Interconnection Agreement - Estimated annual production question

[brian.c]

I finally received my interconnection agreement, but something seems off. Under annual total energy production, it lists 1664kw, but my system should be generating substantially more. My system is 9.52kw, so am I missing something, or did they put in the wrong numbers?

 

[BGbreeder]

If PG&E is happy with it and they signed it, why does it matter?

FWIW: CEC-AC rating

CEC-AC Rating
The CEC-AC system rating is used to determine the eligibility of a solar system for the California Solar Initiative (CSI) Program. But even if you’re not in California, this rating is closer still to real world production. Therefore, it can still be helpful in your comparison shopping, and that’s why we’re telling you about it.
This rating uses the PTC-DC rating of the solar panels and multiplies it by the number of solar panels and the inefficiency introduced by the DC to AC inverter. The inverter efficiency is usually around 95% in case you’re curious. Here’s the basic equation:
PTC Rating x Number of Panels x Inverter Efficiency = CEC- AC Rating
As you can tell, we’re getting closer and closer to actual production values.

All the best,

BG

 

[dareed1]

Yes, they evidently forgot to enter in the kW size of the system, so the figure is off by about 9.5 times. As arnolddeleon can tell you, it is important that PG&E have the correct size, since they may refuse to credit you with power fed back to the grid above the amount they think you should be able to generate. I suppose the tricky point here is that you already had a 3.2kW system. I'm not sure how you get both systems entered into the PG&E system, but I think you need to be sure that they know the total is 12.7kW. If you retained NEM1 on the original system, perhaps the accounting would be done separately.

 

[arnolddeleon]

If PG&E is happy with it and they signed it, why does it matter?

FWIW: CEC-AC rating


All the best,

BG

Because PG&E will limit your export credit to your estimated production value. I know this first hand. PG&E has on record a much smaller value for my total PV install than I actually have. Most likely the error was introduced when I had Tesla install Powerwalls 3 years ago (I had two existing PV systems). Both Tesla and PG&E have been useless in fixing. Fortunately I've switched to more self consumption model so that has minimized my loses.

 

[brian.c]

Yes, they evidently forgot to enter in the kW size of the system, so the figure is off by about 9.5 times. As arnolddeleon can tell you, it is important that PG&E have the correct size, since they may refuse to credit you with power fed back to the grid above the amount they think you should be able to generate. I suppose the tricky point here is that you already had a 3.2kW system. I'm not sure how you get both systems entered into the PG&E system, but I think you need to be sure that they know the total is 12.7kW. If you retained NEM1 on the original system, perhaps the accounting would be done separately.

Thank you, that was what I was thinking, they forgot to add the 9.5. I will be moving both to Nem 2.0 so will need to find out if we need the combined or only the new. I am assuming only the new, since my last year usage was above and beyond what my 3.2kw system generated. I figure better to fix now then send off to PG&E and have them sit on it for 30 days before rejecting it.

 

[BGbreeder]

The form says "and/or", so CEC-AC alone would appear to be sufficient.

 

[brian.c]

If PG&E is happy with it and they signed it, why does it matter?

FWIW: CEC-AC rating


All the best,

BG

It has not been approved, I just received to sign it. I will let Tesla know tomorrow, hopefully can get it fixed quickly.

 

[hayhayday]

1664kwh was the previous value per kw on old interconnect form so might be a default(1kw) value that they forgot to fill in

 

[sorka]

If PG&E is happy with it and they signed it, why does it matter?

FWIW: CEC-AC rating


All the best,

BG

Because he won't get credit for export or his export will be severely capped.

 

[brian.c]

Spoke with an advisor today, he said he did not believe this would make any difference but would reach out to the interconnection team. If they capped my export to 1kw, that would make the system pretty much useless in terms of a reasonable ROI. I am wondering if they are purposely doing this since my system size is nearly double my usage when using those calculations.

 

[aesculus]

I had the exact same issue. Get it fixed.

The other problem I had was the energy consumption. Tesla fudged the number to state I would increase my usage because they did not want to try to figure out what my actual usage was since I had solar and PWs installed already. They could have just looked at the data they collected via the PW app. :-(

 

[sorka]

Spoke with an advisor today, he said he did not believe this would make any difference but would reach out to the interconnection team. If they capped my export to 1kw, that would make the system pretty much useless in terms of a reasonable ROI. I am wondering if they are purposely doing this since my system size is nearly double my usage when using those calculations.

And just to be clear, they don't cap exports to instantaneous power but to watt hours so not kW. but kWH.

 

[brian.c]

I just wanted to update that this issue was resolved. I received an email later that day from the advisor I spoke with on the phone explaining, that signing was just to get things moving, and the document would be updated before sending to PG&E. Today I was notified that the application has been sent to PG&E, and the document was updated to reflect the proper size. The updated document does list both solar arrays in the totals.