Sorry to surface on old(er) thread but i'm curious if anyone has been successful going down this road. I'm scheduled for an 8kw Solar Roof install this fall along with 2 PW's and was contemplating adding a third to quality for the Step 3 SGIP rebate, but it really does seem like a long and deeply complex process. I'm not sure i'm qualified to be the test case, so any thoughts or insights would be great.
As an fyi, my permit application was just submitted to the city, so I imagine adding an additional PW would also set the project back a bit?
Your key statement is "solar roof from tesla". Tesla does not apply for the SGIP unless its equity and resiliency (special program), so you would have to try to navigate that on your own, and I only remember reading 1 or 2 people who did that here and its not "filling out a few forms".
If the question is "have people navigated filling out SGIP on their own" I believe the answer is "yes, but not many at all, and its a process that is not designed as such". If the question is "will buying a third powerwall from tesla get them to apply for it on my behalf" the answer is "no, tesla states they only apply for up to 2 powerwalls, and they are over the developer cap for those installs."
If the question is "can I get SGIP on 3 plus powerwalls?" the answer is "yes, if you go with a solar install company that is not over the developer cap for 3 powerwalls" (thus you would want to separate your solar roof into 2 different installs, tesla for roof, and some other company for powerwalls".
The next question would be "would I save any money by separating the install to get SGIP from a solar company that still has developer cap space for 3 powerwall installs?" The answer to that is very likely "no" because that third party non tesla installer is going to charge you such that, even factoring the SGIP rebate, the price for 3 powerwalls will net out to roughly what tesla is charging for 3 powerwalls without SGIP.
So, your only real recourse is to try to navigate it yourself, if you plan on going with tesla, and since you mention you want to be a test case, I would suggest that is not something you would likely want to try to accomplish.