Category: Samples

General, Samples

What goes up, must come down!

1 Comment on What goes up, must come down!

For most Sankey diagrams I find when browsing the web, a ‘left-to-right’ or ‘bottom-to-top’ orientation prevails. ‘Top-to-bottom’ is less common, but there are also examples like this one.

A rather untypical shape for a Sankey diagram has been up on the German page of the e!Sankey webpage.

pumped_storage

It shows the energy balance for a pumped storage power plant as a curved shape, with the energy input at the left leg, and the energy that can be recovered (77.3%) at the right one.

Energy is stored “in the form of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost off-peak electric power is used to run the pumps. During periods of high electrical demand, the stored water is released through turbines. Although the losses of the pumping process makes the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest. Pumped storage is the largest-capacity form of grid energy storage now available.” (Wikipedia)

I searched for the original Sankey diagram in the source given (Quaschning 2007) and found this text with the diagram in chapter 6.1.2. That diagram already featured the curvy shape, and has just been reproduced similarly.

quaschning2

The use of the curve layout seems justified here. The author chose it to point out the difference in altitude. The upper basin is at the apex of the curve. Water pumped up from the lower basin requires energy, which can partly be recovered when the water runs down again.

What goes up…

Samples

World and US GHG diagrams from WRI

Last August I reported about a Sankey diagram showing World GHG emissions, published on the website of the World Ressource Institute (WRI). I couldn’t show the diagram due to copyright concerns in that post, but to my delight, Tim Herzog, co-author of the WRI publication and Director of Online Communciations at WRI in a comment to my post granted permission. Thanks, Tim!

So here it is:

wri_ghg_sankey

The diagram shows the activity sectors from which of greenhouse gases (GHGs) originate. The largest portion is from energy generation (including transport), followed by land use change and agriculture. Direct emissions from other industrial processes (other than combustion processes) and waste is comparatively small. The arrows on the right side give a breakdown into the individual gases with carbon dioxide as the main greenhouse gas (77%) followed by methane and N2O.

All data is for 2000 and given in CO2 equivalents with the GWP 100a weighting factors for methane, nitrous oxides, HFCs and PFCs from the IPCC 1996 report. The total quantity is an estimate of 41755 MtCO2 equivalent. Land use change shows negative numbers too, because credits can be given for reforestation (newly planted trees absorbing CO2).

Here is the Sankey diagram from the same report just for the 2003 GHGs in the United States.

wri_ghg_sankey_usa

The overall CO2 equivalents are 6978 Mt in the US in that year, but the portion of GHGs from fuel combustion is higher. CO2 is 85% of the GHGs. For more details on the US GHG Sankey diagram, go to the WRI web page.

Kudos to the makers of these Sankey diagrams. Apart from the rich content they convey, they are also beautiful examples of how elegant Sankey diagrams can be.

Samples

Data Center Electrical Efficiency Sankey

The 2007/2008 White Paper #154 Rev 1 published by APC explains “Electrical Efficiency Measurements for Data Centers”. The author points out that DCIE (Data Center Infrastructure Efficiency), defined as ‘IT Load Power’ divided by ‘Total Data Center Input Power’ is a good metric to analyse data center efficiency.

In fact, as can be seen from the Sankey diagram shown in the paper, the majority of electrical energy consumed in a data center is for cooling, UPS and other supporting infrastructure equipment.

power-flow-diagram

No typical DCIE is given, but the samples shown suggest that it ranges between 30 and 50 %. Several constraints have an impact on the actual DCIE, such as the IT load itself and the outside temperature, and thus should be reported along with the measurement.

A nice idea to present the breakdown on electricity consumption as a Sankey diagram, rather than as a (boring?) pie chart, especially when speaking of “power flows”.

Download the WP #154 from APC’s website.

Samples

Teaching kids energy efficiency

2 Comments on Teaching kids energy efficiency

Mr. Palmer, a UK physics tutor, has many of his physics lectures for General Certificate of Secondary Education (GCSE) online, with notes and illustrations. You can find topics such as “motion”, “heat”, “nuclear radiation”, and even “the origins of the universe”. Very infomative, and well illustrated, even if you are not a high school student.

To attract student’s interest and make them understand efficiency in the “electricity” topic, he asks them to draw a Sankey diagram for their iPod.

ipod_energy_sankey

The three Sankey diagram examples Mr. Palmer shows in his notes use the simple but effective grid paper approach that I have shown in this post.

