Most utilities (in the US, at least) deal with residential solar in a way that makes what you are trying to do a fun but pointless exercise.
While waiting for my solar guy to respond, here's AI's take (for what its worth, not much, I know...
Solar Charging vs. Grid Charging
Charge EV with solar (daytime)
Solar powers your car directly - You avoid paying full retail rates, which is better than earning low export credits
Charge EV at night (grid)
You pay retail price per kWh ...Full cost to you — no offset unless you have enough credits saved up|
Charging your EV during solar production hours is almost always better economically than exporting that energy and buying it back later.
Why Daytime Charging Wins
- You're using “free” energy rather than getting undervalued credits.
If your EV charger and driving schedule allow for daytime charging (even partial top-ups), it’s definitely worth optimizing for that.