SDG&E EV rates - EV-TOU-5 vs EV-TOU-2?

[Ampster]

Like J.P.M., I work with the 15 min interval data available from SDG&E.

.........

To make the data easy to handle I do some spreadsheet magic with look-up tables (with Excel's vlookup function), to assign the 15 min data to the proper TOU period. I then use Excel's Pivot Table capabilities to add everything up in a neat summary table. Once I get the proper monthly sums for the On-Peak, Off-Peak, Super Off-Peak and NBCs I apply the proper SDG&E cost for each component resulting in a match to the closest penny.

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I learned something too. I have been using Pivot Tables in Google Sheets but forgot about vlookup. That will make comparing different TOU rate periods easier. I am grandfathered into PG & E EV A rate for a while but it is good to know what my alternatives look like.

[J.P.M.]

I'm glad you could understand my rambling thru an explanation of how I handle the NBC data. Glad to have helped.

It only took me working thru the first 4 months of bills and banging my head against the keyboard when things didn't add up to figure out a method that matches SDG&E's values. The first two months of effort had me convinced that SDG&E was using a random number generator to get their NBC values. Now I have a better understanding, or at least a workable approximation, of what they are doing to get the monthly NBC value.

Understood.

You mentioned that you haven't tackled generation yet. When/if you do, holler back w/any questions. I'm believe I'm better at engineering design than spreadsheet design. I didn't examine any billing or rate schemes until after I'd gotten PV generation dialed in pretty good, and I didn't do that until after massaging the solar resource data I've been fiddling with since the mid '70's.

My goal for the bill generation was a necessary part of the overall goal to have a general method of being able to model a potential PV system's output and then optimize that PV system and its output for it's cost effectiveness and have the method be general enough to be applicable to any SDG & E residential customer given that user's pre, or estimated future gross electrical usage for SDG & E customers. To do that, I needed knowledge of SDG & E billing practices, schedules and how NEM works with all it's twists and turns.

Up until the addition of tiered rate schemes laid over a TOU schedule, I've largely achieved that goal, but appreciate that nothing stays the same forever. The tech./engineering part of the PV is fun for me, but I'd say the time and frustration of learning what wound up being a lot more than I wanted about POCO billing and the time spent on it were not things I particularly enjoyed. But, paraphrasing what Gus McCrae said, I always like to get where I started out for. Sometimes, when I think about all of it and where it started for me, something Bob Seger wrote comes to mind: "Wish I didn't know now what I didn't know then".

Back on topic.

[DrChaos]

While I can get very close on a bill to a T.O.U. tariff that doesn't have a tiered rate laid over it, it's also quite likely that I'm under some incorrect assumptions or misunderstandings about how SDG & E handles billing under a T.O.U. tariff that does have a tiered rate laid over it and that makes my method of backing out the credit for tier one usage in any billing period simplistic and incorrect.

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I honestly look forward to your thoughts and Richard's as well. If you're so inclined post (and/or send to me) an entire bill with name, address and acct. # removed with your climate zone and whether or not you're an all electric user, along with your green button data for the period covered by that bill, and I'll figure it out by adding the option for tiered rate overlay for my T.O.U. billing method..

I/WE may need some mod cooperation for that one. (Mods: how about it ?)

Respectfully,

I've looked through this, but it doesn't help on the specific point, how to get the baseline credit with TOU (and solar producing in some TOU periods). I understand the NBC's take 15 minute data to compute and I don't bother.

http://regarchive.sdge.com/tm2/pdf/ELEC_ELEC-SCHEDS_TOU-DR.pdf

I think without tiered components (e.g. EV-TOU2) I got fairly close in my own calculations as well. Also the question of what the city taxes and doesn't is vague but those amounts aren't so big.

and this is the big one for NEM-ST

http://regarchive.sdge.com/tm2/pdf/ELEC_ELEC-SCHEDS_NEM-ST.pdf

here is the relevant texts in these.

a) Baseline Rates: If the customer is a net consumer over a billing period, the net kWh consumed shall be billed at the applicable baseline rates up to the billing period’s baseline allowance, with any excess kWh consumed billed at the applicable non-baseline rates charged other customers in the rate class. If the customer is a net generator over a billing period, the net kWh generated shall be valued at the applicable baseline rates up to the billing period’s baseline allowance, with any excess kWh generated valued at the applicable non-baseline rates charged other customers in the rate class. Any nonbypassable charges, as defined in Special Condition 1 of this schedule, shall be billed based on the kWhs consumed in each metered interval net of exports. b) Time-of-Use: If the customer is a net generator during any discrete time-of-use (TOU) period, the net kWh produced shall be valued at the appropriate TOU rates charged other customers under the same OAS. If the customer is a net consumer during any discrete TOU period, the net kWh consumed shall be billed at the appropriate TOU rates charged other customers under the same OAS. Any nonbypassable charges, as defined in Special Condition 1 of this schedule, shall be billed based on the kWhs consumed in each metered interval net of exports.


