I suppose that at some point the total solar generation in a street could exceed the capacity of the wires in the street.
but more interestingly, can a step-down transformer work backwards?
Scenario:
there are two "demands" both supplied from a single 11kV line. (for now ignore redundancy issues)
Demand 1 is industrial and is supplied by a dedicated 11kV to 415V transformer.
Demand 2 is a residential area also supplied through a dedicated 11kV to 415V transformer.
Now if the residential area installs solar panels feeding back into the grid, at some point the number of roof top solar panels will feed enough power back into that part of the grid within the residential area that the step-down transformer will be idle or working at some small fraction of its current carrying capacity. (Is a transformer's effectiveness affected by temperature? meaning that if the transformer has very little current passing through it, is that an issue? especially in terms of response time to a sudden increase in load.)
Then if the residential area installs more roof top solar, at some point the 11kV to 415V step-down transformer will need to "work backwards" to step the 415V solar generated power up to 11kV so that it can energise the 11kV line and can be used by the adjacent industrial demand.
Is this possible with the installed base of step-down transformers?
More generally, what is getting up my nose is the cross subsidy from renters and apartment dwellers -- who mostly can't access solar power -- to owner/occupiers of stand alone housing who receive subsidies to install solar panels.