Conditional PG&E PTO and inverter downsizing

[hiltxan]

I ran into another problem with my PTO because PG&E says I need a transformer upgrade, but in the meantime I can operate up to 12.67kw. I have 13.6kw DC panels and 2x7.6 inverters so the nameplate is 15.2kw and 2x powerwalls with a gateway. The CEC-AC rating is 12.38kw, which is below their 12.67kw limit.

Is it worth arguing with PG&E saying that I don't need a transformer upgrade? I brought it up to them already pointing out my CEC-AC is less than the limit, but they say they are still basing the size off of my 2 inverters which is 15.2kw. I wonder if the engineers or interconnection agent are just not understanding the calculation. Even on one of the PG&E FAQs they say they calculate the solar size off of the CEC-AC rating if its lesser than the inverter nameplate capacity.

https://www.pge.com/pge_global/comm...icles/net-energy-metering/nem2-sunset-faq.pdf

PG&E gave me several options:

1. Upgrade the transformer and have Conditional PTO. Please confirm if there are any meter access issues (gate, dogs, etc.). If there are, please provide the information of the person who can provide access (name, number and email.)
2. You may permanently downsize your inverter to no more than 12.67 kW with restudy fee of $300. Or withdraw and reapply with $145 fee with the new nameplate capacity.

I don't want to go with option 1 and drag it out with Tesla, I just want to get it over with. Tesla has been completely silent and I'm basically coordinating with PG&E all by myself at this point. I want to do this as quickly as possible without involving Tesla to redraw some SLDs and disconnect some panels and don't mind paying some extra fees.

For option 2, I'm not sure if a restudy will force me onto NEM 3.0. It seems that if I withdraw and reapply I will end up on NEM 3.0 so I probably won't go that route, but still waiting for PG&E to confirm this. Does anyone know if the Tesla inverter or gateway can even be electronically limited to output only 12.67 to the grid?

Thanks in advanced and I would appreciate any suggestions/guidance. By the way, this entire solar project has been one huge headache. It should not be this difficult to get solar in California. I also wish I knew what system I could size for my transformer before I decided on my system size and would've not exceeded it during the design process.

 

[cwied]

I don't think that your argument is likely to succeed. As I understand it, the CEC-AC rating is just a nominal size for your system. In reality, your system can push as high as your nameplate rating through the transformer. I have a 6.3 kW DC system with a 7.6 kW inverter and have seen production as high as 7.2 kW due to the cloud edge effect. From PG&E's perspective they need to size their transformer to be able to handle your inverters' peak output.

 

[hiltxan]

That’s what I saw too on my system. Sometimes I can hit 13.6kw for a brief moment if it’s cloudy which is more than the 12.6kw transformer limit, but I usually have 1-2kw draw during the day for my home.

I chatted with Tesla to see if they can electronically derate the inverters but the agents said it’s not possible. Tesla interconnection team said they asked the PG&E to reconsider the CEC-AC again so I’m waiting to hear back.

From PG&E standpoint, if they always went with the inverter nameplate then transformers will be always be oversized since inverters are sometimes oversized for the DC system. But then again you can’t always go by the home CEC-AC rating because then you’ll estimate too much production for a certain neighborhood on one transformer. The only logical sense is to take the lesser of CEC-AC or inverter nameplate.

If I do have to get conditional PTO, it requires Tesla to disconnect panels and submit a new SLD and also requires multiple PG&E inspections. I’m more worried about PG&E blocking my PTO since my panel is above a gas riser and enclosed in a closet…which is a whole another headache I’ve been trying to avoid. I wish I had known about the transformer limit since then I won’t have to involve PG&E at all.

 

[SoundDaTrumpet]

I recommend sticking with option 1 and be patient with the transformer upgrade. PG&E was fairly swift (~3 months) with an above ground transformer when upgrading to a 400A service.

I would avoid using the NEM2 sunset FAQ as the counter argument for transformer upgrades. The purpose of it was to limit changing system size. The NEM2 Sunset Webinar seems to suggest… that due diligence determining system sizing was supposed to make these projects as real as possible. I was very careful sizing my NEM2 Sunset Application of my paper concept project based on proposals.

