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Anyone install 3+ Powerwalls in San Diego?

Posting this here as I did not get any response in the CA forum.

I’m looking into getting 2 or 3 Powerwalls. Spoke with one installer and they stated going from 2-3 is a big deal with SDG&E as it crosses the line from residential to commercial. One would need another meter behind the regular one to monitor self generation (SGOM?) and require additional things to be code compliant. I have no reason to doubt what they say, but I’ve seen others with 3+ PW’s in various locales and not a mention of this. Is this a SD thing? Is it less of a big deal than it seems? Getting anyone from Tesla to contact me seems impossible but that’s par for Tesla.

9.9 KW solar is already in place.
 

Ampster

Active Member
Supporting Member
Are you wanting to apply for the SGIP incentive? It may be a SGIP thing. I know that SGIP agreements contain restrictions on generation.

If not, I am of the belief that as long as you comply with building codes and do not send battery energy to the grid that you can add any generating capability behind the meter. There is language in most PTOs for solar that attempts to give a broad definition to the term "facility", which could under their interpretation mean behind the meter. I will try to find the thread where another San Diego poster essentially went off grid.
EDIT: Here is a link to that thread. The poster was bkp_duke at post #61 and he said he was considering another powerwall and going off grid. I don't know how many he has but you could message him about the details. His profile says he is from San Diego.
PG&E discontinuing EV-A rate
 
Last edited:

Ampster

Active Member
Supporting Member
I just heard that the new California fire regulations may have a restriction on the kWhrs of batteries in a garage or dwelling. Supposedly that is going into affect in 2020. The workaround is to have them some distance from the house. I don't have details yet. The initial report said the limit was 20kWh which would be one PowerWall. `
 

bmah

Moderator, Supercharger Hunter
Global Moderator
Mar 17, 2015
5,191
11,351
Lafayette, CA, USA
I just heard that the new California fire regulations may have a restriction on the kWhrs of batteries in a garage or dwelling. Supposedly that is going into affect in 2020. The workaround is to have them some distance from the house. I don't have details yet. The initial report said the limit was 20kWh which would be one PowerWall. `

New Cal fire code for Powerwalls?

Bruce.
 

KSilver2000

Active Member
Dec 23, 2017
1,368
2,438
CA
I just heard that the new California fire regulations may have a restriction on the kWhrs of batteries in a garage or dwelling. Supposedly that is going into affect in 2020. The workaround is to have them some distance from the house. I don't have details yet. The initial report said the limit was 20kWh which would be one PowerWall. `


Not trying to be an a$$, but these responses do not pertain to the OP's question. The OP was asking why there may be an issue with installing 3+ PWs. The new fire code pertains mostly to where and how batteries are located.
 

Ampster

Active Member
Supporting Member
. The new fire code pertains mostly to where and how batteries are located
You are correct about the fire code. It does, however contain a limitation on the amount of kWhrs that can be installed in a dwelling. It might be useful information to anyone thinking of installing more than one. The point being that there may be two hoops to jump through.
 

KSilver2000

Active Member
Dec 23, 2017
1,368
2,438
CA
You are correct about the fire code. It does, however contain a limitation on the amount of kWhrs that can be installed in a dwelling. It might be useful information to anyone thinking of installing more than one. The point being that there may be two hoops to jump through.

What limitation regarding the total kWh? Besides the 20kWh limit for installing on the wall, there really isn't a limit according to the new codes.
 
My setup has a NGOM (Net Generation Output Meter) which connects to my inverters and tells PG&E what I’m producing from solar in real time. That’s all it does.
Thanks. I went right to the source and called SDG&E. That's what they said - above 10KW, they require NGOM to ensure you are not selling battery power to the grid under net metering rules.
 
  • Informative
Reactions: liuping
I just got a reply from Tesla about an NGOM for my Powerwall order, see below. They are still working it out for customers in the PG&E service area. They offered to do the install without the NGOM but that could delay the interconnection into 2020, so I decided to get the NGOM which does add $500-$800 to the project.

I got an update on the CPUC ruling from our utility relation specialist:
https://www.pge.com/tariffs/assets/pdf/adviceletter/ELEC_5501-E-A.pdf

There’s a bit of a timeline mentioned in the letter but basically Tesla and the California Solar & Storage Association have been pushing back against PG&E’s decision on how to incorporate the CPUCs ruling as their suggested certifications are overly strict, where as other investor owned utilities in CA such as SoCal Edison and San Diego Gas and Electric allowed for pretty standard rulings that fall alongside the national electric code. We believe we’ve finally come to an agreement on the acceptable settings and what certifications they require and are expecting the U.L. certifications to come through sometime mid-December.
 
  • Informative
Reactions: Ulmo
I just got a reply from Tesla about an NGOM for my Powerwall order, see below. They are still working it out for customers in the PG&E service area. They offered to do the install without the NGOM but that could delay the interconnection into 2020, so I decided to get the NGOM which does add $500-$800 to the project.

I just had my 3rd Powerwall added to my existing system (10 panels @ 325 and two Powerwalls), and I went with the NGOM as well. I wanted to get this all sorted out as soon as possible, and didn't want to wait for whatever paperwork is needed to eliminate the NGOM.
 
  • Informative
Reactions: Ulmo

miimura

Well-Known Member
Aug 21, 2013
7,398
7,400
Los Altos, CA
Unless I misunderstand, part of the benefit of no NGOM is you can export to the grid from your battery and get net metering credits per the February decision. NGOM will limit net metering credits to just solar output.
I think you're misunderstanding it. Exporting battery energy to the grid is not allowed at all, NGOM or not. The NGOM just makes it easier to do the math because they can look at the main meter and the NGOM and see directly if you're exporting more than the solar is generating at any data time interval. Without the NGOM, they have to use a computational solar model to see how much your equipment should be generating and disallow NEM credits from there. For a Tesla Powerwall system without VPP enabled, this is all moot because the software won't let it discharge more than the household load.
 
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Reactions: Ulmo
I think you're misunderstanding it. Exporting battery energy to the grid is not allowed at all, NGOM or not.

I believe exporting from the battery to the grid is allowed, if the battery is only charged from solar. The link aboves states "In February, the California Public Utilities Commission (CPUC) approved a decision that will allow customers with energy storage systems to receive credits for storage energy that is sent back to the grid, as long as the storage system charges entirely from solar. "

Cheers, Wayne
 
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Reactions: Ulmo

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