It does work if you take the "distributed" part seriously. If you've got a giant field of panels then it's just another target for the orcs to take out, but if every single house is feeding in a few kw, which some countries are already doing as a result of which power prices there go negative during the day, the orcs can't take out every single house and shed in the country. "Solar on every structure" means literally that, not just in one or two locations.

And it takes quite a bit to knock out a solar panel, they're designed to resist hail and storm damage (and careless shipping/installers) and will continue to function with reduced efficiency in the presence of quite a bit of damage, you'd need to systematically demolish every single panel in an entire city to take it offline.