So I was under the impression that there were 3 things which contributed to maintenance.
disasters, dust and time.
I couldn't find anything on the finer details of maintenance mechanics, anywhere, they are not laid out on the wiki or in any previous post that I could find.
So i did some testing and the 3 factors of maintenance seem to be disasters, dust and time.
Buildings in domes need maintenance, so why would a Stirling generator not need maintenance, it would not get extra maintenance from dust but it would still be subject to the basic maintenance from time.
the fact that the buildings appear more dusty the fuller their maintenance bar gets was simply a graphics feature, this wasn't representative of game mechanics.
also you can put solar panels in domes, why not Stirling generators, wind turbines can't because well no wind, I'm not sure if a fusion power plant would fit, I never checked.
It is practical to build a vacant basic dome to house your Stirling generators if those are your primary power providers if you get a lot of dust storms.