Because, in a nutshell, you you are not selling back to the utility if you have no solar. You would be charging at night, and running your home off powerwalls during peak, but not selling anything back to them during peak.
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How to charge powerwalls from grid with solar
- Thread starter coney27
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Because, in a nutshell, you you are not selling back to the utility if you have no solar. You would be charging at night, and running your home off powerwalls during peak, but not selling anything back to them during peak.
RKCRLR
Active Member
You're not allowed to feed back to the grid (as far as I know) but you (obviously) are allowed to charge the batteries and use the energy during peak hours.
But, if you have solar, what is wrong with using your batteries to power your home during peak periods, recharging your batteries from the grid once peak hours are over, and diverting all of your solar (but not battery power) to the grid during the day.
That would seem best for reducing peak power requirements on the grid and allowing you to have your batteries fully charged a greater portion of the time in case of power outages.
See post #8.
Without on-site generation, the only restriction is that your storage can't export to the grid. [While in theory charging from the grid and selling back to the grid later is providing a useful time shifting function, in practice residential tariffs are updated so slowly and with so much lag that the proper price signals aren't. If there were a rate plan in which your rate matched PG&E's spot rate, then I would think that it ought to be allowed, but that's purely hypothetical.]
Cheers, Wayne
You can have grid charging with solar as long as you dont want to send any energy back to the grid. Why not do that? I have my own beliefs around why no one wants to do that, but would be interested to hear others reason for wanting this.
Note. They dont "need" any more solar in CA so "to help the grid" isnt really a concern at this point.
aesculus
Still Trying to Figure This All Out
From what I understand in most markets (AZ as a special case excepted) you cannot do this because Tesla believes you are going to receive the federal solar tax credit which prohibits this scenario. They do make the exception for Storm Watch but that's it.
Perhaps you could prove to Tesla you were not going to apply for the tax credit but then they would have to put an exception in by hand to allow your system to behave that way. Probably not likely.
RKCRLR
Active Member
It's not just Tesla. It is PG&E's policy to not allow charging from the grid if you have solar.
Merrill
Merrill
Explain to me what is different about charging the powerwall (batteries) from the grid when I charge my Tesla from the grid.
Nosken
Active Member
It is PG&E-it doesn't;'t need to make sense and they can do whatever they want....until they unilaterally change things. My prime motivation for solar, was to buffer myself from PG&E charges. I am blaming PG&E, but the CPUC is complicit in the fleecing.
Merrill
Merrill
Yes, I agree I will not rant but Pacific Graft and Extortion is a monopoly out of control, why do I have to spend money to have power because they took their millions and did not invest in infrastructure maintenance.
Just curious, but is PGE's actual policy that it is not allowable to both charge from the grid with solar and also take advantage of the various solar net metering benefits they offer? I ask, because where I am, sometimes when I say something is "not allowed", it is more precise to say "the utility does not allow this for a customer taking advantage of net metering, and it would be foolish to give up net metering just to do this."
Utilities all have their own policies, so PGE may have something that does explicitly disallow charging from grid with solar, period. On the other hand, I find it kind of odd for a utility to say "you can't take energy from the grid for a device you own." But I do understand a utility saying "you can't take advantage of/abuse these special programs just to make/save more money." This could apply to things like taking advantage of net metering by adding a grid-charged battery or plugging other devices into an EV charging port that gets discounted rates.
If so, could a customer ask to not enroll in net metering, in which case they would get a wholesale rate (or nothing?) for all energy exported to the grid but could have both solar and grid-charged batteries?
Merrill
Merrill
What you need to understand is PG&E is a monopoly out of control run by incompetent people, they had what they call a flex power shut off because supposedly they could not supply enough power do to the extreme heat. Come to find out someone in the company pushed the wrong button, so again they have not invested in the future all the profit they make goes to the upper management and investors.
It is possible that PG&E hasn't caught up with the CPUC's requirements. But as I mentioned near the beginning of this thread, the requirement is that you either (a) charge the storage only from solar, but can discharge however and whenever you want or (b) charge whenever and however you want, but never discharge the battery in excess of your consumption.
The "no grid charging when solar is present" is foremost a limitation that Tesla is choosing to impose.
Cheers, Wayne
P.S. For an external reference, which includes a link to the CPUC decision:
CPUC Approves Energy Storage Net Metering
Cheers, Wayne
CPUC Approves Energy Storage Net Metering
Cheers, Wayne
CrazyRabbit
Active Member
they should still be configured to charge from solar; therefore, they can not charge from solar until the grid is reconnected.
Merrill
Merrill
It makes no sense to me that you cannot charge the Powerwalls from the grid, what happens when it’s winter and there is no sun, how do you charge the Powerwalls.
RKCRLR
Active Member
I called the PG&E Solar department and asked for clarification on this. Of course, they had no clue but said they will look into it and get back to me.
One thing I noticed, the decision addresses systems larger than 10 kW. I only have 2 PowerWalls. Does the decision apply to 10 kW or smaller systems?
This is speculation, but maybe 10kW and under already had the same leeways? Because I did a NEM Paired Storage interconnection agreement for (2) Powerwalls in July, 2018, as I read it, the only limitation was that the total power exported for the year should not exceed my solar generation for the year.
Cheers, Wayne
RKCRLR
Active Member
This the summary, it specifically says large net energy metering-eligible facilities:
"This decision partially grants a petition for modification of Decision (D.) 14-05-033, to allow large net energy metering-eligible facilities paired with energy storage using alternating or direct current configurations to take service under a Net Energy Metering Tariff. In D.14-05-033 the Commission declined to consider a possible pathway for direct current configurations, acknowledging such configurations may not be able to accommodate the metering equipment required by D.14-05-033. This decision approves non-metering, power controlbased options for ensuring net energy metering credit accrues only the net energy metering-eligible generation, as long as the control configuration is certified to a national standard or a utility-approved interim testing procedure. Power control-based options include the use of equipment, whether firmwarebased or software-based, to prevent the storage device from charging from the grid or to prevent the storage device from exporting to the grid. The decision denies an ex-post data verification option. The decision also adopts a means for measuring storage system size in direct current configurations, in order to determine whether size restrictions and metering requirements apply, as specified in Decision 14-05-033. The investor owned utilities shall submit advice letters to effectuate this modification. This proceeding remains open."
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