Annual (temporary) goodbye to grid power?

[GregBallantyne]

My solar system started operation on June 10 last year, so this is my first April with solar. March was great - I made as much as I used, but still drew grid power some days and sent power to the grid some days. April has been really good. On April 6, I drew 15.1 kwh from the grid. Since that day, I've not taken grid power and sent 285 kwh back to the grid - after filling PWs and charging my car to 80%. Other than wishing for a way to save those kwh for later without net metering (still in place in MD), I am planning on not drawing grid power until sometime in October and thinking that I'll not be billed for power until some time in November. We will see....
Any others saying a temporary goodbye to grid power?

 

[CWhite]

Sure is nice not getting a big bill anymore, isn’t it. We are lucky to have 1:1 net metering here. Just for fun I went off-grid for a month when I first got the system but that was it. Did not save me any money using the powerwalls at night. It has worked out well not cycling the batteries , after 7 years my first Powerwall still has 100% of its rated capacity.

 

[lodar]

Any others saying a temporary goodbye to grid power?

Yup. Been running “Self Powered” for this past week. Probably could have started earlier. Still sending excess power to the grid during peak.

We just had a cloudy period and had only one day where the batteries didn’t fully charge.

 

[GregBallantyne]

Yup. Been running “Self Powered” for this past week. Probably could have started earlier. Still sending excess power to the grid during peak.

We just had a cloudy period and had only one day where the batteries didn’t fully charge.

In my (continuing) 20 day stretch, there were two low generation days the PWs did not fill - 20.9 and 14.9 kwh days. I didn't charge the car those days, since I've been charging on excess solar only. Didn't have charge on excess solar capability until late last summer, so this year will be different.

 

[zƬesla]

We should get there once the mini-splits are switched off heat mode, hopefully in a few days. We're still getting the occasional below 20F night temps. For the past week though we've generated 597kWh, used 376kWh for the house, and drew 28kWh from the grid.

 

[CWhite]

Just curious, do you have a good net-metering plan there(or one at all)?

 

[Matt-FL]

I drew power from the grid on April 4th, haven't touched it since. Well, other than grid sync. The graph below shows my set of powerwalls charge rate (reserve set to 20%) - April 1st to today.

Here's my import vs export graph. This is a cumulative graph - blue line is export and purple line is import. Imported about 60kWh since April 1st, exported 930kWh.

 

[jboy210]

Interesting phrasing. For the past month or so we have not had any net draw except on days when it was cloudy. So I am happy we are connected to the grid, That connection gives us credits we use in the late fall and winter and gets us a live check when we send power back to the grid during the alerts. It was $300+ last year and only $200 or so this year. But surely a lot better than us sending them a check.

 

[GregBallantyne]

Interesting phrasing. For the past month or so we have not had any net draw except on days when it was cloudy. So I am happy we are connected to the grid, That connection gives us credits we use in the late fall and winter and gets us a live check when we send power back to the grid during the alerts. It was $300+ last year and only $200 or so this year. But surely a lot better than us sending them a check.

I'm looking at the date I stopped drawing grid power, with a perhaps aspirational expectation that I won't draw any for a self powering season that lasts until early October. In other words, no grid power thru the meter until October. I got on the good side of net draw for the month of March, but the last day I drew grid was April 6. It'll require attention, if I can make it.

 

[CWhite]

I am still trying to understand why you don’t want to draw from the grid. Of course it is our situation where we have net metering that makes it something we don’t need to do. I know many areas don’t have 1:1 net metering. Just wondering…

 

[ucmndd]

I do love April and May, plenty of sunshine and not hot enough yet to have to run the AC…

 

[lodar]

I am still trying to understand why you don’t want to draw from the grid. Of course it is our situation where we have net metering that makes it something we don’t need to do. I know many areas don’t have 1:1 net metering. Just wondering…

PG&E has “non-bypassable charges” that breaks the 1:1 nature of their so called “net metering”.

It is better for your home to directly consume its own power, rather than “banking” it with the grid.

