Tag: energy

Biomass dominates energy flows in Sri Lanka

Do you know what country uses the top level domain “.lk”? Well, I didn’t know it either, until I came across this fine Sankey diagram of the energy flows of Sri Lanka on the website of the country’s Energy Conservation Fund. This island country (formerly known as Ceylon) has some 20 million inhabitants.

The flows in this Sankey diagram are in ‘kTOE’ (TOE = tons of oil equivalent). It shows that most of Sri Lanka’s energy in 2003 came from domestic biomass, the second largest domestic source is hydro power. Imported sources of energy are crude oil (refined in the -currently- sole Sri Lankan oil refinery), petroleum and a small portion of coal.

On the consumption side the largest energy using sector is domestic/commercial, followed by industry (using biomass generated energy as well) and transportation.

Transmission losses are relatively small compared to the situation in other countries. The energy flow picture of Sri Lanka thus is quite different to those I have previously presented here on this blog, such as for the U.S. or for Scotland.

A Sankey for Energy Generation in the U.S.

Joshua Rosenau over at scienceblogs took up on the energy topic in his ‘Thoughts from Kansas‘ and presents a Sankey diagram for the U.S. energy distribution (The Problem of Energy Generation) from an article in Science (Whitesides and Crabtree: Don’t Forget Long-Term Fundamental Research in Energy, Science 9 February 2007:Vol. 315. no. 5813, 796-798). It shows that more than 55% of the energy produced is lost, mainly in transmission and distribution on the grid (approx 25%) and another 30% in transport-related combustion of petrol [Note to self: do a Sankey diagram comparison for 1911 race car and modern light vehicle].

“…over half of the energy produced for our domestic market goes to waste. Fully two thirds of the energy produced by electrical generation and distribution goes to waste.”

This Sankey diagram shows the energy carriers on the left side, the sectors where energy is consumed (noteworthy: traffic has a larger share than industry) as midpoint groups, and a breakdown to useful and lost energy on the right.

Next stop … Sweden!

My Sankey diagram tour around the Baltic Sea continues. After stops in Estonia and Poland, today it is Sweden.

The diagram below is from the website of the energy provider of the Swedish city Lund.

This diagram is in GWh. It shows the different energy sources used in Lund on the left side, like wind energy (“Vindkraft”, 4 GWh) or geothermal energy (“Geotermisk värme”, 183 GWh). The largest portion (1960 GWh) is electrical energy purchased. The arrows on the right hand side show as what type the energy is being consumed: electricity, heat, cold and gas.

I like this diagram for its ‘blockish style” and the very strict horizontal orientation. The fact that certain flow quantities are branching off to join other arrows is indeed rather difficult to depict. You can see – especially on a b/w printout of the PDF file (on their old website) – that they were struggling with this, but they smoothed it nicely with color gradient effects.

If you take out your pocket calculator (and that’s what I always do!), you will come up with a difference of 244 GWh (“inputs” on the left 3361 GWh, “outputs” on the right 3117 GWh). Might this be attributed to transformation losses?

Sankey – the movie. Or: moving Sankey diagrams

Mark Barrett, director of a UK-based energy consultancy Senco, has developed several energy models.

The SEEScen model (Society, Energy and Environment Scenario model)…

…incorporates 11 energy end uses (motive power, lighting, heating etc.) across 15 sectors. Some of these end uses have physical models; for example, domestic space heating and cooling are estimated with a model of a house which allows the effects of parameters such as insulation and internal temperatures to be examined.

Sankey diagrams for several years have been put together to make a short “film” how energy requirements may change over the years, and what shifts might be expected between different ways of energy generation.

To view this animation click on the image (there are some seconds between the frames, be patient).

To be able to see the details, download the Flash move or the GIF from the SEEScen webpage. Make sure you watch the film in the original size.The website www.senco.co.uk has gone offline (?), go to Mark Barrett’s page instead.

This is a neat idea, and it gives a whole new dimension to Sankey diagrams! On a side note: as far as I am informed, there are only two software tools capable of handling timelines in Sankey diagrams, S.DRAW and SankeyVis.…

Lying with Sankey diagrams (1)

I have decided to present in a loose sequence some diagrams I have found on the web that are obviously wrong. Or -let’s put it in other words- don’t reflect the numbers appropriately. Well, we all know that this happens quite often, and if you plan to do that purposely this book might be of use for you…

So, here is the first sample from an Estonian energy portal page:

I kind of like this Sankey diagram, because it is simple, colorful, and even though I don’t speak Eesti, I more or less get the meaning of it.

However, have a look at the gray flow labeled “Muu auru tarbimine” which supposedly represents 2% of the overall energy. Shouldn’t it be much thinner, compared to the other flows? I think this ‘not-to-scale’ representation is owed to the fact that in a diagram set up with a conventional drawing tool (is it Power Point they used?) would be very hard to draw and the label couldn’t be placed inside. So they decided to make it “small” but at the same time “lying” with this diagram.

It is also quite funky how the purple arrow for “Kaod” has an arrow line pretty much to scale, but the arrow head is much fatter!
Ah well, and the percentage values don’t add up to 100% and the percentage values for the green flows (“Pasöörid” and “Pihustuskuivatamine” – I love that word!) are percentiles of the yellow “Aur” flow in contrast to the other percent indications.

Here is the same Sankey diagram but with the values to scale, automatically created with a Sankey diagram software. I have adjusted the percentiles in accordance with the absolute values given.

Do you have an interesting Sankey diagram to share? Send it to phineas@sankey-diagrams.com

Java applet to explore Sankey energy diagram interactively

Researchers of the “energy flow” project at Weimar’s Bauhaus University have developed a Java applet to explore a Sankey energy diagram interactively.


The accompanying explanation says:

We present a system that allows users to interactively explore complex flow scenarios represented as Sankey diagrams. Our system provides an overview of the flow graph and allows users to zoom in and explore details on demand. The support for quantitative flow tracing across the flow graph as well as representations at different levels of detail facilitate the understanding of complex flow situations.

The energy flow in a city serves as a sample scenario for our system. Different forms of energy are distributed within the city and they are transformed into heat, electricity, or other forms of energy. These processes are visualized and interactively explored. In addition our system can be used as a planning tool for the exploration of future scenarios by interactively manipulating different parameters in the energy flow network.

The Java-based online version (in German) allows the visitor to interactively explore the Sankey diagram. They can zoom in, move the nodes, or call additional data for individual layers.

Energy Losses in Industrial Ceramic Furnace

Here are two Sankey diagrams that show the energy losses in an industrial ceramic furnace. The diagrams are oriented top-down. The labels are in German.

The Sankey diagram in blue shows the energy use in an industrial ceramic furnace. The flows are shown in absolute values and in percentage values.

The second diagram in red is similar to the blue one, but it only show the relative flows in percentiles. Additionally the flows entering the diagram at the top have been separated to show their shares. Other flows (‘Rest’) have been grouped together and the individual contributions are shown on the label.