That doesn't answer to me how to combine. It says 'If a customer is a net consumer during any TOU period" (my situation), "the net kWh consumed shall be billed at the appropriate TOU rates charged other customers under the same OAS".

Which to me, seems like I should be getting baseline credit up to my full baseline allowance if the net consumption is less (as it is). But I don't. There is no provision I see anywhere that baseline allowances are somehow subdivided among TOU periods, nobody with TOU without solar generation ever experiences: "oh your net baseline allowance for this period was maxed out and you cant take your underbaseline use in other periods to this one".


(a) makes sense to me, it's the core of net metering, that generation needs to be treated just like consumption except for the explicit NBC's (I'm fine with that).

[J.P.M.]

I've looked through this, but it doesn't help on the specific point, how to get the baseline credit with TOU (and solar producing in some TOU periods). I understand the NBC's take 15 minute data to compute and I don't bother.

http://regarchive.sdge.com/tm2/pdf/E...EDS_TOU-DR.pdf

I think without tiered components (e.g. EV-TOU2) I got fairly close in my own calculations as well. Also the question of what the city taxes and doesn't is vague but those amounts aren't so big.

and this is the big one for NEM-ST

http://regarchive.sdge.com/tm2/pdf/E...EDS_NEM-ST.pdf

here is the relevant texts in these.

a) Baseline Rates: If the customer is a net consumer over a billing period, the net kWh consumed shall be billed at the applicable baseline rates up to the billing period’s baseline allowance, with any excess kWh consumed billed at the applicable non-baseline rates charged other customers in the rate class. If the customer is a net generator over a billing period, the net kWh generated shall be valued at the applicable baseline rates up to the billing period’s baseline allowance, with any excess kWh generated valued at the applicable non-baseline rates charged other customers in the rate class. Any nonbypassable charges, as defined in Special Condition 1 of this schedule, shall be billed based on the kWhs consumed in each metered interval net of exports. b) Time-of-Use: If the customer is a net generator during any discrete time-of-use (TOU) period, the net kWh produced shall be valued at the appropriate TOU rates charged other customers under the same OAS. If the customer is a net consumer during any discrete TOU period, the net kWh consumed shall be billed at the appropriate TOU rates charged other customers under the same OAS. Any nonbypassable charges, as defined in Special Condition 1 of this schedule, shall be billed based on the kWhs consumed in each metered interval net of exports.


That doesn't answer to me how to combine. It says 'If a customer is a net consumer during any TOU period" (my situation), "the net kWh consumed shall be billed at the appropriate TOU rates charged other customers under the same OAS".

Which to me, seems like I should be getting baseline credit up to my full baseline allowance if the net consumption is less (as it is). But I don't. There is no provision I see anywhere that baseline allowances are somehow subdivided among TOU periods, nobody with TOU without solar generation ever experiences: "oh your net baseline allowance for this period was maxed out and you cant take your underbaseline use in other periods to this one".


(a) makes sense to me, it's the core of net metering, that generation needs to be treated just like consumption except for the explicit NBC's (I'm fine with that).

The concept of Baseline Credit or Baseline amount, which is calculated the same way BTW, is one that runs through all SDG & E tariffs that use tiers to wholly or partially establish a per kWh rate.

A bit of background: The baseline amount concept started many years ago with the idea that electricity is a commodity that should be available in subsistence (relatively small) quantities to everyone at a relatively low rate, sort of "this is the amount of electricity you need for basic subsistence".

To your conundrum of how to get the size of a baseline amount for any billing period, first off, remember what I've written and warned about SDG & E not making any of this easy. Part of the blame goes to the PUC which is a bureaucracy run largely top down and by committee. The utility rate structures are as they are partially for the same reasons that some say a camel is a horse designed by a committee.

To reach your goal of getting a baseline credit (or usage allowance - calc'ed the same way), you will need to know/find several pieces of information and then run some numbers.
Start out knowing that a baseline amount for an SDG & E residential electric bill changes every billing period.

Next, see/download the billing cycle schedule from SDG & E. Google "SDG & E + billing cycle schedule". download it. Look at it. Study it. Get familiar with it.
Note that the number of billing days and dates for any billing cycle period do not follow the calendar year or any adjacent month length.
Also, the number of days for any billing period and for any billing cycle change every year.

Next go to your SDG & E bill to get your billing cycle. Your billing cycle will be found on P.2 of your bill near the top of the page on the right side of the line that has your meter number.
Go to the billing cycle schedule and match/find your billing cycle in the left most column. That's your billing schedule.

