DIY Self-Install in San Diego - 7.84 kW for < $1.30 / W

[CharlieEscCA]

Charlie: FWIW, I can't figure it out either, except maybe some holdover from prior billing period. Anything to be gleaned from the rest of the bill ?

No other info on the rest of the bill seems to point to an explaination. But the prior billing period was not TOU, so maybe something went wrong as part of the switch. I'll have to see what happens with next month's bill.

I've had pretty good luck calling SDG & E once I get someone knowledgeable on the other end. Haven't done it in a couple of years though.

LOL, I think I'll pass on calling SDG&E to ask "why weren't my non-bypassable charges higher last month"

[J.P.M.]

No other info on the rest of the bill seems to point to an explaination. But the prior billing period was not TOU, so maybe something went wrong as part of the switch. I'll have to see what happens with next month's bill.


LOL, I think I'll pass on calling SDG&E to ask "why weren't my non-bypassable charges higher last month"

I believe I understand your meaning and probably feel similar, but if it's an error, they'll eventually find it anyway. Seems a potentially small thing at this time that, if/when it does go other way, might not be so small. An error is an error and will eventually be found/corrected. If not an error, communication could lead to better understanding of just WTF is going on.

[CharlieEscCA]

I believe I understand your meaning and probably feel similar, but if it's an error, they'll eventually find it anyway. Seems a potentially small thing at this time that, if/when it does go other way, might not be so small. An error is an error and will eventually be found/corrected. If not an error, communication could lead to better understanding of just WTF is going on.

I get what you are saying, but the SolarEdge website gives me a pretty good idea of import kWh. For example, my import was no more than 200 kWh last month. So even if every kWh had non reimbursable fees, we are only talking about $3.20, so, even if they come back and correct it, we are talking small change. But from my read of the tariff, it is net import for each day of each period, where period is peak or semi-peak or off-peak. I was expecting more than $0.10 and less than $3.20,

[sensij]

Here is the text:

All eligible customer-generators taking service under this schedule are responsible for paying nonbypassable charges which pursuant to D. 16-01-044 are defined as Public Purpose Program (PPP) charges, Nuclear Decommissioning (ND) charges, the Competition Transition Charge (CTC), and the Department of Water Resources Bond Charge (DWR-BC). These charges will be based on the kWhs consumed in each metered interval net of exports as defined in Special Condition 1 of this schedule, over the course of each monthly billing period.

and, from special conditon 1

f. Nonbypassable Charges: Pursuant to D. 16-01-044 are defined as Public Purpose Program (PPP) charges, Nuclear Decommissioning (ND) charges, the Competition Transition Charge (CTC), and the Department of Water Resources Bond Charge (DWR-BC). These shall be based upon the kWhs consumed in each metered interval net of exports, over the course of each monthly billing period.

A "metered interval" refers to each 15 minute interval of metering, as I understand it. So, in any 15 min in which energy is net consumed (overnight, for example, or any 15 min interval in which loads exceed what is generated), the net consumed energy in that interval is subject to the non-bypassable charge. That clearly does not agree with the bill that CharlieEscCA posted, so I think we need more data to figure out exactly what they are doing.

[J.P.M.]

Here is the text:



and, from special conditon 1



A "metered interval" refers to each 15 minute interval of metering, as I understand it. So, in any 15 min in which energy is only consumed (overnight), all of that energy is subject to the non-bypassable charge. That clearly does not agree with the bill that CharlieEscCA posted, so I think we need more data to figure out exactly what they are doing.

On your statement re: "...in any 15 min in which energy is only consumed (overnight), all of the energy is subject to non-bypassable charge.", I think that time periods are not restricted to overnight.

I think we need a bit more clarification to go with the more data part, not only to figure out what happened, but in a larger scope, why. Like I suggested, call them. Their billing is not infallible, they made a 110 kWh error in my billing when I got PTO, about 2 months after a meter changeout BTW, that error was in my favor and I got to keep it.

