Nuclear isn’t the only energy phase-out happening in Germany

[NickB79]

1. Economic stagnation and recession explain a lot of it as well

Germany Cuts Growth Outlook as Recession Peril Mounts:

http://www.bloomberg.com/news/articles/2014-10-14/german-investor-confidence-declines-as-growth-prospects-weaken

German exports plunge in latest sign of slowdown:

http://www.ft.com/cms/s/0/a0314a6e-4f86-11e4-a0a4-00144feab7de.html

Which would explain both the drop in consumer demand over the past 12 years (-22.2% per your source's graphic) and the visible dip in virtually all energy sources, even renewables, in the past two years. It also shows virtually all energy sources dipping precipitously when the financial crisis first threw Germany (and the rest of the world) into economic instability back in 2007-2009. Oddly enough, lignite coal appears to have the least variability, showing almost no decline in TWh output in either 2009 or 2014.