TOU for SCE in Southern California analysis

[insaneoctane]

June update on my TOU-D-A plan. My bill ending 7/17 was -$110.93. It would have been ~-$36.68 on standard tiered (RATE-D), so TOU-D-A continues to rock for my household. I have increased my credit to a level to where I'm not sure if I should start using A/C more, quit worrying about running appliances like dishwasher and washing machine/dryer during peak hours.... I have a credit with SCE for $198.22 for my relevant period. This credit is giving me the opportunity to use A/C more than we ever have, I'm just not sure if I can start now, or wait for the hottest months coming (Aug/Sept). I've feeling using A/C more now is probably appropriate. I'm in new territory because TOU skews usage and because we are typically not A/C users much at all; but I'm now TOTALLY comfortable using A/C from 10pm to 8am (overnight) at $0.11/kWh. It's been interesting because I ran the A/C all night just recently and it doubled my kWh usage for the day (from 21kWh to 41kWh), but it was during Super off-peak and that is fine with me! The saga continues, thanks for listening!

[bcroe]

Conservation is good, I've done plenty. I know how many KWH a day each
major appliance uses. But like a video game, you can never actually "win".
Instead it evolves to diminishing returns.

Having invested in solar PV, its nice to know I can turn on anything I want,
and it won't show up on the electric bill. Having an older freezer here no
longer annoys me. No TOUs to deal with here, but haven't bought a KWH
in a year and a half. Propane refills are a once a year thing, at the lowest
summer prices.

Actually I have never even run the new heat pump to cool the house; guess
I should make sure that mode really does work. Opening some windows
during cool nights, the inside temperature has stayed in the 70s. Meanwhile
I'm running my neighbors air conditioners, helping the PoCo deal with the
peak, and getting credit for it. Till recently the PoCo used to double the KWH
rates June-July-August, for the AC they said. Never mind that my summer
usage didn't increase, but even that doesn't matter any more. Bruce Roe

[insaneoctane]

So far so good. ready for Summer heat

Have you done this before? Will you be able to use $600+ credit?

[silversaver]

Have you done this before? Will you be able to use $600+ credit?

My first year with TOU-D-A. I have use less AC in June. Start July to September, I'll be using more and more ACs.(2nd graph is before 2nd EV kick in. 1st EV kick in 7/14 and 2nd EV kick in 3/15) Charging 2 EVs with one level 2 charger is difficult (time wise), so I might have to start the charger on off peak hours to get more sleep hours..... Aug 2014, I still pull 600+kWh from SCE after 1200+kWh produced from solar. We did have a cooler 2015 Summer and hope it doesn't go too hot. Yes, I think I will use up the credit by end of ture up period.

[Alisobob]

I did not get solar to build credits. I got solar to use my A/C even more than normal, but not go broke doing it.


I still have about $180 in credits... I plan to use them all...

If I consume them.. so what?:

My annual SCE bill was right around $3400

If its $400 annually now , but I'm uber comfortable.... oh well.

[insaneoctane]

I'm not so sure I've been clear making my points. First, I have NO intention of keeping credits or making money. As a matter of fact, I'm pretty sure that's not even an option. Although I've build up a $200 credit with SCE, I'm not a net producer of energy and, therefore, would not be eligible for a cash payout. Even if I were eligible, it would be pennies on the dollars and that was never my intention with solar. But, now that I've gone to TOU-A, I'm finding I can build a credit even though I'm still a net consumer of energy because of *when* I make vs use energy. Anyway, I'm just trying to time using my credit properly, because if I don't use it up by the end of my yearly true up period it will just "go away" and that might be missed opportunities for me have used more A/C, leave my computer on and let it backup more often or at more convenient times, more dishwasher, dryer, washer etc. I'm just figuring this out. I think for my household and my weather, that a $200 credit is decent enough to relax a little. Nuff said.

[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.

[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]

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.

[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]

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.

[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.

[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!

[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

[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.