6kW system in Agoura Hills

[J.P.M.]

Some additional comment about staying/going back to strictly tiered rates:

A bit of background: Under many of the old CA NEM 1.0 T.O.U rate plans, a somewhat ironic situation developed whereby it was possible, indeed even relatively easy to game the time shifting of loads such that a system could be electrically sized to generate less than 100 % electrical usage offset without much inconvenience with respect to time shifting of loads, but still offset 100 % or more of a residential electric bill. If that happened it was often/usually the case for situations, for example, for folks who were gone all day and didn't fire up the A/C until they got home.

In other words, in many (sunnier) areas, the per kWh cost of the draw from the POCO could be made lower than the average per kWh value of the system generation in terms of the offset value of the genertion.

So, for example ONLY, a system that generated, say, 9,000 kWh/yr. might offset 10,000 kWh yr. of use and result in a near or ~= $0 annual bill.

A few very savvy folks saw that, ran some valid and accurate numbers, and those few usually saw that as a benefit for changing over from tiered rates to T.O.U. rates. Poster Sensij (who, BTW, has several posts to this thread but isn't around anymore) was one of the first to point that out. For many, it worked out that way.

Maybe those folks didn't consider that things in the billing/policy arena might change and that some head's up ball with respect to future rate policy and its uncertainty might be in order.

Anyway, at this time, some of those savings are still possible under NEM 1.0 grandfathered rates, but the value of the generation under current non grandfathered T.O.U rates and times is less than under the old T.O.U. rates and times, making system generation less valuable per kWh. While it's still possible, it's a lot tougher now to pull off the situation where <100 % generation offset will result in > or = 100 % of a bill using NEM 2.0 T.O.U. rates and times, particularly with higher min. daily charges, NBC, generally lower tier sizes and other changes.

When NEM 2.0 came along it changed a lot of things. One consequence of the changes: At the time of the shift to NEM 2.0, with the NEM 2.0 rates and times, the value of the PV generation for T.O.U. rates was ~ 25+ % less than it's value under NEM 1.0. Note: Current non grandfathered rates compared to current grandfathered rates are ~ 20+ % less cost effective, and even less valuable/cost effective if the current TOU rate has a tiered scheme laid over it which reduces the value of the tier one level generation for systems with a high offset %age. Those %ages are approx. but probably not far off for most rates/POCOs, in CA at least.

As always, calc'ing each annual bill for each different rate plan is a PITA, and doing such things with some accuracy needs a pretty thorough knowledge of the in/outs/hooks/landmines of POCO policies and how they affect the rates that are being compared. My experience is most folks don't want the hassle of doing the above, but to my experience only, given reasonably complete and accurate input, it produces reasonably close results when compared to existing bills.

All I think I might know with some certainty is that not using something like electricity (or wasting less of it) to accomplish a given task is more cost effective than getting more of it. Using less also provides me with the least impact from all these B.S. rate shenanigans.

Take it FWIW.

[Ampster]

Okay, that makes sense with that orientation of panels. Thanks for the explanation.

[gvl]

Yes the new TOU rate periods are anti solar. Depending on usage patterns they can be cost effective for EV owners and/or others with usage like pool pumps that can be scheduled when the rates are lowest. Did you use SCEs rate comparison tool? Are your pool pump and EV charging currently scheduled for times that the TOU rates are the lowest and/or did your spreadsheet take that into account?

I can see the new TOU periods can be cost effective vs. tiered for those without solar or with minimalistic solar systems if they can switch their loads to the off-peak periods. I suppose you could make a case for SW facing array as well. Mine is facing SE and this is how my later afternoon production looks on a "good day", and on such a day I usually have to run the AC during those hours. I downloaded my actual TOU-optimized usage from SCE for the last 12 months and wrote a little program to estimate the annual bill on different TOU rates, it does not consider the baseline credit or the holidays but it should be close enough. It is interesting that the "EV-friendly" TOU-D-PRIME rate turned out to be actually the worst of the bunch with solar, probably due the the largest on/of-peak price differential, daily charge and lack of baseline allocation credit.

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[Ampster]

... In some ways I regret not getting a larger system when I could.

You make a good case for those that are considering whether to oversize a system. Some times a slightly lower rate of return or longer initial payback is the trade off for a financial hedge against these kind of energy cost increases. It all depends on the risks one wants to take on.

[Ampster]

SCE tentatively confirmed that the domestic tiered plan is still open for NEM1.0 customers should they want to switch, so that's where I will likely end up as all the new TOU rates are clearly anti-solar. With the $3,000kwh annual grid usage most of it on tier 1 I'm looking at $600-700 annual bill, which beats my TOU estimates by several hundred dollars.

Yes the new TOU rate periods are anti solar. Depending on usage patterns they can be cost effective for EV owners and/or others with usage like pool pumps that can be scheduled when the rates are lowest. Did you use SCEs rate comparison tool? Are your pool pump and EV charging currently scheduled for times that the TOU rates are the lowest and/or did your spreadsheet take that into account?

