NEM-PS Annual True-Up Calculation [PG&E example]

[YRide]

I had not seen this version of a bill before, thanks for publishing it. This looks like a solar only NEM2 bill.

That makes sense, since it still doesn’t show as NEM2PS in my services section and no B&W. I assume this will update in 1-2mo.

I think the only factor added by storage is the limitation of NEM credits only to the amount of estimated solar production. The estimate is based on theoretical production for your system, based on panel count, orientation, inverter efficiency and sun position for each month. I'm not sure what it does about weather, but in my experience the estimate is far above actual exports.

I was if the impression that the max export was pretty close to the PVWatts modeling. Can anyone confirm?

This is due to a substantial amount of our solar being consumed rather than exported. If and when they get you the detailed bill, the export credit probably will not be a problem.

I thought it became an issue if you export solar during day at off peak and part peak + have many PW’s and do TOU arbitrage during peak. Which is kinda my case.

In addition to that, the detailed bill will show how your payments get accounted for across the various bundled rate categories, but this is only for their internal account. Hence the 16 pages...

Durning summer months with high solar production, NBC's dominate because the NEM charges are small or negative. But durning winter, your NEM charges will probably be positive, and considerably larger than the NBCs, so your turn-up will probably be based on NEM rather than NBCs. In either case, the monthly minimums will have already been paid, so that amount will be subtracted from the NEM or NBC basis to arrive at the true-up adjustment which you will owe on that true-up bill.

Ok, yes. But if I can generate lots of credits in summer and even fall at peak (TOU arbitrage with PW) then shouldn’t I be able to offset winter net consumption? I’ll anyways ensure that I never import at peak in winter just by having enough PW capacity.

 

[swedge]

I was if the impression that the max export was pretty close to the PVWatts modeling. Can anyone confirm?

I have run PVWatts and compared with PG&E. Very close, but not exact. I gather PG&E uses the month as defined by the customer's billing cycle, while pvwatts uses calendar months. Causes differences, especially around the equinoxes when day length is changing rapidly. Full year totals were very close.

My exports are always well below the PG&E estimate, even in winter when I'd doing some grid charging. With your lager storage capacity relative to your solar, you'll want to keep an eye on it.

 

[swedge]

Ok, yes. But if I can generate lots of credits in summer and even fall at peak (TOU arbitrage with PW) then shouldn’t I be able to offset winter net consumption? I’ll anyways ensure that I never import at peak in winter just by having enough PW capacity.

Yes, summer arbitrage will offset some of your winter production. But since it does not offset NBC's, those put a floor on how much offset you benefit from. The total you will pay through the entire year will be highest of three: the monthly minimum (paid monthly), the cumulative NBC, or the cumulative NEM credits. My guess is that in winter, your cumulative NEM charges will grow to the point where they exceed the NBCs. Time will tell...

 

[swedge]

@swedge didn't you have a theory somehow PGE didn't think I had a powerwall

Yes. Or maybe they still haven't processed your PW addition yet. Or maybe they are changing their procedures. Or maybe it is a mistake. Whatever it is, the explanation is simply "It is PG&E".

My current thinking on optimizing the true up is this: To the extent possible, try to get both NEM and NBC balances as close as possible to the MDC total. MDC is the monthly minimum you pay each month, and the total on NEM2A is around $140. NEM is aka Cumulative Energy Charges and Credits on the B/W bill, if you ever get one.

This is because the payment at true-up, the true-up adjustment, is calculated as the highest of NEM, NBC and MDC totals. You will have already paid the MDCs, so the adjustment is the largest of NEM-MDC (only if above 0), NBC-MDC, or MDC-MDC which is 0. Getting NEM and NBC close to MDC will make your total cost as close to MDC as possible. (This all changes radically for net exporters, lucky bastards! There is a thread on this.)

The NBCs run around 3.3¢ on every imported (not net!) kWh, so to stay below the MDC, you need to import less than 4,200 kWh over the year. NEM is driven up by imports and down by exports at the retail rates. (NBCs are included in import charges but not credited in exprort credits to NEM, so they are included in the NEM balance)

Self Powered reduces the imports, and hence the NBCs. Time Based setting reduced the NEM total by not importing during peak times. Export Everything shifts solar exports from off peak to peak, increasing the export credits to lower the NEM balance. Grid Charging allows charging even on short or cloudy days. Charging a car on off peak excess solar reduces the NBCs relative to car charging at night, a trick which PW now can automate.

