I don't know your specifics but when I installed in 2011 the grandfathering rule was for 20 years not 5. I can change voluntarily to another rate plan but if I do that I might not be able to revert back afterwards. In the meantime, SDG&E can't force me to change rates. Standard TOU rates would save me $50 a year if I believed SDG&E rate calculator. Every other rate structure would cost me significantly more than my current plan. Last year I actually ended up with a credit balance after the EV Credit, climate credit, and Reduce Your Use credits. I'm pretty sure that TOU rates won't benefit me in any meaningful way. I doubt that anyone really reduces their costs under TOU.
Just saw this, john.
To clarify, there are two different grandfathering periods at play with solar systems.
The first one is 20 years of guaranteed NEM participation when you first install solar. You won't lose that privilege for 20 years. This has nothing to do with pricing, just your ability to export excess energy.
The second grandfathering period is for 5 years, and that starts when your system is installed. This grandfathering lets you keep the legacy TOU periods (noon to 6pm peak time). In fact, the grandfathered version of the EV-TOU2 rate is called GEV-TOU2, and you might see that on your bill. After your 5 years is up, then you are moved to the non-grandfathered version of the rate with the new TOU periods (EV-TOU2).
Neither one of these grandfathering periods has anything to do with price...I hope that helps to clarify things....