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Operating Solar/Powerwall before PTO

aarshad81

Member
Oct 8, 2020
7
0
Castro Valley, CA
Hey,

I live in the Bay area and am getting my Solar and two powerwalls installed this Tuesday.

i am wondering would i be able to use the solar energy off grid before PTO or is this not allowed ?

also in case I can make it work, how does this work since i won't have paid Tesla since after inspection.
 

getakey

Active Member
Jan 28, 2020
1,452
475
95762
I had solar and PWs installed by 3rd party. Also they were installed at separate times. In both instances, I operated connected to grid before PTO. I didn't even know in the Solar install. I got PTO a few days after install and called installer to turn it on. They said it was likely already turned on. I checked and it was. In PW case, I asked if they could turn it on and they did. Did not get PTO for a month or so
 

mnsweeps

Member
Aug 3, 2019
555
141
Los Angeles
My install of 8.16kwh + 2 Powerwalls is on Monday 10/19. Tesla called today to confirm a lot of things and I asked him if I am allowed to test for a few hours. He said 10 hours of testing is fine with SCE.
 

gpez

Member
Apr 25, 2019
737
606
USA
We get a surprising amount of "can I operate my system before I receive permission to operate it?" questions on this board...

Can you operate before PTO? Probably
Should you operate before PTO? Probably not

Unless you're fully disconnected from the grid turning your system on before PTO risks:
a) Operating with a defect that the inspection may find, which could result in damage or worse
b) Violating your interconnect agreement with your utility, potentially voiding your contract and preventing you from using your system in the future

Personally I wouldn't risk it. There is a reason why PTO is PTO.
 

holeydonut

Supporting Member
Supporting Member
Jun 27, 2020
2,268
1,648
East Bay NorCal
I meant more like off grid, since i will have two powerwalls. Based on my usage my system should be able to keep me off grid (12.24 plus 2 powerwalls)



If you flipped the main breaker on your home, I'd imagine the utility would have no idea what you were doing. So if you don't tell us there won't be anyone to tell PG&E right?
 
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wjgjr

Active Member
May 11, 2020
1,349
1,060
Silver Spring, MD
I meant more like off grid, since i will have two powerwalls. Based on my usage my system should be able to keep me off grid (12.24 plus 2 powerwalls)
There are different perspectives on this, but in the end, the decision is yours since only you will face any potential consequences. As such, definitely review the agreements you signed with your utility and city/county to understand what they say.

Different state and utility, but I did operate off grid once the safety inspections (done by the county) were complete and prior to PTO. I carefully avoided ever having the system running unless the service disconnect was off, to avoid any grid interaction.
 

jrweiss98020

Tessa's Tesla
Jan 9, 2020
481
353
Edmonds, WA
I ran mine for 2 days before PTO with the main breaker opened. it was summertime, so plenty of power to run the house overnight. IMO it's a great way to test the system.

Do NOT run the system in a configuration that could push power to the grid, because your meter may object. Some meters are equipped with anti-tamper routines that record power going TO the grid as power coming FROM the grid...
 

sorka

Well-Known Member
Feb 28, 2015
8,283
6,246
Merced, CA
We get a surprising amount of "can I operate my system before I receive permission to operate it?" questions on this board...

Can you operate before PTO? Probably
Should you operate before PTO? Probably not

Unless you're fully disconnected from the grid turning your system on before PTO risks:
a) Operating with a defect that the inspection may find, which could result in damage or worse
b) Violating your interconnect agreement with your utility, potentially voiding your contract and preventing you from using your system in the future

Personally I wouldn't risk it. There is a reason why PTO is PTO.

I didn't realize PG&E comes out and does a physical inspection.
 

BrettS

Active Member
Mar 28, 2017
2,141
2,566
Orlando, FL
If you flipped the main breaker on your home, I'd imagine the utility would have no idea what you were doing. So if you don't tell us there won't be anyone to tell PG&E right?

Operating off grid like that for extended times is absolutely detectable by the utility because your house will suddenly be drawing no power for extended times and your monthly usage will significantly drop. Now, whether anyone will actually bother to look at your usage or will care even if they do is up for debate. But it would definitely be easily detectable by the utility.
 

gpez

Member
Apr 25, 2019
737
606
USA
I didn't realize PG&E comes out and does a physical inspection.

I don't know about PG&E as they are not my utility however my utility absolutely required an electrical permitting inspection to be completed by my city and then certified as complete by my installer as part of the interconnect agreement completion and PTO. Here is a snip of the email they sent myself and my installer (not Tesla but Tesla certified):

Your application for Net Energy Metering has been approved. We are now awaiting your Certificate of Completion.

The electrical permit number, issuing jurisdiction, and date of complete generating facility inspection must be provided prior to meter installation. The account holder or installer must notify the Company that the Generating Facility has been installed and inspected in compliance with local building and electrical codes.

Please upload a certificate of completion to the portal and be sure to include the following text:

“I certify that the Generating Facility located at _____________________________ has been installed and
inspected in compliance with local building and/or electrical codes. I have obtained electrical permit
number _______________________ from the following electrical authority, __________________________,
and the Generating Facility passed electrical inspection on __________________________.”
 
