TOU for SCE in Southern California analysis

[Alisobob]

From now on, I'm just like Bob set my ACs in comfort zone and let them run!!!

Good thinking....

I've been very comfortable... especially during the night.

I still have about 50% of my stored credit left... aprox $175.

I'll make it through the heat, and just about net out at zero credits.

[silversaver]

Wow, Silversaver you have over $700 credit and are still net consumer. Impressive. Way to maximize that TOU! Makes me wonder if it will continue...

Trust me, I have really manage my usages in super off peak. I try not to use the ACs if it is not super hot. All of that for finding out the true benefit of TOU-D-A plan for solar owners (Southwest 245 deg facing arrays 7.1kW DC system). From now on, I'm just like Bob set my ACs in comfort zone and let them run!!!

Again, we don't know the future if TOU will be any different. This Summer is cooler than last Summer, lets see what happen later of year and see if those credits generated will be use up or not.

BTW, from July 14 to Aug 12th, my solar generated 1202kWh

[insaneoctane]

Wow, Silversaver you have over $700 credit and are still net consumer. Impressive. Way to maximize that TOU! Makes me wonder if it will continue...

[silversaver]

Quick comment/question for those following the TOU stuff, particularly for SCE TOU-D-A with the "baseline credit" thingy....
While the math is all there to prove/disprove this, sometimes just looking at things offers a unique perspective....that is what just happened to me when looking at this month's bill that just showed up:

If you notice, since I had a NET negative (I produced more than consumed), -126 kWh to be exact, I *paid* $13.04 for what is kinda supposed to be a credit on my bill. Now, the epiphany I had looking at this was that I could have used 126kWh during "super-peak" for FREE (or almost). Because I'm paying $0.10347/kWh due to my net production- had I used an extra 126 kWh during Super peak when energy costs ~$0.109/kWh, the "baseline credit" would have offset the cost and it would have effectively been free. I'll take it further, I think that not only could I use more to get my net usage to zero for free, but I think I could use even more, up to by baseline amount, during Super-peak for essentially free due to the "baseline credit" more or less completely offseting the cost during super-peak.

Do you believe this?

Thoughts/comments welcome....

Why not? That's the rule of game you had to follow. You need to utilizing the super off peak if you are on a budget size system and your solar system better facing between South to West. I have been maximizing super off peak for EVs charging and achieve great results. My solar facing SW245 and the annual output is less than South facing arrays, but it might be getting more credit than South facing arrays. Now, I can charge EV during off peak than wait for super off peak. My solar not just cover 100% usage, it also cover 2 EVs.

[sensij]

Do you believe this?

Thoughts/comments welcome....

Yes, this is correct, and it is supported by spreadsheet modelling. It is just another reason to *not* oversize an array, and instead aim for something less than 100% of consumption. The CPUC has mandated that the new TOU plans being considered for the default rate plan in 2019 include some kind of baseline credit, so expect to see more of this in the future.

[insaneoctane]

Quick comment/question for those following the TOU stuff, particularly for SCE TOU-D-A with the "baseline credit" thingy....
While the math is all there to prove/disprove this, sometimes just looking at things offers a unique perspective....that is what just happened to me when looking at this month's bill that just showed up:

If you notice, since I had a NET negative (I produced more than consumed), -126 kWh to be exact, I *paid* $13.04 for what is kinda supposed to be a credit on my bill. Now, the epiphany I had looking at this was that I could have used 126kWh during "super-peak" for FREE (or almost). Because I'm paying $0.10347/kWh due to my net production- had I used an extra 126 kWh during Super peak when energy costs ~$0.109/kWh, the "baseline credit" would have offset the cost and it would have effectively been free. I'll take it further, I think that not only could I use more to get my net usage to zero for free, but I think I could use even more, up to by baseline amount, during Super-peak for essentially free due to the "baseline credit" more or less completely offseting the cost during super-peak.

Do you believe this?

Thoughts/comments welcome....

[insaneoctane]

Dear Insaneoctane,
thanks a lot for your posting your calculations. short question, why do you adjust the generation every hour through this formula>
=IF(ABS(C17)<0.015,0,C17)
thanks =)

Sorry for that. It's round-off to make my life easier. My inverter pulls a small amount of electricity at night (<.015 watts) and rather than have my solar show that small amount of reverse flow, I found it easier to look at 0 at night. Although you could argue my numbers are off by a smidge, it's worth it for simplicity of seeing -zero- when the array is not producing.

