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)

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.

The article explains that

“Although the diagrams are of an approximate nature they do serve to identify the relationship that each major energy consuming centre has with each other and also readily identifies the prime energy users to which particular attention should be paid in any conservation effort.

In all three product manufacturing processes heating is by far the largest user of energy, representing some 82-87 percent of the total energy requirement in the manufacture of sawntimber, plywood and particleboard, with drying accounting for approximately 87 percent, 61 percent and 62 percent respectively.”

Use of Sankey diagrams with kind permission of FAO