[kkfx]

It's worst actually, at least in France, if you inject to the grid you have to pay an "energy transport fee", even if you inject for free (only recently self-made systems are allowed to sell energy, before they can only donate or not inject at all) and the injected energy is now paid less than the cheapest price to the customers (6 cent/kWh for ground based p.v., 10 cent for on-roof p.v.). So well, we do not harm large utility business.

What harm on scale is the variable output especially from small p.v. utilities built out of incentives NOT personal power plants, the grid is sized with some large power plants serving a large set of customers, their absorption vary but if the grid is vast (and not too vast) enough variation tend to be slow on average, let's say 50MW PP experience 100-200kW demand variation in very short time. They can compensate easily keeping the grid frequency stable. With a significant amount of grid injecting p.v. variation might be MUCH bigger creating significant stability issues where injection goes up too quickly making the frequency skyrocketing and large PP can't decrease their output fast enough risking disconnection witch in turn might put large p.v. plants offline suddenly creating a cascading effect of large blackouts.

That's the real issue with grid-connected and tied renewables and another reason why we need to go toward self-consumption NOT injection.