Sankey Diagrams

U.S. Energy Information Admmoinstration (EIA) now has the 2008 Annual Energy Review (AER) on their website. It contains Sankey diagrams for the nation’s overall energy flows (almost a “classic”) and four additional separate Sankey diagrams for petroleum, natural gas, coal and electricity.

This is the U.S. Energy Flow diagram for 2008

Check the original PDF file with the accompanying footnotes for further details. Overall energy consumption in 2008 was 99 Quadrillion BTUs (preliminary value, slightly down from the 101 Quadrillion BTUs in 2007.

Among the other diagrams in the report, I chose to show the one for coal. 1121 mio. short tons have been consumed in the U.S. in 2008, mainly (1041 mio short tons) for electric power generation. The U.S. is a net coal exporter.

The diagram has a weird sinking downward feeling, caused by the fact that the main left-to-right orientation axis is not maintained. Looking at this it makes me want to shout out: “Hey coal Sankey, cheer up, life isn’t that black…!”

The original full AER report (7.5 MB) can be found here.

The Virginia Center for Coal and Energy Research at Virgina Tech has a website on Virgina Energy Patterns and Trends (VETP).

This summary page on natural gas features a Sankey diagram for natural gas flows in Virginia in 2005.

Flows are in million cubic feet. Note that the division line between dry gas production (88.610 million cubic feet) and interstate imports (1.114.460 million cubic feet) overemphasizes VA’s own production. Also the magnitude of the “consumption” flow and “interstate exports” are not to scale, probably owed to the desire of the designer to be able to split up the consumption arrow into separate arrows. The transportation arrow is exaggerated, and would only be a thin line if to scale.

On the VETP summary page for coal, there is another interesting Sankey, also for 2005.

The second one also has some pecularities: The Sankey arrows for imports (15.764 thousand short tons) and exports (21.288 thousand short tons) of coal are not to scale, neither are the losses/unaccounted coal flows 4.951 thousand short tons.

Reminder to self: If I find the time I’ll do these two diagrams properly and to scale.