The great legal change (The weighing of Interests)
Historically, all buildings on a listed street were completely blocked from solar power via the heritage service of Swiss municipalities. Things have radically changed with the repetition of the 2050 strategy which automatically placed “The interest in the supply of renewable energy ahead of other interests of non-national scope”. In summary, for a medium-ranked village hamlet, if you make a strong effort in terms of the integrated aesthetic code (BIPV, full black panels), the commission rules positively in 90% of cases. If it is material "placed on excess thickness on the raw metal rail", the blockage legitimately persists.
How to navigate towards Canton approval? The 3 Rules:
If the residence has been assigned an architectural census note (e.g. the famous cantonal note "note 1 or note 2" Vaud, or equivalent in Geneva):
1. Total Roof Integration (In-Roof) : Your panels must align at the exact height of your ironwork with the panel. No extra thickness.
2. Matte and Full-Black Colorimetry : You will have to prove to the land registry a technical sheet called “Glass Mat” or without glare. The white grids of the silver wiring are prohibited.
3. Homogeneity of the entire pan : Urban monuments refuse an asymmetrical 'patch', they often tolerate better the company which will cover 100% the entire cornice in solar up to the crest of the roof ridge than the simple unpleasant little rectangular slice affixed to a very bare slope.
The Alternative to the Architectural Solar Tile
A Swiss pride is the impressive know-how of the Vaudois from Freesuns, Solaxess (NE) or Megasol to produce material with a thin micro-printed film masking the cells. They are capable of reproducing slate tiles and terracotta brick shades. Both Geneva and French heritage accept applications on a massive scale as long as the visual restitution fools the eye of an expert from ten meters from the path.
Procedure
Forget the famous and simple “Announcement to the cantonal service”. In an ISOS object zone or local classified in the heart of a village, a Building permit issued by cumbersome procedure with public inquiry and full pillar implementation is almost the rule.