Time of Use Bill Credits with SCE

[silversaver]

I ran a credit of 2,371 kWh for my solar electric billing year. I received my check from SCE for $104.58, as I have for the last two years since they were required to refund or carry forward the credits under Schwarzenegger. So producing more than you use will pay you back. But, I agree that you should use all you make as that is the best ROI for a solar home. My billing credit was over $300 on my SCE bill, but you only get credit for what it cost them to produce. Honestly, it seems fair to me. To effectively manage TOU, you must know how negative you are going during Peak and how positive you go during Off-Peak. Your electric bill from SCE has no clue what you generated or used; they only know the net difference. If you don't have a monitor that shows you generation, usage and net, you have no clue what is going on. mysolarstats.com is the only monitor company in the US, to my knowledge, that shows you your generation and usage by hour and by TOU periods, so you can then try to manage your usage to get the best TOU credits. SCE has changed their TOU time segments from when they began, so it is critical that you are able to track time in their TOU segments. TOU Peak, used to be 10 - 18:00, not it is 12-18:00. Two of the highest producing solar hours are 10 and 11 am. See http://mysolarstats.com/c/demo to see how tracking TOU works. Moving as much usage off of Peak is the way to go if you have solar.

I have found that it isn't hard to keep track of the energy you produced on SCE side. On your meter will tells you exactly how much energy you send to SCE (the "net" during solar production. you use part of your solar product during the day) and you can also get the number of energy you used from SCE. If you upload more, then you get credit. I plan my system to cover 100% of my electricity bill, so I'm not really worry about the standard D tier or TOU plan. Sounds to me if you plan your solar large enough to cover all your electricity, then TOU sounds like a good plan to have becasue you don't always turn on AC during peak time, only when need it.

[Volusiano]

Sounds to me if you plan your solar large enough to cover all your electricity, then TOU sounds like a good plan to have becasue you don't always turn on AC during peak time, only when need it.

If your system is large enough to cover all your electricity demand, you shouldn't even need to be on any TOU plan at all because the price of electricity becomes irrelevant. Whether it's $0.10/kwh or $1.00/kwh, you don't care because you're not drawing any extra energy from the grid as a whole. You're only drawing from your banked credits.

In situation where on-peak credits are stored in separate buckets than off-peak credits, you'd actually want to stay on the base plan instead of the TOU plan so that you'll only have to manage a single bucket of credits that can be used at any time.

[silversaver]

If your system is large enough to cover all your electricity demand, you shouldn't even need to be on any TOU plan at all because the price of electricity becomes irrelevant. Whether it's $0.10/kwh or $1.00/kwh, you don't care because you're not drawing any extra energy from the grid as a whole. You're only drawing from your banked credits.

In situation where on-peak credits are stored in separate buckets than off-peak credits, you'd actually want to stay on the base plan instead of the TOU plan so that you'll only have to manage a single bucket of credits that can be used at any time.

Thanks for the suggestion. I think it is a great advice. My estimate annual production is about 9973kWh and my annual usage is about 9000kWh, I guss I should stay in regular tier net metering instead of TOU plan.

[Ian S]

Thanks for the suggestion. I think it is a great advice. My estimate annual production is about 9973kWh and my annual usage is about 9000kWh, I guss I should stay in regular tier net metering instead of TOU plan.

Generally yes, but you might still be unable to offset all your usage: if you have one time of year when your electric use skyrockets and you have an annual true-up where your credit bank is zeroed out, then that annual true-up would have to be well before peak usage in order for you to bank enough credits to see you through the peak season. Otherwise you would not have the banked credits and would have to pay retail during the peak period then get post-peak overproduction paid back at the annual true-up at a minimal rate (typically avoided cost.)

Actually, I can see the utilities using these rate structure quirks to squeeze more money out of solar customers while keeping net metering in place. My utility, APS, has already taken a step in that direction by cutting the true-up compensation in half; it wouldn't surprise me to see them reduce that to zero.

[Volusiano]

Generally yes, but you might still be unable to offset all your usage: if you have one time of year when your electric use skyrockets and you have an annual true-up where your credit bank is zeroed out, then that annual true-up would have to be well before peak usage in order for you to bank enough credits to see you through the peak season. Otherwise you would not have the banked credits and would have to pay retail during the peak period then get post-peak overproduction paid back at the annual true-up at a minimal rate (typically avoided cost.)

Actually, I can see the utilities using these rate structure quirks to squeeze more money out of solar customers while keeping net metering in place. My utility, APS, has already taken a step in that direction by cutting the true-up compensation in half; it wouldn't surprise me to see them reduce that to zero.

We should already discount the true-up rate as insignificant anyway and not plan on any adequate return on it. We should only size the system for net zero metering but not more.

But the more effective game that the utility companies can play is to decide on when your annual true-up will take place. For example, my utility company SRP in AZ has already played this game by setting their annual true-up time at the end of April. This way, going into May which is when the highest energy consumption begins, you don't have any banked credit to offset against. So if you use more energy than you can generate in the first few months, you'd have to pay for it because you don't have any banked credit left to use for it, like Ian said.

