Photo-voltaic with battery back-up might (or might not) serve all requiremeents.

Our basic reason for the genny was to power DW's medical equipment. Although the equipment has limited battery backup, it is for short term (minutes to a couple of hours outtage). We have 1 to 2 day storm caused outtages here frequently. Once, for 7 days. We need the genny for 24 hour/7 day a week coverage if (or rather when) we lose power. And some of the medical equipment pulls a fair amount of power. I don't think a photo-voltaic system with battery backup, could do it...(but I could be wrong---all it takes is money)

And I'm ignoring the fact that the Homeowners Association would look dimly on a system on our roof.

So, the natural gas genny for us is a reliable and affordable solution.

As a side note, the guys who did the installation told me that 80% of the units they installed were for people like us--needing back-up power for medical devices.