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PG&E Customers with 3 or more PWs: Interconnection NEM2, NEM2-MT, or NEM2-PS

holeydonut

Supporting Member
Jun 27, 2020
1,512
884
East Bay NorCal
Another question for the folks with NEM2-MT... what did you input for section 2.7 under "grid export"?

Did you put the ESS there even though Powerwalls cannot export to the grid?

upload_2021-2-10_23-22-36.png
 

h2ofun

Active Member
Aug 11, 2020
2,457
419
auburn, ca
The information a PG&E representative gave me 2.5 years ago, and which may not be accurate, was that NEM-MT vs NEM-PS was a billing issue, not a regulatory issue. There are different regulatory categories more finally divided than NEM-MT vs NEM-PS. For example, my interconnection agreement is limited to 10 kW of storage, or 2 Powerwalls.

Cheers, Wayne
Reading the nem2-mt, should like any with solar and or batteries would be on this plan?
 

holeydonut

Supporting Member
Jun 27, 2020
1,512
884
East Bay NorCal
Reading the nem2-mt, should like any with solar and or batteries would be on this plan?


I think NEM-PS was supposed to be the one that normal homeowners would get if they have solar and batteries... it has much lower fees and less BS. Moving people to MT just seems like an easy way for PG&E to get all PV+ESS installed. But there are a lot more fees involved which likely helps PG&E offset their "losses" when customers move to the combined self-generation tech to bypass their peak rates.

https://www.pge.com/pge_global/comm...Paired-Storage-Frequently-Asked-Questions.pdf

Check out these tariff/fees for NEMMT... normal NEM2 is $145.
upload_2021-2-11_4-36-25-png.635622
 

holeydonut

Supporting Member
Jun 27, 2020
1,512
884
East Bay NorCal
good point. Anywhere it says you PW's cannot be charged from grid?

That's page 27 (Appenidix I) of the PDF you linked. If the first box is checked technically you can't grid-charge. I'm trying to get the form completed with the second box checked which just limits grid charging to non-peak times.
 

h2ofun

Active Member
Aug 11, 2020
2,457
419
auburn, ca
That's page 27 (Appenidix I) of the PDF you linked. If the first box is checked technically you can't grid-charge. I'm trying to get the form completed with the second box checked which just limits grid charging to non-peak times.
The way I am reading this is we do not have any storage/battery that is NEM eligible. So, with no storage, then section I would not seem to apply.
 

holeydonut

Supporting Member
Jun 27, 2020
1,512
884
East Bay NorCal
The way I am reading this is we do not have any storage/battery that is NEM eligible. So, with no storage, then section I would not seem to apply.


Yeah, that's why I think section 2.7 is important to get right. I think it's incorrect to fill in section 2.7.1 with the Powerwalls as part of the Exporting. I think Powerwalls should go on the excluded list under 2.7.2.

If the Powerwalls are excluded, then I agree they wouldn't be part of the NEM eligible equipment... and it wouldn't matter what is entered to Appendix I.

But as it stands, I can't get Sunrun and PG&E to agree that Powerwalls are "non exporting" equipment. They want me to put the Powerwalls on there as part of the gross/net system as well as exporting equipment. I think this would put the Powerwalls in scope of being NEM eligible so I have to check the correct box around whether they could take energy from the grid.
 

wwhitney

Member
Nov 2, 2017
858
1,121
Berkeley, CA
So, I'm not following this thread very closely. But a little reading of Rule 21 and the NEM2 tariff tells me the following (where I may be dropping some 2s, i.e. some of the NEM should be NEM2):

- PV <= 30 kW, Storage <= 10 kW (2 Powerwalls) means Small NEM-PS. This applied to me (well, the NEM1 versoin), but this thread is about more than 2 PWs.
- PV <= 30 kW, Storage <= 150% PV means Large NEM-PS. Except that the 150% of PV limit is suspended through August 15, 2023.
- PV <= 30 KW, Storage > 150% PV means NEM-MT, multiple tariff; the interconnection has to be treated as two separate systems, the PV under NEM and the storage as a separate non-export storage

For anyone trying to decipher this, check out Table 11.2 of the NEM2 tariff, PDF page 33 of 40.

I wonder if some of the hassle occurring in this thread is related to a mistreatment of an interconnection as in the 3rd category, rather than as in the second category, i.e. prematurely enforcing the 150% PV limit.

What is clear to me from my non-comprehensive scanning of the two documents is that they say that after August, 2023, if you install, say, 15 kW of PV and 25 kW of Storage (5 PWs), then you are definitely under NEM-MT (Storage > 150% PV), the Storage has to be configured as non-exporting, and you owe an $800 interconnection fee (instead of or in addition to the $145 fee?)

I have the impression that until August 15, 2023, the $800 fee is not supposed to be charged, but I stopped cross checking things before I could confirm that.