Considering my solar system was off-line for 3 months for a panel arc fault issue, the wait will pay off. A new transformer will replace an aged transformer, so you might be doing a favor for your neighbors!

 

[BGbreeder]

Go for the upgrade. Trying to reason with several bureaucracies at once is a recipe for hair loss in my opinion...

 

[hiltxan]

Thanks for the advice. I guess I’ll go with the transformer upgrade and hope PG&E has mercy on my soul with the gas and main panel clearances.

 

[hiltxan]

Tesla said that both option 1 and option 2 will force me into NEM 3.0. I don’t believe this is the case? Tesla said that PG&E will not allow me to stay on NEM 2.0 if there is a transformer upgrade because I need to resubmit an application for both options.

Right now I’m not sure if PG&E or Tesla is correct. I called PG&E but they can’t answer my question since no one has any experience with conditional PTO. The PG&E agent thinks that as long as I don’t resubmit a brand new application I should be on NEM 2.0 but can’t confirm. Basically I’m kept out of the loop even though I asked to be updated but neither PG&E or Tesla seems to be interested in informing me of the status and I have to call and chat with both parties daily.

Does anyone know if a transformer upgrade puts you on NEM 2.0?

 

[holeydonut]

I think you'll want some feedback from @Redhill_qik on this (since he is literate and I am dumb). But my understanding is that there is a kind of fuzzy/vague language in the NEM 3.0 rules for what type of NEM 2 interconnection application qualifies for retroactive treatment after that magic April 14 cutoff. To add to the pain, the rules are different between PG&E, SCE, and SDG&E territory.

For NorCal, my understanding is that installers who submitted PV+ESS interconnection applications into PG&E's portal got to keep a place in line for NEM 2. The actual work didn't have to begin; but the project had to be designed. I think this probably kept @Vines really busy too heh.

So you can see the problem; the applications had to be somewhat fleshed out - they couldn't just be blank forms. Stuff like your kW size, number of batteries, type of panels/inverters/etc, and even a line diagram or permit application had to be included in the application to get a place in line.

If your system materially changes, my understanding is that it has to be re-submitted. The old NEM 2 PG&E interconnection portal was not an easy thing to navigate. From what I saw on the portal, once something got submitted... it wasn't possible to go back and edit it without re-opening it. I suspect since the PG&E developers never contemplated NEM 3.0 funny-business, when someone re-opens a NEM 2 application for editing today, that user is barred from re-submitting it.

Tesla may have experience from other installs to support their concerns that adjusting your inverter size will kick you out the NEM 2. I think you'll need something in writing from PG&E (or possibly even where PG&E makes the change for you) to amend your NEM 2 application without getting punted to NEM 3.

Edit: this is the language I got in my inbox from PG&E regarding my interconnection submission that at the time of the email was not yet submitted:

To qualify for NEM2, solar applications must be completed by 11:59 p.m. on April 14th. Applications completed after April 14th will be interconnected under the Solar Billing Plan and temporarily billed on NEM2 until the Solar Billing Plan is operational in PG&E’s billing system. We will provide more information in the coming months.

Double-Edit: here's the link to the new NEM 3.0 solar billing plan.

https://www.pge.com/pge_global/local/assets/data/en-us/solar-renewables/green-energy-incentives/solar-and-renewable-metering-and-billing/how-to-read-your-bill/nem-bill-overview.pdf?WT.mc_id=Vanity_solaroverview

 

[hiltxan]

Thanks for the information. I think Tesla is incorrect and I need to confirm with PG&E which options will keep me on NEM 2.0. I definitely now have to keep an eye on Tesla to make sure they don't do anything rash such as submitting a new application. I think option 1 with conditional PTO or option 2 with a $300 restudy option with a lower inverter nameplate should keep me grandfathered in NEM 2.0. Option 2 with an interconnection application withdrawal and $145 resubmission with a lower nameplate sounds like it will be put me onto NEM 3.0

It doesn't make sense that PG&E will force you onto NEM 3.0 if a transformer upgrade is needed. The whole point of submitting the interconnection application before April 14 was to let PG&E know that you plan to install a PV system of a certain size within the next 3 years. It's impossible to anticipate what equipment will be available thus they allow changes to the interconnection application as long as the size remains the same or lower. Also, to force customers onto NEM 3.0 because of a transformer upgrade just seems outright wrong - there's no way I could've known what my neighborhood transformer could handle unless I submitted the interconnection first and waited for PG&E engineering review.

