Study on NEM 1.0 vs. NEM 2.0

[J.P.M.]

Can someone put down in really simple terms why it would matter if the POCO dices up the data in (net) hourly increments or nets out the monthly channel 1 data? I'm not getting this at all. It seems that if I'm pulling from the grid it's going to be in non-production hours. What am I missing? So no one thinks I'm a total dope I'm on year 4 of middle school math teaching (including algebra that is taught at the HS level) after a 30+ year career with Hughes/Boeing. It's it a nickel or dime thing or some serious numbers? The bulk of my NBCs are coming during my Super Off-Peak time when I'm running pool pump/washer-dryer/dishwasher/etc.

Anyone know when those DWR bonds expire? When they do then (assuming no change in billing...ha ha) my min bill should be like NEM1.

I'm ignorant of the term "channel 1" in the context you use it, but if you will be pulling from the grid during non PV production hours. You will also be pulling from the grid if, during PV production time(s), you are consuming more power than your PV system is producing.

Those DWR bonds expire all the time. New ones are usually issued/sold/called/etc. The DWR bond charge really never goes away, it just changes in value 1X in a while.

You may be beginning to understand the frustration and complication from lack of clear and complete explanation of how things work in the POCO rate realm.

IMO, this forum type format is limited as to its ability to do a good job of explaining the complexities of POCO policy and billing. That limitation is not made better or lessened by the POCO's seeming inability, intentional or otherwise, to give examples or direction that are clear and unambiguous, or don't generate more questions than answers

I believe I understand most of what SDG & E (my POCO) is doing and why, but I'm waiting for new rate sheets and hoping for some clarity and better understanding of the situation before I'll feel comfortable making suggestions to others about the state of affairs or what things may mean. Doing otherwise might well make me more of a counterproductive and POCO complicit hindrance than a help.

[oldguy]

I'm actually pretty comfortable with my bill for now. I think I have it correct (but channel 1 may be 2 and vice versa) but when I look at my smartmeter go through its commotions I see three data points on a rotating basis. The first one (which is over 60,000 for me) is number of kWh the grid has provided my home (channel 1), the second one is number of kWh I've sent to the grid (channel 2) and the third is the instantaneous flow...which if is negative I'm supplying more power than consuming...positive I'm consuming more than producing.

When I read through one of the CPUC documents SCE was arguing for applying NBCs only to channel 1 data as it would be the same as if they were to do the equivalent calculation on an hourly basis. I think that math is correct...but the CPUC citing (and I forget what) previous directive mandated they adhere to the letter of the law.

As for the DWR bonds...those were floated in 2002 as a result of the near meltdown of our grid (think Enron and its role) and DWR bought tons of power from out of state agencies to the tune of >$10 billion. I get that DWR may be floating bonds all the time, but I'd suggest these particular ones, and thus the ones that are part of our NBCs, have a limited duration as do all individually issued bonds.

The one disconnect I thought I had on my bill is they did not utilize the DWR bond portion of my bill while calculating the "bal of minimum charge" line item. That is because it's part of the delivery charges and thus caught up in "non-generation" charges in the PDF referenced in post above. I knew on NEM2 that I'd be subject to the minimum charge but wasn't looking to have the NBCs tacked on top of that...and in this case the DWR will be tacked on but is "only" going to be ~$2 as I tend to use ~my baseline allocation.

I wasn't the most likely candidate to go solar as I'd shrunk my bill from well over $200 to averaging out about $80...primarily with shifting power usage to super off peak on TOU. When SCE shifted to net 5 cents/kWh vs. 1 cent/KWh (if you hovered around your baseline credit and took account of the 9 cent/kWh x baseline start each month) I saw the writing on the wall...time to get panels up. I'm running only 3.45kW DC (Sunpower x 10 panels w/uinverters) and got a decent enough deal. Very small system...sized right for what we use.

[DrChaos]

Can someone put down in really simple terms why it would matter if the POCO dices up the data in (net) hourly increments or nets out the monthly channel 1 data?

The IOU (investor owned utilities) wanted it to be not net (all imports minus exports) but gross ('channel 1 imports'). The longer an interval you average over, the less the net import, and the less money the IOU takes in. So they would prefer the smallest interval, and customers prefer the longest interval.

Imagine you looked at all net imports if you added them all up second by second. That is virtually what the 'channel 1 data' measures.

Then look at them added up (exports minus imports) over the month---that will always be less than the previous. This is what NEM (no longer available) customers get. CPUC said that NEM-ST should be added up over a 'metered interval' which is one hour to 15 minutes depending on other normal rate tariff standard usage (apparently hour is typical residential, 15 min typical commercial). Utilities wanted total instantaneous imports.

I'm not getting this at all. It seems that if I'm pulling from the grid it's going to be in non-production hours. What am I missing?