Cheers, Wayne
 
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Reactions: BGbreeder

holeydonut

Supporting Member
Jun 27, 2020
1,512
884
East Bay NorCal
Thanks Wayne.

For reference, I pasted the image of table 11.2 from the PDF you cited below.

It seems like any reasonable PV + Tesla Powerwall installation is going to fall under this new NEM2-MT instead of NEM2-PS. Even though there's a thin window to get a NEM2-PS to work, it may require that NGOM compliance or non-export relay installed. And I feel like PG&E isn't ready quite yet to grant blanket exemptions for Tesla Powerwalls for this PS-compliance.

So, assuming I do have to use NEM2-MT (boooo), I haven't been able to get any explanations from Sunrun or PG&E regarding:
1) Whether there is a $800 interconnection fee today
2) Who pays this the interconnection fee if it is $800 instead of $145
3) Whether there are any other one-time tariffs or fees
4) What the impact is to the recurring NBC's on each monthly statement or NEM true-up for people on Mt vs PS
5) Whether I'm supposed to disclose the Powerwalls under the NEM2-MT form section 2.7 as "exporting equipment"
6) Whether I'm allowed to check the second box under Appendix I in the NEM2-MT form
7) Whether I really need to add PG&E to my homeowners insurance

The other stupid thing about the table below is that it's for systems that are not "100% REGF Charged" a Renewable Electrical Generation Facility = (REGF). So 99.999% of the time my Powerwalls will be REGF and only take power from my solar. In the 0.0001% of the time that a Stormwatch comes in, then yeah, it'll take power from the grid.




upload_2021-2-11_11-57-23.png
 

BGbreeder

Member
Jun 19, 2020
235
129
Bay Area
Thanks for sharing. I'm sorry that you are being forced to go through all of this,

This seems so very "square peg / round hole" especially in view of all of the other installations that have taken place.

All the best,

BG
 

h2ofun

Active Member
Aug 11, 2020
2,457
419
auburn, ca
Thanks Wayne.

For reference, I pasted the image of table 11.2 from the PDF you cited below.

It seems like any reasonable PV + Tesla Powerwall installation is going to fall under this new NEM2-MT instead of NEM2-PS. Even though there's a thin window to get a NEM2-PS to work, it may require that NGOM compliance or non-export relay installed. And I feel like PG&E isn't ready quite yet to grant blanket exemptions for Tesla Powerwalls for this PS-compliance.

So, assuming I do have to use NEM2-MT (boooo), I haven't been able to get any explanations from Sunrun or PG&E regarding:
1) Whether there is a $800 interconnection fee today
2) Who pays this the interconnection fee if it is $800 instead of $145
3) Whether there are any other one-time tariffs or fees
4) What the impact is to the recurring NBC's on each monthly statement or NEM true-up for people on Mt vs PS
5) Whether I'm supposed to disclose the Powerwalls under the NEM2-MT form section 2.7 as "exporting equipment"
6) Whether I'm allowed to check the second box under Appendix I in the NEM2-MT form
7) Whether I really need to add PG&E to my homeowners insurance

The other stupid thing about the table below is that it's for systems that are not "100% REGF Charged" a Renewable Electrical Generation Facility = (REGF). So 99.999% of the time my Powerwalls will be REGF and only take power from my solar. In the 0.0001% of the time that a Stormwatch comes in, then yeah, it'll take power from the grid.




View attachment 635918
just makes no sense when the PW's are not generators
 

holeydonut

Supporting Member
Jun 27, 2020
1,512
884
East Bay NorCal
just makes no sense when the PW's are not generators

It's because Powerwalls are not 100% REGF charged. I think if you somehow turned off Stormwatch (like permanently through some trigger in the hardware), you could just land under normal NEM2 rules.

The irony is that pretty much the only reason a Stormwatch ever kicks in is when PG&E threatens PSPS events. So if PG&E were actually providing power without shutting down for safety reasons all the time, your Powerwalls would be 100% REGF.

Edit: I just found this older thread on TMC talking about NEMMT:
PG&E Letter - Paired Storage Billing Update

I guess for these homeowners who got moved onto NEMMT, the primary focus was for PG&E to put a policy in place so that a homeowner who exported way more than their normal usage couldn't bank those export credits at peak rates in their NEM calc.

So the NEMMT's #1 objective seems to be to protect PG&E from the edge case of a homeowner bypassing all of Tesla's control system software. PG&E won't be at risk if someone uses their Powerwalls as grid export devices to generate energy credit (especially during peak time).
 
Last edited:

holeydonut

Supporting Member
Jun 27, 2020
1,512
884
East Bay NorCal
I don't quite follow--the hardware is capable of exporting to the grid. The only thing stopping it from doing so is software.

Cheers, Wayne


There are a lot of things that are capable of potentially unsafe activity if used incorrectly. I think it's weird PG&E is worried about the edge case of the PW's spazzing out and becoming massive export systems. IMO the UL listing for the PW's being a Power Control System with export controls ought to sufficient.
 

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