If a PV installation only supplies your own house no problem - if it feeds in to power grids, there _must_ be some sort of process on how to regulate it, or else you might face grid collapse.
Grid collapse, the argument often used against solar.
Problem
Company's and shareholders failing to invest in a robust grid, thus maximizing short term profits . Now demanding Subsidy's.
Despite immorally high profits.
My solar system is Portable, needs no grid connection