Given that the solar production is what it is, and the same is true of our consumption, for us net importers, everything we export is later imported. So, EE increases NBCs while lowering NEM balance. Grid charging also increases NBCs. A Lower the Backup Reserve setting increases the amount of EE.

The tricky part is that summer months are very different from winter months, so the progress of the NEM and NBC balances does not tell us where they will be at true-up. This makes it hard to tell predict what settings to use. And it may be that different setting are best at different times of year. Your first full year true-up will let you fine-tune your settings for the next year.

All of this assumes that PG&E follows the tariffs and their own rules, which they sometimes don't.

 

[Redhill_qik]

@swedge does it look like I can use this instead of B&W to predict my EOY true up? It seems like I’m going to be a significant net consumer of kWh (mainly off peak as well as overall) but that my peak export credits will largely balance out on the $ perspective. So it looks like it’s gonna be mainly NBC’s.

I still can’t tell what my peak monthly allowable exports are. Need to make sure I don’t exceed that.

Circling back to this thread, the snippets that you posted are from a bill that covers your true-up month. How do these bill sections look for a "normal" month?

Reviewing these again, I think that these are the expected format for a solar account without ESS and a CCA (SJCE) for generation.

 

[Ampster]

My current thinking on optimizing the true up is this: To the extent possible, try to get both NEM and NBC balances as close as possible to the MDC total. MDC is the monthly minimum you pay each month, and the total on NEM2A is around $140.

I agree. I charge from excess solar during the day and use my batteries to avoid peak rates. I still have winter loads that exceed solar production so my total NBCs were $230 at True Up which covered my MDCs and that was all I paid because I also had a small NEM credit.

 

[YRide]

Circling back to this thread, the snippets that you posted are from a bill that covers your true-up month. How do these bill sections look for a "normal" month?

Reviewing these again, I think that these are the expected format for a solar account without ESS and a CCA (SJCE) for generation.

These were from my first bill post PTO. I haven’t had a true up yet (June 2024 will be first with PGE, apparently April 2025 for first one with SJCE CCA).

Every month since the one I posted (4 more) has show exactly the same. They just keep adding extra rows to the table.

It’s pretty intuitive to follow all the data in this format.

Is there a chance PGE is shifting to this new format?

Still haven’t heard of anyone post-PTO more recent then July 1, 2024 getting a B&W bill. And even @holeydonut lost the B&W, if I understand correctly, from an earlier PTO. @holeydonut does your bill now look like mine, on page 2 of this thread?

 

[YRide]

Yes. Or maybe they still haven't processed your PW addition yet. Or maybe they are changing their procedures. Or maybe it is a mistake. Whatever it is, the explanation is simply "It is PG&E".

My current thinking on optimizing the true up is this: To the extent possible, try to get both NEM and NBC balances as close as possible to the MDC total. MDC is the monthly minimum you pay each month, and the total on NEM2A is around $140. NEM is aka Cumulative Energy Charges and Credits on the B/W bill, if you ever get one.

This is because the payment at true-up, the true-up adjustment, is calculated as the highest of NEM, NBC and MDC totals. You will have already paid the MDCs, so the adjustment is the largest of NEM-MDC (only if above 0), NBC-MDC, or MDC-MDC which is 0. Getting NEM and NBC close to MDC will make your total cost as close to MDC as possible. (This all changes radically for net exporters, lucky bastards! There is a thread on this.)

The NBCs run around 3.3¢ on every imported (not net!) kWh, so to stay below the MDC, you need to import less than 4,200 kWh over the year. NEM is driven up by imports and down by exports at the retail rates. (NBCs are included in import charges but not credited in exprort credits to NEM, so they are included in the NEM balance)

Self Powered reduces the imports, and hence the NBCs. Time Based setting reduced the NEM total by not importing during peak times. Export Everything shifts solar exports from off peak to peak, increasing the export credits to lower the NEM balance. Grid Charging allows charging even on short or cloudy days. Charging a car on off peak excess solar reduces the NBCs relative to car charging at night, a trick which PW now can automate.