[J.P.M.]

SCE tentatively confirmed that the domestic tiered plan is still open for NEM1.0 customers should they want to switch, so that's where I will likely end up as all the new TOU rates are clearly anti-solar. With the $3,000kwh annual grid usage most of it on tier 1 I'm looking at $600-700 annual bill, which beats my TOU estimates by several hundred dollars.

Understood.

If for no other reason than the POCOs no longer offer strictly tiered rates to new NEM customers leads me to believe it's not as profitable for them and so less expensive for users - so, I don't doubt what you write for one minute. Besides, I'm in a similar situation and tiered billing is more cost effective for me as well.

For most of the CA I.O.U. rate tariffs, if someone with a PV system and NEM 1.0 has a use pattern such that most of the residual usage above generation falls into tier 1 billing (if on tiered rates), the tier 1 per kWh charges are about the same/close to off peak rates for most of the T.O.U. rate tariffs. Among the several advantages there is that being on tiered rates you don't need to look at a clock before you turn on an appliance. Another advantage is that tier two rates on tiered billing are often quite a bit less that summer peak rates on T.O.U. tariffs.

Still, every situation is different and making general statements or taking them as gospel without running the numbers can lead to higher bills.

[gvl]

SCE tentatively confirmed that the domestic tiered plan is still open for NEM1.0 customers should they want to switch, so that's where I will likely end up as all the new TOU rates are clearly anti-solar. With the $3,000kwh annual grid usage most of it on tier 1 I'm looking at $600-700 annual bill, which beats my TOU estimates by several hundred dollars.

[J.P.M.]

Thanks J.P.M., you're a wealth of knowledge about solar and it surely benefited me when I installed my system in 5 years ago. I actually ended up with a 9kW system after all so this topic's title is not up to date. With 9kW your estimates seem to be right on the money here as well. 9kW at 80% offset worked pretty well for us up until now with an EV, I would end each NEM period with $100-200 in credits despite being a net consumer to the tune of 3,000kwh. If nothing else, I will consider the rate change to be an opportunity to find ways to further decrease the footprint.

You're welcome. As for the worth of what I might spout off about, opinions vary. I only suggest questioning, if only in your own mind, everything everyone - including and maybe particularly me - says until it makes sense to you

To sort of reiterate, my numbers are maybe one level above a SWAG.

Depending on if/how you time shift the loads, it's possible to reduce the net average price you pay the POCO per kWh to below the ave. per kWh $ value of what your system generates. It's just much harder to do with new user (non grandfathered) NEM 2.0 T.O.U. rates.

Perhaps interestingly, to the degree that time shifting of loads reduces the average amt. paid per kWh to the POCO happens, the PV system cost effectiveness improves, but not because of any improvements made in the system, but rather, because the difference between the value of the generated electricity and what you pay per kWh to the POCO increases.

Also and probably ironically, if initially designed for a load offset of < 100%, under a lot of load shifting, the system actually gets closer to a 100% $ offset. If initially designed for 100 % or greater offset, the system becomes more oversized from a billing perspective.

[gvl]

Thanks J.P.M., you're a wealth of knowledge about solar and it surely benefited me when I installed my system in 5 years ago. I actually ended up with a 9kW system after all so this topic's title is not up to date. With 9kW your estimates seem to be right on the money here as well. 9kW at 80% offset worked pretty well for us up until now with an EV, I would end each NEM period with $100-200 in credits despite being a net consumer to the tune of 3,000kwh. If nothing else, I will consider the rate change to be an opportunity to find ways to further decrease the footprint.

[J.P.M.]

Just ran some quick and dirty calculations based on my detailed usage for the last 12 months. Considering my usage patterns are going to stay the same I'm looking at about $1k annual cost bump because of the TOU rate switchover. I guess I can't complain too much as I had a good run from 2015 and the system mostly paid for itself by now, but I became spoiled by not having to worry about my energy bill, and this is going change. If SCE will let me switch to the tiered plan as a NEM 1.0 customer that may actually work better as my net annual grid energy usage is just about the same as my baseline allocation, but I suspect this won't be an option.

Changing back to a tiered rate may be a possibility, but a call to the POCO may be worth it. I'm w/ SDG & E, and aside from the trick that required users to positively and actively elect to stay on tiered rates or they got switched to T.O.U. rates w/PV users on tiered rates going to the T.O.U. rate for PV system owners, another dirty little trick I seem to remember that SDG & E plays on NEM 1.0 users and tiered rates is that those NEM 1.0 customers on tiered rates who chose or in the future choose to try a T.O.U. rate, and see how it goes and subsequently find out it/think it sucks, can only change to another T.O.U. rate, but not back to the old tiered rate. At this time, a tiered rate will be available for NEM 1.0 users who choose to stay on a tiered rate.