I submitted my interconnection application and fee and received email confirmation in March. With that submission and fee, I feel like I'm guaranteed my system size under NEM 2.0. But who knows how shady PG&E is and if they'll honor it, maybe there are a bunch of fine print that I never knew....

 

[Vines]

From my understanding, transformer upgrades do not push one into NEM 3.0, even when begun under NEM 2.0.

This is where the utility has some discretion so being pleasantly persistent will pay dividends. I would go with the transformer upgrade personally.

 

[holeydonut]

...It doesn't make sense that PG&E ....

Lol... look at this guy... he still expects PG&E to make sense. After about 6 months of your PV+ESS project, you'll come around. PG&E only exists to not make sense. It's more profitable for them to not make sense.

BTW, did you actually agree to Option #1 before April 14 and get something in writing from PG&E that they would do option #1? I don't think PG&E has any legal/mandate to upgrade transformers to accommodate residential solar. If you didn't lock in option 1, it could be off the table now.

Upgrade the transformer and have Conditional PTO. Please confirm if there are any meter access issues (gate, dogs, etc.). If there are, please provide the information of the person who can provide access (name, number and email.

 

[hiltxan]

I just got an email confirmation from PG&E that both options will keep me on NEM 2.0. Engineers still are being conservative and calculating the nameplate capacity of the inverter, rather than the CEC-AC rating. I even pointed out to public data (CaliforniaDGStats) that Tesla solar systems are not in multiples of 3.8, 7.6, 11.4 etc. but they still won't budge.

I can downsize my inverter with a $300 restudy fee, or go for a transformer upgrade with conditional PTO. I'm going to go with a transformer upgrade since Tesla doesn't need to do anything. Again, I'm still hoping that a PG&E inspector isn't a stickler for my main panel above my gas riser.

 

[Vines]

I just got an email confirmation from PG&E that both options will keep me on NEM 2.0. Engineers still are being conservative and calculating the nameplate capacity of the inverter, rather than the CEC-AC rating. I even pointed out to public data (CaliforniaDGStats) that Tesla solar systems are not in multiples of 3.8, 7.6, 11.4 etc. but they still won't budge.

I can downsize my inverter with a $300 restudy fee, or go for a transformer upgrade with conditional PTO. I'm going to go with a transformer upgrade since Tesla doesn't need to do anything. Again, I'm still hoping that a PG&E inspector isn't a stickler for my main panel above my gas riser.

If your electric meter is in the no go zone you will be required to move it (EDIT either the panel or gas meter) if you replace the panel.

If you leave it alone, the existing condition won't trigger a rejection of the transformer upgrade. However if you install a new service panel or try a like for like swap, you will have to abide by the clearances here:

 

[hiltxan]

Yep, I've looked at the figure and read the fine print in details many times. I feel like a lawyer interpreting the code.

I didn't swap like-for-like or upgrade my electrical meter or panel, which was 200A to begin with. It was originally built, inspected and approved without the proper 36" clearances from the gas riser, and it's also enclosed inside a cubby that doesn't have enough workspace clearance - 2 violations that were probably ok back in 1998 when the house was built but not up to code today. Tesla almost didn't want to start the project on the day of install and waited 2 hours until the crew lead got an OK from a higher up to proceed due to these 2 issues.

I added a 125A breaker which connects to the gateway. Then all the circuits got relocated and spliced to a load panel which is on the other side inside the garage. There are no new conduit or electrical devices within 36" of the gas riser.

Technically, I should be grandfathered in, I'm worried that PG&E can still deny PTO once they see it and force me to bring it up to code.

Then there's this little thing I saw in the interconnection application. Tesla filled this out for me. Yikes.....so ambiguous and up for interpretation that can go either way.