Given that the solar production is what it is, and the same is true of our consumption, for us net importers, everything we export is later imported. So, EE increases NBCs while lowering NEM balance. Grid charging also increases NBCs. A Lower the Backup Reserve setting increases the amount of EE.

The tricky part is that summer months are very different from winter months, so the progress of the NEM and NBC balances does not tell us where they will be at true-up. This makes it hard to tell predict what settings to use. And it may be that different setting are best at different times of year. Your first full year true-up will let you fine-tune your settings for the next year.

All of this assumes that PG&E follows the tariffs and their own rules, which they sometimes don't.

Now that I have 5 bills of data it is getting more interesting. NBC’s are a lot more then I anticipated (and so is the CCA charge) but still considering my circumstances (3EV’s, one with a long commute, AC, etc) it’s pretty good. Was paying almost $1k/mo before!

Since my true up cycle starts July and ends June, I’ve got a bit of catch up in NEM credits as the sun comes out next summer. After the first year I should have a better handle. Looking forward to the next 19!

 

[holeydonut]

These were from my first bill post PTO. I haven’t had a true up yet (June 2024 will be first with PGE, apparently April 2025 for first one with SJCE CCA).

Every month since the one I posted (4 more) has show exactly the same. They just keep adding extra rows to the table.

It’s pretty intuitive to follow all the data in this format.

Is there a chance PGE is shifting to this new format?

Still haven’t heard of anyone post-PTO more recent then July 1, 2024 getting a B&W bill. And even @holeydonut lost the B&W, if I understand correctly, from an earlier PTO. @holeydonut does your bill now look like mine, on page 2 of this thread?

Yeah my black and white bills are no longer available. I get extra detail on my blue-header normal bill though. I have no clue how to authenticate these values any more since I can't see the hour-by-rates broken out by each component of transmission, distribution, and all the things that @Redhill_qik got a PHD on.

 

[YRide]

Yeah my black and white bills are no longer available. I get extra detail on my blue-header normal bill though. I have no clue how to authenticate these values any more since I can't see the hour-by-rates broken out by each component of transmission, distribution, and all the things that @Redhill_qik got a PHD on.

View attachment 992480

View attachment 992481

Isn’t there another page that shows you the amount of kWh’s in each TOU bucket? Feels like this bill has all pieces of info one would need except for the allowable export limit per month.

 

[holeydonut]

Isn’t there another page that shows you the amount of kWh’s in each TOU bucket? Feels like this bill has all pieces of info one would need except for the allowable export limit per month.

The TOU buckets are there but not the unpacked detail that used to be in the telephone book sized black and white bill. Like you used to be able to cross multiply every portion of the unbundled TOU rates against import/export and actually back into the calculation that you would be billed. This ensured you were billed correctly. I actually got a refund one time because one month didn't seem to conform with all the other months in the way the bill was calculated (back when I had the black and white bill).

Edit: found my post about it:

Understanding PGE/SVCE electricity bills/TrueUP

Unlike most other companies PG&E is regulated and can only charge what was approved by the CPUC. They can't just slap any random fee on the bill and get away with line say your cable company might due. The blue bull is very straight forward and can be easily matched against the tariff rates...

teslamotorsclub.com

This new bill just assumes PG&E got the math right I guess. But this is why I wish @Redhill_qik or @miimura would get migrated to the new bill so he could prove/disprove that the new bill is accurate. I suck at life and suck at math, so I need someone smarter to do the maths.

 

[Redhill_qik]

Isn’t there another page that shows you the amount of kWh’s in each TOU bucket? Feels like this bill has all pieces of info one would need except for the allowable export limit per month.

The amount of kWh in each TOU bucket is not relevant to understanding your annual true-up amount. The billing info that @holeydonut posted earlier does show kWh per TOU period, so I don't understand why you are saying that you don't have this on your bill.

What is relevant are:

• Net Energy Charges for both PG&E and your CCA (TOU pricing is applicable)
• Your imported kWh to determine your total NBCs (TOU is not applicable)
• Your monthly/annual MDC charges ($10-$12/month or $130-140/year)
• Your total net kWh to determine if you are a net exported and owed Net Surplus Compensation if your Net Energy Charges are <$0

 

[YRide]

The amount of kWh in each TOU bucket is not relevant to understanding your annual true-up amount. The billing info that @holeydonut posted earlier does show kWh per TOU period, so I don't understand why you are saying that you don't have this on your bill.