But, check w/ SCE for particulars with respect to getting back to tiered rates. I'm pretty familiar w/ SDG & E stuff, and somewhat but less familiar w/ other CA POCO details, but from what I read (and reading between the lines) on the SCE website, whether you're allowed to go back to tiered rates or not may depend on whether or not SCE considers tiered rates to be strictly "grandfathered" rates.

On your $1K est.: That seems to sort of fit with what I think I've seen in checking out the idea that the step from grandfathered rates to non-grandfathered rates 5 yrs. after PTO (but, and as an aside- and note - for SDG & E anyway, and I believe the other CA IOU's --- >>>>, in no case beyond 07/31/2022) decreases system cost effectiveness by ~ 20% - 25 % or so.

An example only: For the situation in zip 92026 where I am, every installed STC kW of an unshaded south facing, 20 deg. tilt array under DR-SES grandfathered rates will offset ~ $615/yr. of an electric bill. Using the non grandfathered rates that amount drops to ~ $485/yr. or ~ 79 % as much as under grandfathered rates.

I'm waiting for the questions and weeping/gnashing of teeth when the unexpected hammer drops on those currently on grandfathered rates but don't know what's going to happen.

Anyway, under NEM 2.0 grandfathered rates and DR-SES, an unshaded 6kW system around here with that orientation - provided it's not sized to overgenerate - will produce very approx. ~ (6.0 STC kW) * ($615/STC kW * yr) ~ $3,690/yr. or so to offset an electric bill.

The same system under the NEM 2.0 (non grandfathered) rates will produce ~ (6.0 STC kW) * ($485/STC kW * yr.) ~ $2,910/yr. to offset an electric bill or ~ $780/yr. less.

Your mileage will vary depending on location and POCO.

[gvl]

Just ran some quick and dirty calculations based on my detailed usage for the last 12 months. Considering my usage patterns are going to stay the same I'm looking at about $1k annual cost bump because of the TOU rate switchover. I guess I can't complain too much as I had a good run from 2015 and the system mostly paid for itself by now, but I became spoiled by not having to worry about my energy bill, and this is going change. If SCE will let me switch to the tiered plan as a NEM 1.0 customer that may actually work better as my net annual grid energy usage is just about the same as my baseline allocation, but I suspect this won't be an option.

[J.P.M.]

[QUOTE=loungelizard;n414350]

They're still doing super off peak rates but only in the winter from 8 AM to 4 PM. Coincidence that those times are the same as solar production? Odd that super off peak in the winter wouldn't be from, say, midnight to 6 AM.Hmmmm...

https://www.sce.com/residential/rate...ial-Rate-Plans/QUOTE]

There's nothing special about what a particular hourly rate is called. They could be called A,B,C,D,E & F and the bills and consequences would be unchanged.

Before NEM 2.0, that is, under NEM 1.0, peak summer T.O.U. rates - the only hourly rate that was really head & shoulders above the other hourly rates, both for summer and winter seasons were in effect6 from 0800 - 1600 civil time, weekdays. All other rates for all other times were relatively close in $$ value to one another, regardless of name.

Existing and qualifying NEM 1.0 customers got to keep some of the more generous T.O.U. rates under NEM 1.0 w/ "grandfathered" rates for up to 5 yrs. after PTO.

Under NEM 2.0, and with it the realigned T.O.U. times, new PV users must take T.O.U. rates of some sort.

The reality is that the new T.O.U. rates under NEM 2.0 as compared to the old NEM 1.0 T.O.U. rates in effect at the rollout made a given PV system about 22% to about 25% less cost effective than the same system operating under the old NEM 1.0 T.O.U. rates. Some of that is due to NBC's, but most of that reduction in system cost effectiveness was due to changing the billing schedule times of peak charges to later in the day - away from times of likely peak PV generation - and more in line with peak demand on the grid. There were some other changes with respect to lengths of sumer vs. winter seasons and a few other things, but overall, most of the loss of cost effectiveness is due to the shift in peak times away from peak PV generation times.

Rates and times are and have always been gerrymandered to maximize profit for the service provider. What happened when PV took off, as a result of distributed generation that the POCO had little control over (residential PV) , was that POCO revenue suffered due to politics and the darling of NEM, and, additionally, supply and demand got out of whack from that lack of control in ways that made life increasingly difficult for the POCO's to keep in whack.

[gvl]

You're right, I didn't even realize they called it super-off-peak. Speaking of adding insult to the injury... In some ways I regret not getting a larger system when I could.

[loungelizard]

They've eliminated super off peak and shifted on-peak to 4-9/5-8 depending on the plan. Not too many options in other words.

They're still doing super off peak rates but only in the winter from 8 AM to 4 PM. Coincidence that those times are the same as solar production? Odd that super off peak in the winter wouldn't be from, say, midnight to 6 AM.Hmmmm...

https://www.sce.com/residential/rates/Time-Of-Use-Residential-Rate-Plans

[gvl]

They've eliminated super off peak and shifted on-peak to 4-9/5-8 depending on the plan. Not too many options in other words.