My panels are racked on the ground.  Largely because I have to clean off the snow often during the winter.  Sometimes I’ll clean my panels 2x, 3x per day as the weather shifts between snow and sun.

Since my panels are ground mounted I do manage to adjust them seasonally.  I don’t think I’d do that if I had to get on the roof each time I wanted to adjust.

Cleaning panels is generally not required.  Lots of arrays never get washed.  A study in Arizona left panels uncleaned for over a year (more?) and it found almost no loss in power.

There are exceptions to that.  At my previous house the birds liked to perch on the top edge of my panels and I lost power in blackberry season.

If I were building a new house and didn’t have space for ground mounts I think I’d design a roof with a opening skylight/door that gave me access to the panels and, perhaps, some sort of catwalk that allowed me to move along the bottom of the panels.  But at least an easy way to reach outside and push the snow off.

Link : http://www.hertzelectricals.com