What is relevant are:

• Net Energy Charges for both PG&E and your CCA (TOU pricing is applicable)
• Your imported kWh to determine your total NBCs (TOU is not applicable)
• Your monthly/annual MDC charges ($10-$12/month or $130-140/year)
• Your total net kWh to determine if you are a net exported and owed Net Surplus Compensation if your Net Energy Charges are <$0

Yes, the BB2 has all this. The only thing it does not seem to have is your maximum allowed exports in kWh for each month of the year.

 

[swedge]

Yes, the BB2 has all this. The only thing it does not seem to have is your maximum allowed exports in kWh for each month of the year.

Assuming your solar is what your installer told PG&E it is, I think the only way to exceed their estimated production would be to use a lot of Grid Charging and Export Everything. So maybe they found it wasn't worth the extra paper and postage.

On the other hand, I'm still getting B&W bills, so they have not done a mass conversion.

This new bill just assumes PG&E got the math right I guess.

Not a good assumption. My June true up B&W showed cumulative NEM higher than both NBCs and MDCs, but the adjustment was based on NBCs. They under billed me around $100, I don't recall the exact amount. But it proves that their calculations can be be erroneous. (This was discussed in another thread. I just wanted to know if it was an error in my true-up, or if it is a bug in their software in which case it might happen again....)

 

[Redhill_qik]

The TOU buckets are there but not the unpacked detail that used to be in the telephone book sized black and white bill. Like you used to be able to cross multiply every portion of the unbundled TOU rates against import/export and actually back into the calculation that you would be billed. This ensured you were billed correctly.

The unpacked/unbundled tariff rate components are more of problem in my opinion than a help, especially in the convoluted way that it is presented on the B&W bill with indeterminate rounding rules. The en

This new bill just assumes PG&E got the math right I guess. But this is why I wish @Redhill_qik or @miimura would get migrated to the new bill so he could prove/disprove that the new bill is accurate. I suck at life and suck at math, so I need someone smarter to do the maths.

It appears that you can do the same math with the bundled rates on the Blue bill to verify that the amounts are corrected for the month and then accumulated correctly for month-to-month. The one item that I didn't see captured by either @holeydonut or @YRide is the imported kWh per month and by period (for when the tariff rates change during the period) that is used to calculate the NBC amounts. I see the accumulated NBC, but not the monthly breakdown. Maybe this is elsewhere?

This is important as the net import/export numbers are aggregated by the hour, but the NBC imports are aggregated by 5 (or maybe 15) minute intervals. This leads to a higher NBC import number when it captures sporadic high current usage from equipment like an A/C condenser turning on for less than 5 minutes. Must months there is less than 10 kWh difference between hourly and the 5/15min interval, but during the summer I see increases of 40-80 kWh.

My PG&E true-up was on the last bill, so maybe I will get switched to the new format on my next bill?

 

[miimura]

I am waiting for my second bill since my most recent PTO. I have not seen any change to my B&W bill nor my blue bill yet. However, they changed the PG&E login flow on the web site and it would not load the login page in Chrome. I had to use Edge. I have similar issues with Quickbooks Online - I have to use Edge to avoid pulling my hair out in frustration.

 

[swedge]

The unpacked/unbundled tariff rate components are more of problem in my opinion than a help, especially in the convoluted way that it is presented on the B&W bill with indeterminate rounding rules. The en

It appears that you can do the same math with the bundled rates on the Blue bill to verify that the amounts are corrected for the month and then accumulated correctly for month-to-month. The one item that I didn't see captured by either @holeydonut or @YRide is the imported kWh per month and by period (for when the tariff rates change during the period) that is used to calculate the NBC amounts. I see the accumulated NBC, but not the monthly breakdown. Maybe this is elsewhere?

This is important as the net import/export numbers are aggregated by the hour, but the NBC imports are aggregated by 5 (or maybe 15) minute intervals. This leads to a higher NBC import number when it captures sporadic high current usage from equipment like an A/C condenser turning on for less than 5 minutes. Must months there is less than 10 kWh difference between hourly and the 5/15min interval, but during the summer I see increases of 40-80 kWh.

My PG&E true-up was on the last bill, so maybe I will get switched to the new format on my next bill?

