As a renter, I'm moderately more in favor of utility-scale solar subsidies rather than subsidizing private solar. It seems like another way to make the arrangement more "fair" is to subsidize private solar, but credit the grid up to the original grant's amount. In other words, in the GP's case, they would only get $1000/year in free money for 15 years instead of 20.

(This is very low on my list of things that I care about, to be clear.)