Ideally, solar energy should go directly into powering the home. Excess goes to battery, and finally to the grid when there is nowhere else to go.

Tesla Time Based Control (TBC) relies on banking from the grid. Power is drawn from the grid overnight and in the morning while solar is dedicated to battery charging.

I find the algorithm is off, filling the battery too fast with solar, then dumping excess at off-peak rates which will never make up for the NBCs.

When you have a significant solar surplus, it is easier to use Self Powered mode and avoid any grid banking at all. In my case, my surplus then gets dumped to the grid at Peak. The batteries drain less during daylight that offsets low battery demand overnight while we sleep and the house is idle. So, there isn’t that much more wear on the batteries than TBC.

So, all positives with little downside.

 

[jboy210]

PG&E has “non-bypassable charges” that breaks the 1:1 nature of their so called “net metering”.

It is better for your home to directly consume its own power, rather than “banking” it with the grid.

Ideally, solar energy should go directly into powering the home. Excess goes to battery, and finally to the grid when there is nowhere else to go.

Tesla Time Based Control (TBC) relies on banking from the grid. Power is drawn from the grid overnight and in the morning while solar is dedicated to battery charging.

I find the algorithm is off, filling the battery too fast with solar, then dumping excess at off-peak rates which will never make up for the NBCs.

When you have a significant solar surplus, it is easier to use Self Powered mode and avoid any grid banking at all. In my case, my surplus then gets dumped to the grid at Peak. The batteries drain less during daylight that offsets low battery demand overnight while we sleep and the house is idle. So, there isn’t that much more wear on the batteries than TBC.

So, all positives with little downside.

What are the specifics of the NBCs for Nem 2 documented? I did not see good examples on the PGE site. Also, a bit concerned about wear on Powerwalls with Self-Powered and can't seem to find any data on that.

 

[lodar]

What are the specifics of the NBCs for Nem 2 documented? I did not see good examples on the PGE site.

Overall, PG&E are incentivized to downplay NBCs except where legally required to disclose. Search the following PG&E files for “bypass” to see how little is described.

https://www.pge.com/content/dam/pge/docs/account/billing-and-assistance/vnem-brochure.pdf

https://www.pge.com/content/dam/pge...ired-storage-billing-faq.pdf.coredownload.pdf

Here’s a footnote from the above PG&E PDF.

Note: Non-Bypassable charges are handled differently from generation
credits/charges because they cannot be reduced by solar credits, but they must also be paid.

There are plenty of sites that get more into the details:
UPDATED — The ultimate guide to NEM 2.0: non-bypassable charges explained

The primary change from NEM 1.0 to NEM 2.0 is that a small portion of the electric bill can no longer be offset by excess production. This component of the total rate is referred to as “non-bypassable charges.”

The portion of the bill that can’t be reversed and the amount the compensation is reduced by, comprise what are called non-bypassable charges.

The best analogy is a bank charging a service fee on every withdrawal. You deposit $100 but find you can only withdraw $99. And before you scoff at that, here is a credit card that started charging “cash advance” interest when you buy gift cards.

https://www.cbc.ca/news/gopublic/cibc-gift-card-fee-1.7171377

 

[lodar]

Also, a bit concerned about wear on Powerwalls with Self-Powered and can't seem to find any data on that.

Search these forums, there’s plenty of discussions on Powerwall battery wear. Factors like state-of-charge, temperature, charge rate, chemistry, etc…

The same way a car’s odometer is an approximation on its relative wear, you can look at how much your Powerwall charges every day. It’s harder to compare odometer readings between different cars and owners. But it is handy when comparing your own batteries against themselves.

I looked at how much my Powerwalls charge every day between TBC and Self Powered. They are in the same ballpark of low 20’s kWh. A bit more with Self Powered.

Adding a bit of my own anecdote, these batteries also have an aspect of “use it or lose it” to them as well. My 10 year old Model S’s battery died with only 80,000 miles on it. All that careful driving and micromanagement and it didn’t buy much more life on the battery. Compared to others who drove their Model S farther, harder, and supercharged all the time.

