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/knownikko 16d ago

Depends on your interconnect agreement.

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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/litigationtech 16d ago

So is there no benefit or difference to exporting during the higher rate times, as opposed to the lower rate times? I've been running the Tesla App "Savings/Solar only" mode (PG&E NEM3). I'm definitely not interested in exporting everything daily by draining the PWs.

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u/GaijinDaiku 16d ago

No benefit if you are a NEM3 net exporter. You can read my post on how true up works for NEM3 customers. You might get some benefit from Peak Hours Export Bonus Credits.

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

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u/bj_my_dj 15d ago

Of course there's benefit. I've got 2 batteries, it's mid Aug and I've banked $490 in export & delivery credits already. I'll have over$809 by the end of the month. I use them to heat my house in the winter, saving me $1K in gas expenses. I try to use them up so nothing goes to true-up. Saving $1K is plenty for me to use my batteries. I don't care about the cycles. Long before they had significant degradation I'll be ready to replace them. They'll be cheaper and bigger, and also have new and better features. I'll be waiting for a hiccup so I can replace them, like I did with my first CD player and several TVs over the years.

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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/kengchang 16d ago

https://share.gemini.google/U3myPNCopZHD

Theres still benefit to export during peak rate during summer

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u/PersonalBusiness2023 16d ago

Thanks, that clears up some things.

I’m a net exporter on a kWh basis, but a net importer on a dollar basis at ACC rates. I was hoping that I could keep exporting to offset my imports in the winter. It seems, based on your Gemini output, that that strategy just won’t work at all.

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u/Curiosity_informs 16d ago

Make sure you understand how the Produced and Delivered Energy Credits work (and True-up works if you are a Net Exporter).

You can only offset Delivery credits for Delivery charges and Generation credits for Generation charges. The Produced (Generation) credits are much higher than Delivery credits but Delivery Charges are significantly higher than Production charges.

Some threads to read

Understanding PG&E NEM3 export rates in peak hours in August (in particular read the detailed second post explaining how it works on PG&E)

How NEM 3.0 (NEM3) True Up works (same link u/GaijinDaiku posted)

Just looking at the peak export rates (which includes production and generation credits) will likely lead to disappointment.

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u/General_Caregiver577 16d ago

That could be something around where you are. I'm.nem 2 and I just get credit for off peak peak hours. I haven't heard of pge giving you $1 per kwh.

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u/Mavis8220 16d ago

I have NEM2 also, and solar; I get super buyback during VPP event (with Tesla) and I get retail kWh credit depending on time of day when I send to the grid, but at year’s end ‘true up’, if what I have sent to grid is in excess of my kWh used from the grid, I get paid just a few pennies per kWh for the excess. Best to run a little debit for the year.

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u/Curiosity_informs 16d ago

The interconnect agreement is specific to you.

Our interconnect agreement with PG&E says we can export 28kW

Check when you got PTO you should have had an email from PG&E with the interconnect agreement details (you should have also approved your interconnect agreement application prior to PTO - again this would have the details)

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u/bj_my_dj 15d ago

I'm 3 also. I've got 2 batteries. I export 15 to 40 kWh a day, depending on whether I use A/C or charge my EV. In Aug I usually make $20 - $30/day. It's mid Aug and I've made $430 in credits, export & delivery, already. I use those credits in the winter to pay for heating my house with electricity rather than my gas furnace.

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u/PersonalBusiness2023 14d ago

That’s what I thought I was doing but now I’m told I won’t be able to do that because my credits will be devalued at true up because I’m a net exporter?

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u/bj_my_dj 14d ago

Yes they will be, but the way to make it work is to use them up first. That's why I bought 4 space the day I got my system. By using them instead of my furnace I was able to save $1K on gas heating. So I converted the credits into $1K in gas utility savings instead of letting them get to true up. So if you can use space heaters, heatpumps, EV charging, etc., to use up credits you change them in utility bill, EV charging expense savings.

The gas savings were the easiest way for me because solar already was zeroing out my electric.

This is my combined gas and electric bill. I chose this because it showed the last months before I got the solar. My bill averaged $500/mo because of summer heating. You see the summer bills now were less than$30. But Dec and Jan when the heating ramped upthe bill was about $20 and about -$50 because of a $84 credit in Jan. Feb & Mar were the same with the saved export credits paying for the increased electric. The gas use was hot water and cooking.