Given the current, and looking like general, confusion, there may be some interpretation we're all getting wrong. Small potatoes now - maybe not small in the future, like Charlie's (and probably a lot of other's) misunderstanding/misreading of T.O.U. time periods and effective dates. A different understanding of what looks like is going to happen may have led to a different decision.

one other point: I believe the "net of exports" would cover all time periods, not just overnight.

[sensij]

On your statement re: "...in any 15 min in which energy is only consumed (overnight), all of the energy is subject to non-bypassable charge.", I think that time periods are not restricted to overnight.

I think we need a bit more clarification to go with the more data part, not only to figure out what happened, but in a larger scope, why. Like I suggested, call them. Their billing is not infallible, they made a 110 kWh error in my billing when I got PTO, about 2 months after a meter changeout BTW, that error was in my favor and I got to keep it.

Given the current, and looking like general, confusion, there may be some interpretation we're all getting wrong. Small potatoes now - maybe not small in the future, like Charlie's (and probably a lot of other's) misunderstanding/misreading of T.O.U. time periods and effective dates. A different understanding of what looks like is going to happen may have led to a different decision.

one other point: I believe the "net of exports" would cover all time periods, not just overnight.

Yes, i meant overnight as an example. I'll fix that.

[J.P.M.]

Yes, i meant overnight as an example. I'll fix that.

Not a knock. Just sayin'.

[CharlieEscCA]

So I went back and relooked at my spreadsheet and got close to the June bill 6 kWh subject to NBC (non bypassable charges) by treating each complete day as a time period. In doing that, I came up with three days where I had a net import from the grid for the day, and those three days totaled 7.25 kWh.

Perhaps when the next bill comes, we'll get a chance to get a new set of data and perhaps better dial in better understanding of what grid usage has NBC applied.

[J.P.M.]

So I went back and relooked at my spreadsheet and got close to the June bill 6 kWh subject to NBC (non bypassable charges) by treating each complete day as a time period. In doing that, I came up with three days where I had a net import from the grid for the day, and those three days totaled 7.25 kWh.

Perhaps when the next bill comes, we'll get a chance to get a new set of data and perhaps better dial in better understanding of what grid usage has NBC applied.

Anything using 15 minute periods ?

[BackwoodsEE]

The inspector wanted to tag me for using a wire nut in the junction box on the ground wire going to the roof. I tried to explain that for the SolarEdge system, both the DC GEC and AC GEC can be satisfied with the single GEC from the inverter to the service panel, but he kept insisting that the EGC from the inverter to the roof also had to meet the unbroken (or irreversibly spliced, etc) requirement of the GEC. He eventually agreed to call a senior inspector / supervisor back at the office, who agreed that what I had done was ok. Close call, it could have gone either way. Re-pulling 85 ft of green wire would not have been fun, although I could probably have found another way to make the connection in that box, or one somewhat bigger.

I'm curious why your EMT conduit wouldn't have satisfied the requirement for a GEC from the inverter to the roof. I'm looking at NEC 250.118(4) and, more specifically, NEC 358.60: "EMT shall be permitted as an equipment grounding conductor."

[sensij]

I'm curious why your EMT conduit wouldn't have satisfied the requirement for a GEC from the inverter to the roof. I'm looking at NEC 250.118(4) and, more specifically, NEC 358.60: "EMT shall be permitted as an equipment grounding conductor."

In 2014 NEC, the DC GEC is the conductor from the inverter to the point of connection with the ground electrode system. Per 690.47(C)(3), that conductor can be run with the AC conductors and serve as both the DC GEC and AC EGC, but it needs to be unspliced or irreversibly spliced, and installed per 250.64(E), which requires the raceway also be bonded at both ends.

690.43(B) says an equipment grounding conductor (EGC) per 250.110 is required for the array, and 690.46 says that if is smaller than 6 AWG, it needs to comply with 250.120(C) for physical protection.