When there are fluctuations between net imports and net exports. net imports over a time interval = max( sum(Import(t) - Export(t), for t in time_interval), 0)

time_interval = 1 month for NEM. time_interval could be 1 second or the shortest identifiable period the meter could register which might well be around 1/60th of a second. CPUC said 'normal billing interval' for NEM-ST.

It's it a nickel or dime thing or some serious numbers? The bulk of my NBCs are coming during my Super Off-Peak time when I'm running pool pump/washer-dryer/dishwasher/etc.

In your case, probably not. Difference between 1 hour and 1 month is big, but it seems that the 1 month is no longer possible. 1 hour vs instantaneous is less important but possible if you use power during the daytime production hours and fluctuate between net demand and net export. For instance if you have an A/C cycling on a hot, but cloudy day.

[oldguy]

DrChaos-still not getting it. Not really able to decode your max function above. The way I'm doing the math is if in one hour's time I use 1 kWh more than I consume it adds 1 kWh to the Ch 1 data. Speaking strictly about NEM2 as I get how NEM1 worked. I think of that Ch 1 data sort of as a diode in the sense that it only goes forward (i.e. increments)...never backwards. Maybe that's the confusion? It really doesn't matter how much I produce...when I consume more than I produce in any time increment (second, day, month) that sucker moves forward. So if I were to sum up the following "day in the life of":

midnight to 8 am: I use 5 kWh from the grid...Ch 1 increments 5 kWh
8 am to 5 pm on a cloudy day...so sometimes importing...Ch 1 increments by however much I import and whether or not 1 second, 1 hr, etc...doesn't matter..it just increments.
5 pm to midnight: I use 6 kWh from the grid...Ch 1 increments by 6 kWh

Maybe you think the internal resolution of the meter is 1 kWh? I found this for my smartmeter (Itron):
The maximum number of pulses is 65,535; therefore, the smallest pulse weight (PW) that can be used is:
PW, Min = 12,000 Wh / 65,535 = 0.18 Wh/Pulse

Is this maybe what you're getting at? Towards a rounding function, not in our favor?

I will try not to pester anyone more on this ; )

[sensij]

Is this maybe what you're getting at? Towards a rounding function, not in our favor?

I will try not to pester anyone more on this ; )

That is not what he is getting at. Imagine a a day in which your PV system produces a steady 3 kW from 11 am to 1 pm (not exactly realistic, but work with me).

If you had zero load, your import would be zero, and your export would 6 kWh (3kWh from 11 to 12, 3 kWh from 12 to 1).

Now, let's say we had a 4 kW load that we need to run for 1 hour (a top off charge on an EV?).

If we run that load from 12 to 1:
Import from 11-12 = 0, Export = 3 kWh
Import from 12-1 = 1 kWh, Export = 0 kWh
NBC's owed on 1 kWh.

If we run the load from 11:30-12:30, with hourly metering interval:
Import from 11-12 = 0, Export = 1 kWh
Import from 12-1 = 0, Export = 1 kWh
No NBC's

Now, if we run the load from 11:30-12:30, with 15 min metering interval:
Import from 11:00-11:15 = 0, Export = 0.75 kWh
Import from 11:15-11:30 = 0, Export = 0.75 kWh
Import from 11:30-11:45 = 0.25 kWh, Export = 0 kWh
Import from 11:45-12:00 = 0.25 kWh, Export = 0 kWh
Import from 12:00-12:15 = 0.25 kWh, Export = 0 kWh
Import from 12:15-12:30 = 0.25 kWh, Export = 0 kWh
Import from 12:30-12:45 = 0, Export = 0.75 kWh
Import from 12:45-1:00 = 0, Export = 0.75 kWh
NBC's owed on 1 kWh.

Do you see how the combination of interval time and timing of the load can charge whether or not NBC's are assessed?

[oldguy]

Ok...now I see. Akin to paying Jan mortgage in December, no? Bunch up the deductions. That said, does this not average out (I'm too tired to think harder than asking a question!)?

BTW, I think I'm back to thinking SCE has it wrong on minimum charges. If you look at what I wrote above...and namely I needed to scratch up a pre-solar bill (and TOU-D-A as I've been on that for 3 years). My wife found me one. In particular, at least the PPPC charge is part of the "delivery charges" and thus part of the "non-generation" charges mentioned in that CPUC decision. I suspect they all are and thus I believe all of the NBCs should be weighed against the minimum charge calculation...for those who don't have energy charges (i.e. they have energy credits). I'm working with someone who actually filed protest letters during the successor follow on formulations. He has sent an e-mail to one of the regulatory wonks at CPUC for clarification. He also thinks the other portion of the bill isn't being credited correctly...though only a buck or two off. Stay tuned...