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Tesla Virtual Power Plant in CA
- Thread starter power.saver
- Start date
Btw, apologies for the likely dumb question…does Tesla pay out for the VPP? Or is that through the utility (PG&E in my case)?
If the former, when and where?
If the latter…is that at annual true up? Can this only offset costs to net $0?
Will be interesting to see if tomorrow’s behavior is the same. VPP is longer (4-9pm). Battery discharge level should be lower than today’s. My 2x PW got down to 8% by the end of today‘s VPP event, had reserve set to 0%
But does it make sense that going the other way my powerwalls can grid charge at night at 21.6kW? Isn’t this stuff more or less bidirectional?
My interconnect seems to indicate 9.8kW.
For whatever reason my SLD/TLD has both powerwall+ inverters at 7.6kW.
Still unclear to he how Tesla installers arrived at 11.88 kW site export limit…I can’t find that anywhere…nor can get the math to arrive at that.
Nevermind…read the FAQ’s…
That said…now I’m concerned….
According to below…it would seem if I’m regularly dumping full rate export (11.9kW) from 4p - 9p…the VPP today, as well as the VPP tomorrow, are net zero offsets from “beyond typical behavior”.
I wouldn’t get any credit for VPP. Am I reading this correctly?
My system isn't charging now. I'm at 8% and raised my reserve to 30%. The app does show the event for tomorrow.
Edit: Hopefully it doesn't start charging while I'm asleep. Do you have grid charging enabled?
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First, I am not an expert on this. My understanding is that when the grid was built the calculations for transformer sizing was pretty simple with just needed to add up all of the downstream service loads with some large adjustment factor that assumes that everyone isn't pulling at 100% at the same time. Solar exports are similar, but since everyone's Peak production is at the same time I don't think they can use as large of an adjustment factor. The whole point of the Interconnect Agreement and the Permission To Operate process is to document the new generation site to ensure that it won't create a problem. There have been multiple posts here about IOU requiring systems to either be limited or requiring payment ($$K) to upgrade the local transformer.
Staying with the allowed export limit allows others on your transformer to also operate, both for solar and for VPP events. If you were allowed to export up to the maximum of your import than so could your neighbors and that could overload the transformer during a VPP event. There may be nobody else on your transformer with either solar or ESS, but the interconnect agreement is permanent that will very likely change over time although at a slower rate with NEM 3.0 rules.
I think that grid operators will likely have to re-examine their transformer sizing equations due to changing electrical usage with large continuous draws for EV charging that all start at midnight and now for those with ESS that are charging from the grid (I do not use this function).
It seems strange that Tesla would have installed two 7.6kW inverters with only 10.8kW of PV, maybe that is what they had in stock, maybe it made more sense with your panel configuration, in the end this was probably only a $200-300 more in actual cost. The Solar AC rating of 9.8kW is likely the maximum calculated amount based on the your 10.8kW solar panel orientations. The 11.88kW export limit is likely what PG&E ultimately communicated back as that amount plus a margin factor. I don't think there is any published information on how this is calculated.
Note: Earlier I said that my site export limit was 7.16kW, but it is actually 7.82kW or 3.5% higher than my 7.556kW Solar CEC-AC rating.
aesculus
Still Trying to Figure This All Out
Interesting observations from you all about this new graduated dicharge for VPP events. I did not participate this year because I did not like spending my last hour running off of the grid during an event after it pulled all my power down in the first two hours.
The other thing I did not see reported is did the PWs get charged during off peak via the grid to 100% prior to the event like they did last year?
The other thing I did not see reported is did the PWs get charged during off peak via the grid to 100% prior to the event like they did last year?
You are reading this correctly, but the detail is that it is on an hour-by-hour basis, not over the whole period. You can set your reserve to 100% for the first hours of the VPP event and then set it back down when you usually stop exporting.
That might be a very interesting trick to use, but there isn't anything in the ELRP/VPP documentation that says that the baseline calculation is done this way. I couldn't reconcile my 2022 VPP numbers with the Tesla check that I received so I tried this with my data and it still didn't reconcile.
I am watching for this today. So far no grid charging of the PW pre-VPP. PW was down to 8% overnight.
Last year the VPP based grid charging didn't activate until it gets close (<2 hours) from the start time if the Powerwalls weren't at 100% and the algorithm determine that solar was unlikely to get it there in time.
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