I have tried to get to the numbers behind the diagram, but even in the tech specs, in the product environmental report for the iPod and on Apples environment website, they don’t give details on how much of the power is used for screen lighting and sound, and how much is lost as heat. So I guess that Mr. Palmer might have made these up, and that the energy efficiency of 31% for the iPod is just an arbitrary number…

Even though I didn’t find the hard facts, I came across some ideas and fancy gadgets for the iPod, that make its use “greener”, even though they do not increase the energy efficiency of the appliance itself:

And of course there are several hints, that help to really reduce energy consumption and make your iPod more energy efficient, such as dimming the display and avoiding to do a skip search on titles.

Samples

Where is the money, honey?

2 Comments on Where is the money, honey?

Nathan at FlowingData – Strength in Numbers presented a Sankey diagram by AP’s Nicolas Rapp and Damiko Morris (originally from this post on Nicolas’ blog). It shows where the $173 billion AIG received from government went to.

aigbailout

I especially like the inverse waterfall arrow endings and how they intersect with the grid of beneficiaries.

Nicolas, who works in Information Graphics for Associated Press, later presented another Sankey diagramm, displaying how the “nearly $12 trillion that was allocated in programs affecting the financial services industry” were used.

govt_3trilliopn-spent

The author says “I spent the day researching and realizing this graphic” (@Nick: how much time was the research, how much the drawing?)

He adds “Fun stuff”, a comment which probably refers to the Sankey graphics part rather than to the content depicted… 🙁

Publications, Samples

Energy Recovery from Process Air

1 Comment on Energy Recovery from Process Air

This article on “Energy Savings in Tissue Production Process: The Case of the Hayat Tissue Mill in Turkey” by A. Isiklar, L. Aydin, D. Mainardi and O. Lopez was published in July 2008 in the TAPPSA Journal (Technical Association of the Pulp and Paper Industry of the Southern Africa). The article describes how energy can be recovered from process air in a tissue plant in Turkey using a cogeneration hood. It features three beautiful Sankey diagrams, one of which is presented here.

energy_recovery_mill_turkey

“The exhaust gases coming from the hood are used for the production of the steam needed to feed the YD and the other auxiliary equipment of the mill (wet strength pulper, hall ventilation). The residual energy in exhaust gases in excess from the boiler are used in order to feed a chiller unit, which in turn runs the air conditioning system of the electrical room”.

This almost symmetric top to bottom oriented diagram shows the energy in MW for a certain production capacity (details not given in the article). It is a section of the other Sankey diagram featured in the article (Fig. 3) showing the whole process including the gas turbines plant, the cogeneration hood and the waste heat boilers (omitting only the absorption chillers). Only the latter shows the reduced heat loss (see light blue arrows labeled “to atmosphere”).

As for me, that’s the kind of curves I love… 😉

Fakes, Samples

Swiss Wood Flows

I received another diagram from Gabor Doka, who already pointed out the Swiss biomass flows Sankey diagrams to me. Gabor seems to have a close eye on publications in the environmental field in Switzerland, and he apparently is an avid follower of this blog. I appreciate.

He writes:

Now a very similar topic (just wood flows in Switzerland) but probably a by-the-book example of how not to do Sankey diagrams. This is from the FOEN magazine “Umwelt” issue 4/2008 (full PDF 8 MB here)

swiss_wood_cropped

Shown are wood flows in Switzerland in million cubic metre. Again only in German though.

Errors that I saw include:
a) flows are slimming, when pointing in a non-vertical direction (“angle-dependent violation of mass conservation”). See e.g. “Stammholz Export” and “Energieholz” which both should be 1.3, but the latter is larger.
b) Addition of imports does not lead to wider flows. The author could not be bothered to deal with small flows, although 0.1 represents a 14 % increase over 0.7, i.e. perceptible.
c) The arrows representing “0.1” are over 2 times too wide, i.e. they visually represent 0.23. Also the arrow representing 0.7 is somewhat larger.

He continues:

What I do like is visual aid of identifying inland consumption (red arrows). Also inputs and outputs add up, which is always a nice thing 😉 However, this seems like a stitched together diagram drawn manually (and probably re-drawn for publication). This is supported by the angled design and observation that in the original paper publication, the main input representing 5.7 Mio m2 is exactly 5.7 cm wide…

Not much more to add from my side. Thanks, Gabor, for this contribution.

Samples

From Russia with Sankey…

1 Comment on From Russia with Sankey…

Using e!Sankey myself, I am also a subscriber to the e!Sankey board, so that I get a toast message every time someone posts over there…

Recently they had a post with a sample Sankey diagram in Russian.

cadmium_flow_russian_800

A short interpretation is difficult for me this time, as I don’t understand Russian. I can detect a copper, zinc and lead flow labeled with element names (Cu, Zn, Pb) and iron. One color is used for all flows. The quantities are in tons.

Anyone can explain more of this Sankey diagram?