That depends what "generation" includes. It probably also includes the transmission and stepping up and all of the equipment to deliver it to the distributor. I

That depends what "generation" includes. It probably also includes the transmission and stepping up and all of the equipment to deliver it to the distributor. If you are grid tied, you are still using that system as a backup at minimum and should contribute to its upkeep. Therefore you should be paid accordingly. I don't think there is much objection to paying for solar excess at the bulk rate.