Confused now, I’m drawing from the grid powerwall 3 at 100%. Tech told me that wouldn’t happen.

[LiBeRtAs]

NEM3.0 Time-Of-Use Electric Home E-ELEC

This is what I was afraid of, it’s off peak time and I’m using the air conditioner needing more than solar is generating and instead of using the power wall, it’s taking it from the grid.

I was pretty sure based on what people said that the very most PG&E will pay me since I’m brand new to this and on the worst version of it is four cents or I don’t know maybe eight cents per kW but at no time will anything I buy from them be less than what they pay me, right?

I know I can change it to self powered and stop it from happening, but the Tesla person yesterday guaranteed me that I would not take from the grid when I had power wall capability and that’s exactly what is happening. Anyone have experience with to tell me what’s happening, thanks?

He also said if I switch back and forth from self power to time-based control that the time-based control has to relearn everything that takes a couple of days is that sound right to everybody?

The other thing that confused me was, he said if I’m on self powered, I will not ever sell to PG&E, that when self powered. I’m unable to export to them, I had not known that that’s annoying.

And I’ll look this one up, but I don’t know if sell price is what I get when I sell it to them and buy price is what I pay them or in reverse. I don’t know.

If I am right that at no time will they pay me more than I pay them for a kilowatt then I would like for it to be set up that I export to them or whatever but I never used the grid unless my power wall is below the reserve amount. And I just looked at the graph and at no point during the 24 hours is the sell anywhere near as high as the Buy.

Do you only get charged for the amount from the grid that you’ve used that’s in excess of what you exported to them? The only way this makes sense is since I’m being paid eight cents and I have to pay them $.40 per kilowatt if I don’t pay for kilowatts other than those that exceed the amount I’ve sold to them in that day. Does that make sense? Do you understand what I’m saying in that having nothing to do with the cost of the kilowatt if I export 9 kW today and I import 8kW then I don’t pay for any of those eight regardless of what they cost and regardless of what they would pay me for those nine is that possible?

 

[arnolddeleon]

What is your backup reserve?

What mode are you in? self-powered or time based control? In either case, you shouldn't be pulling from grid unless your prices are set wrong (not appropriate for NEM 3.0)

What are the prices that you have set for buy and sell?

 

[LiBeRtAs]

What is your backup reserve?

What mode are you in? self-powered or time based control? In either case, you shouldn't be pulling from grid unless your prices are set wrong (not appropriate for NEM 3.0)

What are the prices that you have set for buy and sell?

BTW Just got off the phone with PG and E and they confirmed for me that at no time will they pay me equal or greater than what I have to pay them for energy so the Tesla Tech had it backwards but that's OK. I have my backup reserve set to 80%-20% reserve and just now having it on time based control while power wall stayed at 100 percent it drew from the grid which makes no sense to me and PG and E guy assured me that I don't want to do that that I want to change it back to self powered especially with NEM 3.0.

Yesterday is when I got PTO and Tesla had me change to Time Based control and I just now changed back to self powered but I will add screenshot next.

 

[LiBeRtAs]

Here it is, now Tesla also confirms that under NEM-3 and in my situation with the battery and sunshine, no reason to use timebase control. Actually got the same guy at Tesla who said he did have it backwards, as I thought. He was very nice about it, Tony. Nice guy and very helpful.

 

[arnolddeleon]

Yes, definitely, self-powered for NEM 3.0 unless you have so little battery that you need to play with time based controls to limit the discharge until peak.

I'm guessing your sell price is still wrong (I don't see it in the image) and you likely want your reserve way down unless you're super concerned about blackouts but it will cost you. Ideally you have enough battery to use up all your solar production because "selling" makes little sense.

I would set the reserve down to something like 5%. This assumes that the grid is pretty reliable and there are no critical reasons (e.g. medical equipment) if there was an overnight outage and you run out of battery. Ideally, your battery was sized to match the solar so that you have to sell a minimal amount to PG&E and that means you will be using the battery but that needs a lower reserve.

How many Powerwalls? How large is the PV? What is your typical daily consumption during the summer?

 

[LiBeRtAs]

Yes, definitely, self-powered for NEM 3.0 unless you have so little battery that you need to play with time based controls to limit the discharge until peak.

I'm guessing your sell price is still wrong (I don't see it in the image) and you likely want your reserve way down unless you're super concerned about blackouts but it will cost you. Ideally you have enough battery to use up all your solar production because "selling" makes little sense.

I would set the reserve down to something like 5%. This assumes that the grid is pretty reliable and there are no critical reasons (e.g. medical equipment) if there was an overnight outage and you run out of battery. Ideally, your battery was sized to match the solar so that you have to sell a minimal amount to PG&E and that means you will be using the battery but that needs a lower reserve.

How many Powerwalls? How large is the PV? What is your typical daily consumption during the summer?

Sell prices range from $.02-$.08, but the PG&E guy said most of the time it would be two cents. I only have one powerwall 3; have 10 panels for 4 kW, typical daily summer consumption 12 to 16 kWh if heavy air conditioning.

In addition to these terrible sell prices, they now charge all California solar customers a $15 a month fee.

I can actually use up to 23 kWh on a hot day actually. Usually no more than 20.

The past few months I have been operating and not exporting and unless it is a very cloudy day, I can get around the clock using solar and battery, I have not used the grid more than about 3 kWh total in several months.

 

[arnolddeleon]

A single Powerwall has roughly 13 kWh usable. Your PV system will on average produce around 16-20 kWh. During the summer it will be higher.

If you want a chance to use all your production and maximize the value of your solar production, you will need to use almost all your battery. Set you reserve to 10% or lower.

 

[arnolddeleon]

It likely didn't discharge earlier under "time based" because it didn't have enough history to "know" that it was safe to discharge before the peak window. Switching to self-consumption should prevent that. I'm not certain if you had your reserve set for 80% or 20%. I think you were saying it was set to 20%. This means you have about 10 kWh available for use. That might be just enough.

 

[LiBeRtAs]

It likely didn't discharge earlier under "time based" because it didn't have enough history to "know" that it was safe to discharge before the peak window. Switching to self-consumption should prevent that. I'm not certain if you had your reserve set for 80% or 20%. I think you were saying it was set to 20%. This means you have about 10 kWh available for use. That might be just enough.

Reserve 20%. The guy did say it takes 48 hrs to learn the time based, but I figure as long as my excess still gets sold to the grid, there is no reason not to use self powered. Yesterday TEsla guy said if on Self Powered you cant sell to the grid, PG&E said that is wrong. Hope it is.

 

[jjrandorin]

Reserve 20%. The guy did say it takes 48 hrs to learn the time based, but I figure as long as my excess still gets sold to the grid, there is no reason not to use self powered. Yesterday TEsla guy said if on Self Powered you cant sell to the grid, PG&E said that is wrong. Hope it is.

Any Excess power in self powered mode gets exported (sold) to the grid. "Excess" defined is any power that is not used by your home (or things connected to your home that use power, like car charging), or used to fill your powerwalls. At least, thats the way it works for me, and I have used exclusively self powered mode (no time of use mode) since my powerwalls were installed in Jan of 2020.

 

[arnolddeleon]

self-powered sells to grid. PG&E is correct. Now, I believe it is possible to configure a system for no export. That would be Tesla configuration, not a customer one.