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wjgjr

Active Member
May 11, 2020
1,349
1,060
Silver Spring, MD
I don't know about PG&E as they are not my utility however my utility absolutely required an electrical permitting inspection to be completed by my city and then certified as complete by my installer as part of the interconnect agreement completion and PTO. Here is a snip of the email they sent myself and my installer (not Tesla but Tesla certified):

Your application for Net Energy Metering has been approved. We are now awaiting your Certificate of Completion.

The electrical permit number, issuing jurisdiction, and date of complete generating facility inspection must be provided prior to meter installation. The account holder or installer must notify the Company that the Generating Facility has been installed and inspected in compliance with local building and electrical codes.

Please upload a certificate of completion to the portal and be sure to include the following text:

“I certify that the Generating Facility located at _____________________________ has been installed and
inspected in compliance with local building and/or electrical codes. I have obtained electrical permit
number _______________________ from the following electrical authority, __________________________,
and the Generating Facility passed electrical inspection on __________________________.”
By no means the exact wording, but our utility similarly required the proper permits (we had both a building and electrical permit) were pulled and approved by the county. What seems to vary is in some cases, the utility will send somebody out to physically inspect the system, while other utilities rely on the city/county inspections. The latter was the case for us (though the utility officially had a right to inspect, but apparently never does.)
 

charlesj

Active Member
Oct 22, 2019
1,270
296
Monterey, CA
I didn't realize PG&E comes out and does a physical inspection.
When I installed my solar panels in 2012, city inspected, then PG&E came out to give me a bidirectional power meter and went on line.
When I had the 2 PW installed in May this year, the installer turned it on to check its operation. I left it on, city came to inspect some weeks later, all was good, except had to install more smoke detectors and CO detectors as the upgrade exceeded the amount where I would not have to have added them, perhaps under $1000. So, he said to send him pictures of all those installed, separate from PW. Same day I installed everything sent him pictures and passed in a few days without him coming back out.

PG&E never came back to check on battery.
So, If you have the whole system installed, it will get checked by installation crew make sure it works. I would check how much the battery is charged and on good sunny days I'd turn on the solar part and main break off so solar can charge batteries and house. Depending on how fully it gets charged first good day and how much house uses after sunset to next day when solar can take over again, I'd keep using it in self generation mode. And, if you have to you just turn on main breaker and perhaps solar breaker off, maybe.
PG&E only came out to swap meter for me the first time. Didn't check as the city is in charge of inspection, not PG&E.
The whole process went through power company in the first place for their engineers to see if any transformers needed upgrading, nothing more.
Get an early start.
 

jboy210

Supporting Member
Supporting Member
Dec 2, 2016
5,523
3,511
Northern California
I didn't realize PG&E comes out and does a physical inspection.
Depends. They did not do that for our installation. Our SmartMeter was already capable of bidirectional operation since they installed it 6 years or so ago.

we had final inspection by city, payment to Tesla, PTO app sent to PGE, and PTO approval.
 

3mp_kwh

Active Member
Feb 13, 2013
1,123
304
Boston
Do NOT run the system in a configuration that could push power to the grid, because your meter may object. Some meters are equipped with anti-tamper routines that record power going TO the grid as power coming FROM the grid...

Agree it seems without a net meter installed, your *excess* generation can be seen as consumption. That doesn't mean balanced household consumption won't stop, or slow, the meter.

Passed inspection 1 month ago. Utility still doesn't have final app. Today, I notice not only does system operation stop/slow meter, but that the Elster digital meter also has (instantaneous?) blinking arrows, for whether the utility is "receiving" or "delivering" power. At least, I can shift the arrows when I add/subtract loads. Even if meter isn't stopped, the odds of paying more in excess export than you would in total import (system off) are quite slim. [EDIT: They're slimmer, the smaller your system is, and more you can time loads to available sunlight.]

Having been a TOU customer in the past, and having clamp metered most of our loads, the next logical step is grabbing those old timers and stacking loads along the generation curve (10am-2pm, etc).

No idea, on utility retribution, or its ability to record momentary export (an obvious sign of generation, before PTO).
 
Last edited:

Ampster

Active Member
Oct 5, 2012
1,821
505
Kenwood, California
No idea, on utility retribution, or its ability to record momentary export (an obvious sign of generation, before PTO).
There are a number of possibilities. In one case a friend reported that his meter with PG&E reported generation when he inadvertently turned on the system before the PTO. What he later found out was in the case of PG&E that it was not something in the meter that was triggered when the PTO was issued. Instead it was a toggle in the billing software that was switched to calculate net generation.
That raises the issue posed by your question above? The only thing I know is that with certain battery installations that are subsidized, they do have the ability to review net generation. The data is there somewhere in their system. I have heard of several instances where production in kWh above the amount in a PTO has gone on persistently with PG&E and SCE and there has been no action. I suspect the accounting systems of these large utilities are ancient and some may not have programmed any exception reports which would compare the instantaneous output in Kwhs with the capacity of the inverter specified in the PTO.

I am not advocating that activity since it would violate the terms of a PTO and may be subject to penalties. My speculation is about the internal controls that may or may not be in place at a particular utility.
 

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