 

[hiltxan]

The figure legend also says no existing electric meter / panel, including panels within closets in the footnote.

They installed it to this main panel. Pic below:

I would’ve been home free since PTO was usually just a formality, but now that I’m doing a transformer upgrade it seems like I’m risking everything due to a PG&E inspection. If PG&E does force me to relocate the gas riser or electrical panel, I’m guessing it’s at least another 20k+ of work because I have underground utilities.

 

[YRide]

If your electric meter is in the no go zone you will be required to move it (EDIT either the panel or gas meter) if you replace the panel.

If you leave it alone, the existing condition won't trigger a rejection of the transformer upgrade. However if you install a new service panel or try a like for like swap, you will have to abide by the clearances here:
View attachment 932122

@Vines couldn’t the OP have PGE install a slam shut valve on the gas meter and drop the clearance radius for conduit, equipment & dwelling openings (windows) down to only 12”?

Might not fix the workspace requirements though.

 

[Vines]

@Vines couldn’t the OP have PGE install a slam shut valve on the gas meter and drop the clearance radius for conduit, equipment & dwelling openings (windows) down to only 12”?

Might not fix the workspace requirements though.

I do not have any information that this is an option for a contractor.

It may be, but PG&E haven't responded to my requests on this option. I guess they want these for homeowners and other severe mitigation cases, but don't allow contractors to use these to easily fix every gas meter clearance problem.

 

[YRide]

I do not have any information that this is an option for a contractor.

It may be, but PG&E haven't responded to my requests on this option. I guess they want these for homeowners and other severe mitigation cases, but don't allow contractors to use these to easily fix every gas meter clearance problem.

Ok, so you’re saying it can’t be requested (at least with 100% guarantee) by a contractor.

But is it correct that the slam-shut does drop the setback from 36” to 12” for equipment, conduit and entrances (ie windows) to the dwelling?

My neighbor (in SJ) had their Tesla energy install team out here last week. They were a traveler team from Baltimore though (5 weeks, apparently Tesla sending teams in from around the country to attack the NEM2.0 backlog) and since they arent local they weren’t aware of “slam shut” valves for PGE.

Hopefully I didn’t misled them, but they were taking a bunch of pictures of my meter and we’re gonna run it by there mgmt, so they knew if when my install occurred, they could utilize space between my existing main panel and the riser, which currently is exactly 36”.

 

[Vines]

Ok, so you’re saying it can’t be requested (at least with 100% guarantee) by a contractor.

But is it correct that the slam-shut does drop the setback from 36” to 12” for equipment, conduit and entrances (ie windows) to the dwelling?

My neighbor (in SJ) had their Tesla energy install team out here last week. They were a traveler team from Baltimore though (5 weeks, apparently Tesla sending teams in from around the country to attack the NEM2.0 backlog) and since they arent local they weren’t aware of “slam shut” valves for PGE.

Hopefully I didn’t misled them, but they were taking a bunch of pictures of my meter and we’re gonna run it by there mgmt, so they knew if when my install occurred, they could utilize space between my existing main panel and the riser, which currently is exactly 36”.

I am saying my efforts to use these for a contractor haven't been fruitful. I cannot speak to any reduced gas meter clearances.

Can you point to where this slam shut valve is specified in the green book? Greenbook Manual Online

 

[hiltxan]

Unfortunately even the 12" rule won't work in my case - the meter is right above the gas riser. I should technically be safe since the pressure relief valve is outside of the cabinet, though when I first moved in the house I did notice a slight smell of natural gas whenever I opened the door. I called PG&E and it turned out there was a small leak that they fixed, but this was located after the gas riser and meter. It probably doesn't make me comfortable at night knowing that a leak can be enclosed in the closet, but that's how my house was built and adding solar probably has no implication on the long term risk of a gas explosion (all I did was add a circuit breaker and splice the original circuits to go to a backup load center). Maybe in the future I will discontinue the natural gas after my gas furnace and water heater dies.

I just signed the conditional PTO letter and started to export. I've been in contact with the field metering team who says they will come out to inspect the meter and start the transformer upgrade and confirmed that since it's a shared transformer, I won't be responsible for the costs of the upgrade.