SolarSpring offices are located on the north side of Freiburg.
By Train and Bus - From Freiburg Hbf (central station):
Take the tram line #1 in the direction “Landwasser”. Exit at the final tram stop “Landwasser / Moosweier” (about 15 minutes drive). Catch bus Nr.36 (direction Hochdorf St. - Agatha Weg) and get off after 5-6 minutes at "Hochdorf, Weißerlenstrasse". Turn into Hanferstr. and you'll see Hanferstr.28 at your left (2 minutes walk).
Driving map to SolarSpring: here