My inspector wanted to apply the requirements of 690.47 to my EGC, which is not correct. By his logic, the fact that my ground conductor had a wire nut violated the "irreversibly spliced" requirement of the GEC. Fortunately, his supervisor jumped in a supported me, and recognized that the ground between the array and inverter was just an EGC (in my case). I agree that it is technically correct that I could have left the ground conductor out entirely between the array and the inverter, and used only emt to serve as the EGC, but I like having the known good connection without worrying about what my emt couplings might do over time. I probably added some confusion by using ground bushings on that EMT, but based on my limited experience with City of San Diego inspectors, extra grounding is never a reason for rejection, while they are keyed up to look for too little grounding. 250.97 also sort of comes into play since the DC is over 250 V, narrowing down the list of allowable connection techniques for EMT so that electrical continuity is ensured, although if using commercial fittings installed properly, I think you'd be OK.

Your case may be a little different than mine. If you sink an electrode at the array, or by virtue of how it is constructed, your ground mount becomes an electode, you may need to bond it to the GES on the AC side. That bond is usually made by burying a piece of solid 6 AWG copper along with your conduit from the remote ground to your house ground.

[sensij]

I hadn't been paying attention to my billing cycle, and didn't realize that PTO on the 19th was so close to the cycle end on the 25th. That works in my favor, I think, since the excess generation this last week works backwards to cover some of the month in which the system wasn't running, and the $50.28 balance for the rest will chip away at the minimum bill at true-up.

I had to make a few modifications to my bill tracking spreadsheet to incorporate the terms of NEM-ST. Here is the summary page: 1st bill.JPG








So... here is what we are looking at (mostly consistent with CharlieEscCA 's findings):

The starting point for me is a $200 credit, which is a new EV Climate Credit that SDG&E is paying out this year to EV owners who sign up. I got a bunch of emails from them about registering in the first half of the year, probably because I'm on the EV-TOU-2 tariff, and May 31 was the deadline. The credit could have ranged anywhere from $50 to $200 depending on how heavily subscribed it was, so apparently, sign-ups were on the light side this year. Maybe the requirement to provide an actual scan of the car's registration deterred some people, who knows? It is scheduled to be paid again each year from 2018-2020, with a new sign-up required each year. It is paid per car, so if we add an EV for my wife this year as planned, the credit will double for us next year (at whatever level it pays out). This is a cash-equivalent credit, which is why it shows up in the "payments" line.

That payments line doesn't show -200 though, it shows -192.14. The $7.86 difference comes from the non-bypassable charges (DWR-BC, PPP, ND, CTC), calculated against 452 kWh, which is the sum of the energy consumed in the Off peak and Super-Off peak periods netted over the month. This $7.86 value is not directly shown anywhere else on the bill, although when the appropriate line items in the "breakdown of electric charges" are summed, it gives the same number. It appears, then, that the "metered interval" over which NBC's are calculated is the net kWh for each of the TOU periods within the billing month, not netted over each 15 min period. If it was netted over each 15 minutes, it would have been higher. Both the off-peak and peak periods have a mix of 15 min intervals with net generation and other intervals with net consumption, so if NBC's were calculated against each 15 min, the total would have been greater than the total coming from the net across the entire period. By putting this charge is the "additional charges" line, it takes it out of the NEM calculations, satisfying the requirement that it can not be offset by NEM credits.

The NEM charges section comes from the sum of:
UDC rates, excluding non-bypassable charges, calculated against any TOU period showing net consumption.
EEEC rates, calculated against any TOU period showing net consumption.
Taxes and fees, as shown in that section of the bill (I can walk through those calculations separately, if needed, they haven't changed).

The NEM Credits section (applied credits + change in remaining credits) comes from the sum of:
UDC rates, *including* non-bypassable charge components, calculated against any TOU period showing net generation.
DWR-BC rates, calculated against any TOU period showing net generation.
EEEC rates, calculated against any TOU period showing net generation.
Credits for taxes and fees, calculated the same as the charges, except against the credit components.

In my case, I fully consumed the NEM credits this month, so there is no carry-forward. If the NEM credits had exceeded NEM charges, the difference would have been added to the Remaining Credits column.

