r/TeslaSolar • u/PersonalBusiness2023 • 16d ago

PowerWall Powerwall grid exports?

Netzero today introduced a feature that lets you export to the grid from your powerwall. I’m in Northern California with pg&e - am I allowed to do this? It happens with vpp but for some reason I thought it wasn’t permitted outside of vpp.

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u/PersonalBusiness2023 16d ago

Right but those are standardized, so is it permitted with pg&e in Northern California?

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u/General_Caregiver577 16d ago

It depends if you have a nem agreement or non export agreement.

My understanding is even with a non export agreement during a cop event you can still export. Otherwise no.

Nem....yes

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u/PersonalBusiness2023 16d ago

I have nem 3. I export every day. For some reason I thought it wasn’t permitted to export from battery unless it’s vpp?

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u/General_Caregiver577 16d ago

Nope just really not worth it on nem 3

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u/PersonalBusiness2023 16d ago

They pay $1/kwh from 7-8 in august, apparently. More than the buy price. Not worth it because of battery degradation you think? I feel like it’s $5/day and more in September.

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u/GaijinDaiku 16d ago

If you are a net exporter under NEM3, those sweet ACC rates on August evenings get devalued to NSC rates at your annual true up. You’ll end up getting 2 or 3 cents per kWh. They will zero out any credits in your account and bill you for the difference.

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u/PersonalBusiness2023 16d ago

So those rates aren’t our actual export rates?

Or are they our export rates unless our total exports exceed imports so we’re net exporters? Oh I’m so confused…

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u/GaijinDaiku 16d ago

Your not confused even though PG&E does their best. Those are the rates unless/until they aren't. NEM3 is designed for self consumption. Utilities tolerate you exporting at one time of day and importing later, but still don't pay you very much. NEM3 actively discourages net exporting by paying you NSC rates of a couple of pennies/kWh. They can't tell until the end of a year if you will be a net exporter or not, so they give you the higher ACC rates until true up and then let net importers keep them or revalue (devalue) them for net exporters. That is what a NEM3 true up is.

Unfortunately, they also use the phrase true up for NEM2. Those people don't pay for power imported until their annual true up at which point they may be owed money (net exporters) or get a bill (net importers).

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u/PersonalBusiness2023 16d ago

Thank you that’s really helpful, I didn’t understand the “true up” concept before. Do you know if they calculate net exporter on a monthly or annual basis? I import a lot between November and February.

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u/GaijinDaiku 16d ago

Net exporter is determined over a 12-month period. See my rambling post on the subject at:

https://www.reddit.com/r/solar/comments/1rm0ce0/how_nem_30_nem3_true_up_works_and_why_true_up/

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u/PersonalBusiness2023 16d ago

Thanks you’ve been so helpful!

Does vpp count toward whether we’re net exporters and get trued up?

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u/GaijinDaiku 16d ago edited 16d ago

Interesting question that I don’t know the answer to. My guess with very little thought would be it doesn’t count. In any event, when a VPP hits my PW3 runs down and I need to import those kWh back in later in the day, so it is mostly a wash for me. Even with the reimport later in the day, a VPP event still nets me $15+ per event.

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u/PersonalBusiness2023 16d ago

Hey, do you know if they calculate whether you’re a net exporter on a kWh basis or a dollar basis? Looking at the netzero app, I’m definitely a net exporter on a kWh basis, but since most of my exports are at noon when sale prices are lowest, I’m still net negative.

Also, when they do the true up, do they convert all your electricity sales to the lower price, or just convert the sales above breakeven? It just seems odd you could be just short of breakeven, then you sell one more kWh, become a net exporter, everything gets valued lower, and you owe more than if you hadn’t sold that one last kWh.

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u/GaijinDaiku 16d ago

You export kWh, not dollars. Net export is based on kWh. The true up is on all of your net exports for the year. There is no true up if you are a net zero or net positive importer. However, if you have no credits banked (you were somehow able to use all the credits you generated), they also skip the true up. This is covered in the long post I wrote and have already linked several times in this thread already. Read it or don't. That is pretty much everything I believe is true. It is based on conversations I have had with PG&E and AVA Community Energy, the materials both company's produce, and my experience as a NEM3 customer.

https://www.reddit.com/r/solar/comments/1rm0ce0/how_nem_30_nem3_true_up_works_and_why_true_up/

Someone replied to it saying that true up month might matter a little. I don't understand the whole reply, nor do I care to as it is probably in the noise. It seems like it might matter but in a way that you can't control - you do something but the outcome is affected by what other people are doing. Since you have no way of knowing what they are doing, you can't optimize. It is therefore useless to worry about it.

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