[sensij]

Dear Insaneoctane,
thanks a lot for your posting your calculations. short question, why do you adjust the generation every hour through this formula>
=IF(ABS(C17)<0.015,0,C17)
thanks =)

NREL's system advisor model reports negative generation over night in an attempt to show consumption of the inverter, resulting in negative number in its output. However, if within the spreadsheet, you want to scale the generation (testing a 3 kW system vs a 4 kW system, for example), the overnight values shouldn't be scaled, and a formula is necessary to account for that. InsaneOctane chose to zero those values out, instead. If you use PVWatts for your generation model, no negative values are included and that forumla is not necessary.

If you are in SCE territory, I made some modifications to his spreadsheet to account for daylight savings time, among a few other fixes. A dropbox link to it is here:

https://www.dropbox.com/s/9v7bogsz5rzdr11/SCE_TOU_JES_updated.xlsm?dl=0

[reworld]

Dear Insaneoctane,
thanks a lot for your posting your calculations. short question, why do you adjust the generation every hour through this formula>
=IF(ABS(C17)<0.015,0,C17)
thanks =)

Wow, my head has been rolling on this one. I followed your link to the Tesla forum and implemented the math the way miimura was suggesting as a starting point, but I had serious reservations about negative baseline percentages. Then when I returned here to status things, I see you've found more clarification and it makes more sense to me. I've adjusted the TOU-T to match the logic you last presented and it does make the TOU-T more appealing, but still not better than the TOU-D-A for me. I'm including a link if you want to see the TOU-D-T changes. The way the TOU-D-T requires month end data to calculate it's values (which are needed to arrive at month end values) seems almost circular, but if I just use the usage in kWh to calculate the month end data necessary to calculate % for baseline, then calculate the $'s I'm okay. I'll warn you that this new math does add a layer of complexity to the math in the spreadsheet to where it has noticeably slowed the calculation time down from near instant to a few seconds (depending on your hardware).

New TOU-D-T calcs:
Solar_TOU_Rev_M14_WIP.xlsm

Thanks again for hunting this understanding down, it's amazing how complicated the TOU-D-T baseline calcs really are comparatively speaking!

[J.P.M.]

According to his words and I do believed him (knowing the guy for 25+ yrs) The reform might increase his bill but still none sense for him aftering solar.

Understood. I should have used the satire font. I bet ~ 10 bucks a month on his bill is not a big part of his reality.

[silversaver]

Probably because he was getting quotes from companies like Solar City. My monthly bill was less than his, and with projections based on numbers very similar to what the rate reform actually passed, it is still possible to get a <10 year breakeven on NPV. However, prices $3.50 / W or higher don't really get it done... closer to $3.00 / W is where it started to make sense to me.

His average bills were at $30 to $40, so solar isn't making any sense.

[sensij]

According to his words and I do believed him (knowing the guy for 25+ yrs) The reform might increase his bill but still none sense for him aftering solar.

Probably because he was getting quotes from companies like Solar City. My monthly bill was less than his, and with projections based on numbers very similar to what the rate reform actually passed, it is still possible to get a <10 year breakeven on NPV. However, prices $3.50 / W or higher don't really get it done... closer to $3.00 / W is where it started to make sense to me.

[silversaver]

Different lifestyle/priorities, but if the $70/mo. is correct, perhaps interesting to note your neighbor's probably not dying or destitute from frugality. When/if you see him, you might want to convey the heads' up that rate reform is probably going to raise his bills.

According to his words and I do believed him (knowing the guy for 25+ yrs) The reform might increase his bill but still none sense for him aftering solar.

[J.P.M.]

I won't worry about opinions others had expressed. We're just here to share the results. I have a friend lives close to me has never pay over $70 per month in last 15 yrs to SCE (family of 4) and he thinks solar is completely waste of money when I told him I got solar.

Different lifestyle/priorities, but if the $70/mo. is correct, perhaps interesting to note your neighbor's probably not dying or destitute from frugality. When/if you see him, you might want to convey the heads' up that rate reform is probably going to raise his bills.

[silversaver]

I won't worry about opinions others had expressed. We're just here to share the results. I have a friend lives close to me has never pay over $70 per month in last 15 yrs to SCE (family of 4) and he thinks solar is completely waste of money when I told him I got solar.