Combined with what CharlieEscCA showed us in his bill, where the extra amount paid for NBC's counted towards the minimum bill for the month, the end result appears to be that NEM-ST will be essentially identical to NEM 1.0 billing for me, and perhaps many others who have enough offset to be assessed the minimum charge most months, and who consume less than 575 kWh combined (at current rates) in whatever periods are net consumption for the month.

CharlieEscCA , if you are reading this, can you post a screenshot of the same page of the bill that I showed?

[CharlieEscCA]

CharlieEscCA , if you are reading this, can you post a screenshot of the same page of the bill that I showed?

Here you go:
SDGE.PNG


I was negative in all periods, so not sure where the 6 kWh that were accessed with NBC's came from. Also, note the 5/9/2017 bill was not on a TOU rate, hence just a total kWh column entry.

Just a warning, if your account is set up for auto-pay, you have to cancel the auto payment sign up. I didn't cancel mine and that's where the payment above came from. I tried to get this back from SDGE now, but no dice. They said if I have a negative balance at the end of the year, I will get that back. It just all seems confusing to me, but I'll wait for true-up to see what happens (if house isn't sold by then -- depends on how the timeline for the new house build project works out).

[sensij]

Just a warning, if your account is set up for auto-pay, you have to cancel the auto payment sign up. I didn't cancel mine and that's where the payment above came from. I tried to get this back from SDGE now, but no dice. They said if I have a negative balance at the end of the year, I will get that back. It just all seems confusing to me, but I'll wait for true-up to see what happens (if house isn't sold by then -- depends on how the timeline for the new house build project works out).

Thanks. I had made that payment mistake on my first system, but it did all square up at true-up as promised. That reminds me to watch for my new gas bill too, now that it is split out separate I'll need to add the new account number to my online profile and setup auto-pay for that one.

If you sell the house and someone new takes over the account, it should automatically trigger a true-up. If you have excess NEM credits but not actual dollar credits, they get wiped out.

The potential difference between EV-TOU-2 and DR-SES with respect to NBC's is sort of interesting, even if the dollars don't add up to much. Super Off-Peak on EV-TOU-2 will always be a positive number, because no generation will occur in the 12:00 am - 5:00 am period. DR-SES can get negative numbers in all periods because the off-peak rate that applies overnight during the week is also applicable all weekend long, and the other two periods both naturally get exposure to good generating hours during the week.

Next month I will have negative total kWh, especially with some travel planned. I will be watching to see if that changes anything in how the NBC's are calculated for me.

For what it is worth, I think this month's bill would have been around $173 on EV-TOU-2. I haven't checked it against DR-SES or the DR tariff yet. My consumption was a bit higher than the previous couple months, but that might just be more miles on the EV.

[thejumpingsheep]

Thanks for the great info.

I just submitted a plan with the City of El Cajon (just outside of SD county line). I basically did the same steps while trying to keep things 100% DIY. I used the 30 day trial with solar design tool. I did not like their site plan so I just did my own very quickly using photoshop and the city track map. Took less than 30 minutes to do that and add the panels and label the electrical equipment. I am hoping they dont require and special rapid shutdown stuff with my design but I guess ill find out soon enough.

The hardest part for me so far is putting together the shopping list for the racking. I ended up going with mostly Unirac stuff, and quick mount flashing based on recommendations here. Unfortunately i probably will need to outsource the labor because I hurt my shoulders at the gym. I found an electrician who is going to do the work for about $3k.

Here is my setup:

5.7kW - 30 x 190w Topoint Panels
5kW SMA Inverter 3 MPPT
Unirac Racking (10 Panels will be tilted on top of flat car port)

I got the panels for about $2800 with freight. The inverter was about $1250 and along with the racking totaled about $2900 with freight. I figure the remaining stuff will run about $500 so Im looking at $6200 + whatever the permit will cost and $3k for labor for a grand total of about $1.70 ($9700/5700) per watt (STC) with labor. This seems inline with many other posts here as well as your own. If I didnt hurt my shoulders it would have run about $1.18 per Watt (STC)... stupid shoulders....