tonnes of coal equivalent vs 230 million tonnes of coal equivalent, if I interpret this correctly). That is without counting losses that occur both at power stations as well as in vehicle engines.

Of course one might argue that traffic probably has risen enormously since 2005. I checked the latest available data for China (2011) at the International Energy Agency (IEA) website where you can access the national energy flow diagrams for more than 100 countries.

It confirms that both coal and petroleum consumption have risen, but coal is still predominant. Transportation makes up for “only” roughly 200 Mtoe (Millions of tonnes of oil equivalent) out of 1644 Mtoe final consumption, while the significant consumption is in industry and ‘other’ (probably private home heating).

So, even if burning of coal and gasoline has different levels of pollution (e.g. through efficient filtering technolgy), my guess is that the main reason for the smog in China are the coal-fired power plants and industrial furnaces. Reducing vehicle traffic will not lead to reduced coal-burning.

Anyone has data on GHG emissions from different sources in China? (preferably as a Sankey diagram….).

Hop Shing Engineering Co. Ltd, a Hong Kong based firm markets their services using this Sankey diagram (heat recovery, cogeneration)

Always nice to see Sankey diagrams in Chinese.

Phosporus in the natural environment and the food chain has been a topic of several posts on my blog. So it didn’t come as a surprise to find yet another diagram on phoshphorus flows over at Nels’s MFA Diagram blog (one of the blogs I follow closely, see blogroll).

MFA diagrams have their focus on the nodes and the build-up of stocks. Sometimes they get a touch of Sankey diagram with the arrows having different magnitudes. The MFA diagram below is for phosphorous flows in China 2008 (original source: Min Qiao, Yuan-Ming Zheng, Yong-Guan Zhu, 2011. Material flow analysis of phosphorus through food consumption in two megacities in northern China). Values are in tonnes.

(click image to enlarge)

We can detect arrows with three different brush widths (my guess is 1px, 2px and 4 px), each standing for a value range into which the actual flow quantity falls. This may, however, bes somewhat misleading when having a quick glance at the diagram.

I quickly “translated” the above diagram to a Sankey diagram with flow values being actually to scale.

(click image to enlarge)

Here it is quite clear where the major phosphorus flows are located (from food production via urban consumption to sewage treatment plant and solid waste disposal: 2923 out of 5374 tons end up here). The other flows are comparatively small, with the phoshporous flow going directly to the aquatic system worth a mention. Two small flows in the center of the diagram are negligible, they are in fact so tiny in comparison to the major flows that they even don’t show up (or just as a hairline) here.

I have therefore added a minimum width of 1 px for small flows so that the annual 17 tons from urban consumption and the 1.9 tons from rural consumption to the solid waste disposal are at least visible (albeit not to scale with the other flows any more).

(click image to enlarge)

Final phosphorous sinks are solid waste disposal (landfill?) and the aquatic system.

Carl-Johan Skoeld of China-based strategic advisory firm Stenvall Skoeld & Company presented the following Sankey diagram in his recent post on ‘How a 31-year old Shanghai office worker spends his money’.

(Stenvall Skoeld & Company via ChartPorn)

This is a fine sample of a Sankey diagram that merits some more explanation:
In fact, these are two combined Sankey diagrams. The overall sum of 10,000 RMB income breaks down to some 25% taxes, 19% savings and 56% spendings (consumption). The Sankey arrow representing the disposable income is then zoomed to allow for more detail to be seen. Hence the Sankey arrows in the left part of the diagram are not the same scale as the ones on the right. The arrows branching out to the top are considered “necessities”, while the one that go downwards represent “discretionary spendings”. Circles at the end of the arrow show the amount in Chinese currency. As the author points out, “this example is from one of the respondents and not an average of all respondents.”