 

[CWhite]

I got the iPhone app and checked my 7 year old Powerwall and it still has 100% of its 13.5 kWh capacity. This agrees with what I see when my utility taps the battery for one of their events(suppose to pull 80% and that is a bit over 10.5)

In my case it seems that age doesn’t matter. I go thru less than 20 complete charge/recharge cycles a year. With our 1:1 net metering I just leave it at 100% backup.

We are lucky our utility still have this type of net metering

 

[GregBallantyne]

I am still trying to understand why you don’t want to draw from the grid. Of course it is our situation where we have net metering that makes it something we don’t need to do. I know many areas don’t have 1:1 net metering. Just wondering…

My top goal for going solar is energy security. Not drawing grid power demonstrates achievement of that goal. Of course, I don't mind seeing circumstances in which I know I could have self powered instead of drawing grid, but for a decision, but another goal is to operate in a manner that is positive for all - my household, others, and for grid operation. When I fill my batteries and send power back on the grid, it's never at the time when the grid needs it. That adds pressure to see the day come when net metering goes away. We still have it here, but I know that day will come at some point.

 

[Tim-in-CA]

Yep, for me, I'm pretty much 100% self powered from April to October. I will sometimes pull some excess generation from the grid if I have to perform a more full charge for my EVs, but I try to charge them on excess solar before it is pushed to the grid when I can. I also will pull from the grid to recharge batteries after a VPP event is over and my PWs have been drained. But for the most part I am self sufficient 7 months.

 

[CWhite]

We are so lucky here to not have to worry about TOU or weird net metering rules. I just leave the PowerWalls in 100% backup mode. Seems like they will last a long time since we are not discharging them often. The best part is Portland General Electric(I cannot use their initials due to CA confusion) sends us a check every year for almost $300 which is about what our yearly natural gas bill is. Add in our 2 EV’s and we don’t have any real energy bills.

 

[Redhill_qik]

PG&E has “non-bypassable charges” that breaks the 1:1 nature of their so called “net metering”.

It is better for your home to directly consume its own power, rather than “banking” it with the grid.

The California NBCs are that big of a deal in my opinion. The current PG&E NBC rate is $0.03052/kWh and the Minimum Daily Charge, MDC, is $0.39167 which means that you can import 12.83 kWh/day or 4,684 kWh/year before you exceed the MDC amount if you are a net producer. If you are a net consumer then most of your NBCs are offset from the positive balance as they are already included. I am a net producer and have never paid more than MDCs and operating in Time Based Control.

Ideally, solar energy should go directly into powering the home. Excess goes to battery, and finally to the grid when there is nowhere else to go.

Tesla Time Based Control (TBC) relies on banking from the grid. Power is drawn from the grid overnight and in the morning while solar is dedicated to battery charging.

I find the algorithm is off, filling the battery too fast with solar, then dumping excess at off-peak rates which will never make up for the NBCs.

I use TBCs with custom utility rates that include the effect of NBCs and my solar first goes to the home load in the morning, then once solar generation exceeds that amount goes to recharging my Powerwalls and then to the grid and during the summer prioritizes export to grid and powerwall use during Peak.

Period	Winter Buy	Winter Sell	Summer Buy	Summer Sell
Off-Peak	$0.07	$0.06	$0.07	$0.06
Peak	$0.10	$0.09	$0.20	$0.22

When you have a significant solar surplus, it is easier to use Self Powered mode and avoid any grid banking at all. In my case, my surplus then gets dumped to the grid at Peak. The batteries drain less during daylight that offsets low battery demand overnight while we sleep and the house is idle. So, there isn’t that much more wear on the batteries than TBC.

So, all positives with little downside.

I would agree with using Self Powered mode for any NEM 3.0 customer, but for those on NEM2.0 and a net producer extensively using the Powerwall results in less exports to the grid and a lower Net Surplus Compensation amount at true-up.