A neighbor gave me a copy of his solar only, i.e. no storage NEM2 true-up bill. It looks very much like the donut's example above. The page for the current month does show imports and exports, but not by TOU period, just the totals, with three decimal places, i.e. to the single Watt-hour. This is under the heading "Service Information", along with the meter number, etc. It also says "Enrolled Programs: Net Energy Metering (NEM2)".

Interestingly, even on this true-up bill, the cumulative NBCs are not shown, only the single current month's amount. The NEM charges were higher, so the NBCs did not enter into the calculation, but that total would be indicative of total imports.

In contrast, my curent Blue and the B&W bill both call the rate schedule NEM2PS. Is it possible that a few NEM paired storage accounts have been billed as solar only, no storage? I'd guess that the rush to get under the NEM3 deadline may have swamped the billing crew, so recent PTOs might be way slow to work their way into the billing routine.

I think it took several months after my PTO before PG&E finally got me my coveted B&W bill, but they also wrongly switched me to a CCA, so I thought that confusion had entangled the entire area.

 

[holeydonut]

The unpacked/unbundled tariff rate components are more of problem in my opinion than a help, especially in the convoluted way that it is presented on the B&W bill with indeterminate rounding rules.

...

My PG&E true-up was on the last bill, so maybe I will get switched to the new format on my next bill?

Dude, how will you put your PHD in PG&E Bill Reading to use if they nix the black and white bill?

I hope you see the new style blue header bill with the graph in the next cycle. I think this view makes more sense for the average homeowner/user. Major gripe you'll probably have is how the NBC (each month and YTD) is calculated. The number just kind of appears each month, and similarly the detail supporting the YTD is something you'll need to keep track on your own.

For example, in my latest bill, the $186.64 is shown as the YTD NBC, and the most recent monthly NBC of $27.21 is itemized. But, there is no explanation to how $27.21 was calculated, and I would need to have 6 bills on hand to confirm the YTD was correct.

Oddly enough, they did include a table for each month YTD MDC as well as an explanation to how it was derived.


YTD total NEM true up (through 6 months in the NEM year):

YTD MDC Table:

In-period detail for the 11/08/2023 MDC:

In period detail for the 11/08/2023 NBC:

 

[YRide]

I am waiting for my second bill since my most recent PTO. I have not seen any change to my B&W bill nor my blue bill yet. However, they changed the PG&E login flow on the web site and it would not load the login page in Chrome. I had to use Edge. I have similar issues with Quickbooks Online - I have to use Edge to avoid pulling my hair out in frustration.

Might have go clear a cache in Chrome. I thought I saw they recommended that somewhere.

 

[YRide]

The unpacked/unbundled tariff rate components are more of problem in my opinion than a help, especially in the convoluted way that it is presented on the B&W bill with indeterminate rounding rules. The en

It appears that you can do the same math with the bundled rates on the Blue bill to verify that the amounts are corrected for the month and then accumulated correctly for month-to-month. The one item that I didn't see captured by either @holeydonut or @YRide is the imported kWh per month and by period (for when the tariff rates change during the period) that is used to calculate the NBC amounts. I see the accumulated NBC, but not the monthly breakdown. Maybe this is elsewhere?

This is important as the net import/export numbers are aggregated by the hour, but the NBC imports are aggregated by 5 (or maybe 15) minute intervals. This leads to a higher NBC import number when it captures sporadic high current usage from equipment like an A/C condenser turning on for less than 5 minutes. Must months there is less than 10 kWh difference between hourly and the 5/15min interval, but during the summer I see increases of 40-80 kWh.

My PG&E true-up was on the last bill, so maybe I will get switched to the new format on my next bill?

Imported power in kWh is there by billing period, but not by calendar month, nor by 5/15min interval (didn’t even know they did that for NBC).

The bill accounts for tariff changes (or in below case the summer/winter switch). That’s where I really came to understand the negative impact the winter tariffs have on my GC+EE TOU arbitrage.

I’m trying to think if NBC’s change with tariff changes? I think they do, it actually looks like NBC’s went down from 3.541¢/kWh to 3.271¢/kWh in Sep tariff change…does that align with your understanding?

Trying to understand NBC Net Usage Adjustment vs State Mandated Non-Bypassable charges. Is the NBCNUA pulling out something from the bundled rates because I’m on CCA?