Also it is too bad they make the manual transfer switch so hard to access. Even my generator 200A auto-transfer switch has a supplied insulated handle for doing a manual switchover between on-grid and off-grid.
I just re-read this and realized how completely unclear your statement is to me. Please clarify. Also, it might make sense for you to read my message before clarification, since perhaps it would help for you to understand. I think it's unnecessary for you to manually operate anything in the Tesla Backup Gateway (the Gateway).
I think this might be a mountain man vs urban thing. I've only very rarely seen backup generator transfer switches, and I've always found them to be problematic, since they are hard to automate in any type of seamless fashion with the grid. Is the transfer switch a double pole double landing switch with a disconnected middle switching section? That would be a type of isolation switch, isolating the grid from the backup generators. In that case, I go back to my original statement: that doesn't change; you just leave it on the grid side of your main service panel, and don't worry about it. If you want to change your "utility power" from PG&E to your generator, you can do so, at your manual whim. You don't need to touch anything in the Gateway during this switchover. You just do it. (It would be nice to turn off the connection to the Gateway (the breaker that goes to it) just so there's no errant weird power types flowing through during the switchover, but that might be a bad idea if you forget to turn it back on once the new power is up and wonder why the generator/utility isn't helping). The Gateway seems slow to reconnect the grid when grid is back (I mean by that the electrical source on what it thinks of as the grid, which could be your generator); "10 seconds" according to the installer, but I've experienced that and longer.
You would presumably only use your generator in situations in which it was needed. I think this would be an ideal case. It requires no more thought on your part than just having the PowerWalls and Gateway installed as normal.
You mentioned you hadn't yet hooked up your generators; I suppose you could wait until everything has been set in stone, but to me, theoretically, that wasn't necessary. Like I said, I don't know what kind of automatic transfer switch is available for generator switching, and in the case of a PowerWall backup system, you have half a day's notice anyway, so it's not like you have to remotely operate it (unless power drops at 6AM on your way to work and you have someone on life support and you don't get home til 9PM, in which case, of course, I'd look at this differently; someone would have to manually activate the transfer switch and the generator).
The problematic question is what to do with automatic generators: they would have to turn on only when the PowerWalls are low. I have a script that pulls the battery level % from the Tesla mothership via the Internet, but that presumes the Internet is up and running; I'm trying to find out how to read that % directly from the Gateway within the LAN, but haven't yet had luck. (There's a "provisioning" step that I am afraid to do.) If scripting can trigger, then that would work. A simple script-to-relay box would presumably do for most setups. Tesla has been very quiet about this, despite this being obviously a capability present in their hardware; if they expose the software properly, it would be trivial to set up an automatic generator startup when the batteries are at some level, such as 20%.
Edit:
Everything I own connected to the home power that generates electricity does so matching frequency. The PowerWalls do it. The SolarEdge does it. They're all modern electronics.
What I forgot is that generators come from an age when the utilities were deathly afraid of any competition, and successfully lobbied for generators to not ever include frequency matching hardware or software.
Your generators would obviously need to frequency match with the utility. This is a paradox in old-times speak because neither would be on at the same time. But in modern times, that isn't the case: the utility lives on, in echo, in the various home systems that continue running when the utility is down. The generator would get its frequency signal (i.e., a sampling line connected to something that is always up, such as your backed up panel) from your backed up panel. It would sync its frequency to your backed up panel, then allow you to connect; either it would have an automated switch, or a light to tell you that it has synchronized and it's time for you to manually throw your switch all the way over to generator mode.
And once again, I am wrong, I just realized; the Gateway already has provisions to re-match the frequency of whatever "utility" dog happens to be coming in to it: you can ignore this edit. The Gateway will just wait, having the PowerWalls skew to the correct frequency matching, then reconnect. That's probably what took so long last time I tested backup use. (It took longer than 10 seconds to reconnect. It was probably doing a very measured slow skew to correct synchronization.) That means the battery level should be pretty substantial when you start your generator, so the Gateway has time to match frequency and switch over. I'd like to know stats on how long this takes.
If the Gateway also uses frequency modulation to communicate with the solar inverters, then this could cause interference between two events; I wonder if Tesla properly programmed the Gateway for that. It also means frequency synchronizing the generators to the inside frequency would still be useful, unless it happens to pick the wrong side of a waveform timing and the Gateway prefers the other side, and they never match (that would be bad). The Tesla engineers could explain that, as well. It might just be easiest not to worry about it and let the Gateway handle the skewing and not have any sync line. Ideally, there would be a sync line to the generator (utility or whatever), and the Gateway would talk directly to the inverters in software rather than in power frequency modulation games.