Next, you will need three pieces of information:
- Your climate zone
- Time of year, summer or winter.
- Type of service, gas and electric or all electric.

I don't know why your referenced tariffs didn't include the necessary information to enable you to get a baseline size. So, I (just now) went looking and discovered that for some probably nefarious reason, SDG & E has removed the table that shows basic daily allowance from most of their current tariffs. However, that table is still shown as part of SCHs TOU-DR1 on P.U.C. sheet # 32156 - E, item 15, and TOU-DR2 on P.U.C sheet # 32157 - E, item 15. I intend to print those sheets until I find out W.T.F. is going on with the disappearance.

You can also get the # of billing days for your current billing cycle from P.2 of your bill, but that won't do you any good for a yearly bill and it'll change next year anyway. For next month's calcs, relying on the bill for the # of billing days won't work.

I'll use how to get my first billing period baseline allowance for calendar 2020 as an example of what you need to do. Follow the bouncing ball.

I'm billing cycle 3.
See the billing cycle sheet and find the first billing date for 2020 for billing cycle 3 to be Jan 6, and for that cycle and billing period that there are 33 billing days in the billing cycle.
Go to the mentioned table that's with schedule TOU-DR1.
- I'm all electric.
- I'm in the inland climate zone.
- The season is winter.
Put those 3 things together on the table and find that my daily baseline allowance for that billing period is 14.6 kWh/day.
Multiply the 14.6 kWh/day by the 33 billing days in the billing period to get the baseline billing period allowance for that billing period: 14.6 * 33 = 547.8. round up to 548 kWh.
Repeat the process for each billing period in the billing cycle using the appropriate arguments.

Tier 1 usage or credit size for each billing period (and calc'ed the same way, BTW) == the baseline allowance * 1.3.

The disappearance of the table is a bit troubling to me as the daily baseline allowances have been dropping some since AB 327 and NEM 2.0 took hold and have changed a bit in the past before that.

Without the table, or some other way to know what the daily allowance is a priori, I and others who play with this crap will be S.O.L.

Take what you want of the above. Scrap the rest.

[J.P.M.]

On the NBC calculation, because I don't need to worry about it being on NEM 1.0, I forgot to mention how I checked the NBC calc I do for my DR-SES spreadsheets for new (non grandfathered) NEM 2.0 users.

So, FWIW:

Because I'm a bit slow on the draw a lot of the time, it took a while before it dawned on me that the answer or a way to check a spreadsheet (or any) calc done for NBC against what SDG & E thinks my NBC ought to be (and I believe is) right my nose - especially since I read and record all the POCO meter readings 1X/day about 20 minutes after I get up in the A.M.

I, and all I believe all NEM customers of SDG & E and most other CA POCOs for that matter, have meters that display a bunch of numbers. One of those numbers flashed on my meter's digital display is labeled "DEL". That's the # of kWh that have crossed the meter coming in from SDG& E since that meter was installed.

Now, according to everything I've seen and heard from the PUC, SDG & E and down to the solar vendors that I think have at least one eye and one balloon knot, all use language that can be paraphrased as something like: "Under NEM 2.0, new PV system owners will be charged NBC for every kWh that SDG & E sends (= delivers) to a new system owner." That's every kWh that crosses the meter from SDG & E's direction, that is "incoming" with the net +/- energy delivered or sent summed over every 15 minutes. That's not net over a billing period, but netted over every 15 minute period. That's one of the numbers I read/record every morning DUHH !?

So, if I read and record the meter "DEL" number at 23:59 hrs. local time just before one minute a new billing period starts and do that again one minute before the next billing period starts, and then subtract one from the other, I'll find how many kWh of my bill would get charged for NBC for the intervening period.

An example: My most recent billing covered the period 09/04/2019 to 10/03/2019.
Net usage for the period was -158 kWh. That agrees with my readings.
Tare number for my meter readings for the energy delivered for the billing period for the (09/04 - 10/03) billing period was 470 kWh.
Green button data sum of all positive (energy delivered) 15 minute kWh data for the same billing period was 466.595 kWh.
(FWIW, the same green button data shows I sent 576.66 kWh back to the POCO for the billing period. The system generated 806 kWh for the billing period , meaning ~ 806-577 = 229 kWh of system generation got used on site.)
I believe the small ~ 3 kWh discrepancy in the reading for delivered energy and the sum of the positive green button 15 minute data is explained by different times of when I read the meter to when the billing periods start and end. I'll take the small error and as this example may show, I believe summing all the positive values of the green button data is reflected in the sum of all the positive green button data. That (positive) sum is the amount of energy that is subject to NBC and what I would have been charged if I was a new (non grandfathered) NEM 2.0 customer.