This is impressive, but I would guess that this was an especially sunny day. I'd like to see what the average output is.
This is in German, but the only source i could find. It says PV produced 3% of the procuced energy in 2011. It is said the capacity grew about 30% since q4 2011, but the stats seem to be pending.
[BS]
In 2010 604,0 TWh where consumed [1], so that would be 604,0 TWh * 3% / 8760 h = 2 GW as a conservative estimate. But note the stats are all a bit out of date.
[1] https://de.wikipedia.org/wiki/Bedarf_an_elektrischer_Energie...
[/BS]
As the graph says 612 TWh where produced, so 612 TWh * 0.03 / 8760h = 2 GW.