The only change needed for solar users is a different meter swapped at the house that supports bidirectional metering. Solar power at the residential level only lowers overall demand in the neighborhood and on the grid, and in the very rare case where the net solar production exceeds the entire neighborhood's demand, PEC could choose to simply not use that excess (curtailment) and the meter at each person's house would accurately reflect that with no upgrades needed (Texan power utilities are not required to buy back excess solar). So the added cost to PEC is entirely optional. At its worst PEC was only crediting almost half of the power they were reselling from solar users (from originally a simple net credit), although they've thankfully been starting to backpeddle on that.

Honestly, I would prefer they simply charged the cost of swapping meters and adjusted the flat infrastructure fee for solar users (when necessary) for cases where upgrades are needed in neighborhoods with excess solar generation. Instead, PEC is able to resell solar power for a very significant profit with their current rates.