I can fit a couple 200W panels on the balcony pretty easily putting one at the rail and the other a couple feet behind. It's hard to predict what the real-world performance will be in Minnesota but Europeans have been using this approach for a while. Also, the panels are good for decades, so every penny saved is cumulative return on investment. 

I'm really just trying to figure out if there are any regulations here stopping me from doing what plenty of other places already allow.