I found the below Sankey diagram depicting Romania’s energy flows for 2008 in an article titled ‘A Macro-Micro Perspective on Sustainable Refurbishment of the Housing Sector’ by Ovidiu-Horaţiu Teleche, University of Architecture and Urbanism, Bucharest. Published in Proceedings of 1st International Conference on Architecture & Urban Design, Department of Architecture (2012).

Flows are in ktoe (kilotons of oil-equivalents). Underlying data is from the Romanian National Institute of Statistics and Eurostat 2010. EPP is for ‘Electrical Power Plant’, CHP for ‘Combined Heat & Power Plant’, and DHP for ‘District Heating Plant’.
Note the small flow quantities where arrows are not to scale to be able to view them at all (minimum line width set to 1 or 2 px).

Energy generation is predominantly fossil (coal, petroleum, natural gas). Biomass is the most important energy source in the residential sector. The article doesn’t mention the reason, but my guess is on wood or peat “for preparation of hot water, cooking and direct burning in the stoves for heating” as mentioned in this article on biomass in Romania.

Another quick casual Friday post … again from Austrian company pro-wel, published on their website to market their process engineering services.

Enjoy your weekend!

Interesting blog post by Steve Wexler of Data Revelations. Long article, long title: “Circles, Labels, Colors, Legends, and Sankey Diagrams – Ask These Three Questions”.

The really interesting part for the Sankey diagram aficionados is Steve’s advice on when to use Sankey diagrams, and when you should avoid using them.

Steve illustrates his point with the below example by ‘Music Major – Data Miner’ Jeffrey A. Shaffer (original post is here)

A combination of a stacked bar chart with a distribution diagram, nicely decorated with a trumpet … “Within this context, this very creative chart works”, Steve writes.

He then goes on and shows another one by Shaffer, also a distribution diagram: the original pie chart data from an energy bill has been redesigned and was presented as a distribution diagram (two stacked bars with bands to link them)

In this case, Steve concludes, the choice of a Sankey diagram is maybe not that wise, since the actual important information (44% of energy cost is for heating) doesn’t really come across quickly and clearly. A bar chart might work better here. Sankey diagrams can create a “cool!” or a “crap!” response, depending on the context. See the original Shaffer post here.

Adding my 2c from a technical perspective I would say that both diagrams have a shortcoming: The bands don’t maintain their width as they cross over the others diagonally. Somewhat acceptable in the trumpet diagram as the right bar on the right side listing the music composers is higher than the one at trumpet bell (sound spreading out). Not acceptable in the second diagram where the two stacked bars have the same height. This is obviously an error in the curve radius calculation (read ‘The Math Behind those Curves’)

Austrian technical consulting firm pro-wel offers process engineering services to its customers. Their website features two Sankey diagrams, one of which is a rare circular one with curved arrows (see others).

I also like the technical frame around the diagram, a must have in engineering and architecture.

I liked the below 3-in-1 Sankey diagram from the e!Sankey website. Actually three different Sankey diagrams of the a steam generation process.

The first is a quantitative (mass) view of the process where water, steam, gaseous emissions are shown in kilograms:

Using the same basic structure, the second shows the energy content within the flows. Values are in MJ. Temperature is shown as additional information with a lighter color.

And finally the temperature only Sankey diagram of the steam generation process. Here the width of the arrows shows the temperature of the steam or gas.

In the background is a transparent technical process diagram of the steam process. Thanks to Michael for providing these Sankey diagrams.

Another Sankey diagram of Canada’s energy flows is featured in a blog post titled ‘Dividing the Big Picture: Visualizing Provincial Diversity’. The post appeared May 5, 2014 on the Canadian Energy Systems Analysis Research (CESAR) blog by David B. Layzell, Professor at the University of Calgary. It is a follow up to a previous CESAR blog post that showed “the big picture” for Canada (featured in a recent post here on the blog).

“The Sankey diagram below shows only the domestic portion of Canada’s energy systems. (…) It also shows how much of that demand is met by oil/petroleum (red), natural gas (blue), electricity (yellow), biomass-derived products (green) or other energy resources.”

Flows are in GJ per capita. This relative unit is different to the other national energy flow diagrams I have presented here on the blog. But it is interesting for differentiating energy consumption in the different provinces.

The article explains:

“There are significant inter-provincial differences associated with each end-use category. For example, British Columbia (BC) residents had the lowest residential energy use in the nation, at 63% of the per capita energy use in Alberta (52 GJ/capita), the national leader in this category. The balmy BC climate compared to what Albertans face each winter accounts for most of this difference. However, our model also draws on government data showing that many BC buildings tend to be better insulated than those from much colder Alberta.”

Check out all Sankey diagrams tagged ‘Canada’ here.

Only a few hours left until the kick-off of the FIFA World Cup in Brazil … A reader from Germany recently sent me a clipping from the May edition of Germanwings inflight magazine (read it online here). The article on page 36/37 has this Sankey diagram:

Interesting visualization, though not fully in line with the basic rules for Sankey diagrams. The width of the bands represents the number of times the world cup has been won. The main issue is that only eight of the participating countries have ever won the cup (Brazil, the pentacampeão won it 5 times, so far…). For most of the nations shown, the green stream or arrow thus stands for zero wins. Zero (nil) however is impossible to display in a Sankey diagram, if you want to maintain the basic rule of arrows being proportional in width to the quantity displayed by them.

Several approaches have been proposed for the “zero quantity flows” such as a thin dotted line, or a thin line with a label “no flow”, or a colourless line. In the above case the choice of the diagram type is – in my opinion – not the luckiest one. The main message is that all teams are dreaming of getting to Rio’s Maracanã stadium on July 13.

Also see my two posts for the 2010 world cup here and here with a slightly different Sankey diagram.

Featured on the Canadian Energy Systems Analysis Research (CESAR) blog is the below Sankey diagram on Canada’s Energy Flows in 2010. The article reports about a new model called ‘CanESS’ (Canadian Energy Systems Simulator) developed by Technologies Inc. and the University of Calgary.

Pulling together data from different sources the tool can visualize energy flows as Sankey diagrams.

The big picture of Canadian energy in 2010 is as follows:

“Canadian primary energy production in 2010 was nearly 25,600 PJ, and after including 3,700 PJ of imports, total primary energy availability was 29,500 PJ. As the Sankey diagram shows, 58% was exported, with the remaining 42% or 12,500 PJ being used domestically, 910 PJ for non-energy applications and 11,652 PJ for the provision of energy end use services to Canadians.”

Read the full article by Ralph Torrie on “the big picture” here.

There is an interactive version that allows you to choose the year (1978-2010), to break down the data onto each Canadian province, or change the unit. Try it out!