Fortunately, usually May is also the best production month in the year, followed by June, July, August, etc. So at least during these months, increased demand should be met with increased production to match up evenly, hopefully. So if you truly can match up your demand with your production on a monthly basis, you should be OK.

By the way, Ian's utility, APS, still has the annual true-up set for the end of the calendar year in December. So in his case, there's a good 4 months of banked credit built-up going into the summer to offset any big spike of demand in the summer nicely. But then again, January, February and March are not so great production months anyway, so we don't know if you can bank a whole lot out of those months or not. In my case where heating is done with electric heat-pump, I wouldn't be able to bank a whole lot. But for people who has gas heating, they can probably bank more electric credits before going into the summer.

My utility company SRP provides daily report of energy usage for my household against the daily solar production. Although I only get a combined reading, so I can't tell exactly how much I use vs how much my solar system makes everyday, the daily combined reading is good enough to help me track whether I'm beginning to get into a deficit or not on a daily basis, so that I can make adjustment to my conservation in time (maybe turn the thermostat up a degree or two) to offset any deficit and ensure that I come out of the month without any deficit. When you already have lots of banked credits, daily tracking is not necessary. But when you don't have banked credits and demand vs supply is tight, daily tracking can be very helpful. I find this daily report of combined usage/production reading very helpful for me and I do track it everyday even if I don't need to, just for kick.

[Ian S]

But the more effective game that the utility companies can play is to decide on when your annual true-up will take place. For example, my utility company SRP in AZ has already played this game by setting their annual true-up time at the end of April. This way, going into May which is when the highest energy consumption begins, you don't have any banked credit to offset against. So if you use more energy than you can generate in the first few months, you'd have to pay for it because you don't have any banked credit left to use for it, like Ian said.

Fortunately, usually May is also the best production month in the year, followed by June, July, August, etc. So at least during these months, increased demand should be met with increased production to match up evenly, hopefully. So if you truly can match up your demand with your production on a monthly basis, you should be OK.

By the way, Ian's utility, APS, still has the annual true-up set for the end of the calendar year in December. So in his case, there's a good 4 months of banked credit built-up going into the summer to offset any big spike of demand in the summer nicely. But then again, January, February and March are not so great production months anyway, so we don't know if you can bank a whole lot out of those months or not. In my case where heating is done with electric heat-pump, I wouldn't be able to bank a whole lot. But for people who has gas heating, they can probably bank more electric credits before going into the summer.

I hope APS isn't reading this thread! Actually, for me, production in March and April is as good as or exceeds that in July, August and September. I have gas heat so I do bank a lot of peak time energy prior to May.

[Volusiano]

I hope APS isn't reading this thread! Actually, for me, production in March and April is as good as or exceeds that in July, August and September. I have gas heat so I do bank a lot of peak time energy prior to May.

I assume that you probably have south facing panels which can explain better production in March and April vs July through September. I have west facing panels so that's why my PVWatts production estimate shows best production starting in May onward.

My brother has south facing panels with SRP and he reverted back to basic plan from his EZ3 TOU plan so he doesn't have to deal with different TOU credit buckets. He has gas heating and gas water heater, plus south facing panels, so he has a lot of excess credits during the winter time. Too bad he can't bank them for the summer...

[Ian S]

I assume that you probably have south facing panels which can explain better production in March and April vs July through September. I have west facing panels so that's why my PVWatts production estimate shows best production starting in May onward.

My brother has south facing panels with SRP and he reverted back to basic plan from his EZ3 TOU plan so he doesn't have to deal with different TOU credit buckets. He has gas heating and gas water heater, plus south facing panels, so he has a lot of excess credits during the winter time. Too bad he can't bank them for the summer...

Yes, south facing panels. If APS were to change true-up to April, I might have to abandon the TOU plan. Through April last year, I had banked 1000 kWh of on-peak and about 120 kWh off-peak. The excess on-peak generated in the fall amounted to about 335 kWh. That means about 12% of my production would be essentially given away to the utility on TOU. And it's mostly on-peak production costing nearly $0.30/kWh (when you factor in taxes) that I would have to purchase from APS.

[Volusiano]

Yes, south facing panels. If APS were to change true-up to April, I might have to abandon the TOU plan. Through April last year, I had banked 1000 kWh of on-peak and about 120 kWh off-peak. The excess on-peak generated in the fall amounted to about 335 kWh. That means about 12% of my production would be essentially given away to the utility on TOU. And it's mostly on-peak production costing nearly $0.30/kWh (when you factor in taxes) that I would have to purchase from APS.

SRP's on-peak time is different in the 6 months of summer (1-8pm weekdays) compared to the winter (5-9am 5-9pm weekdays). This is to the solar homeowner's advantage, I think, if they're on TOU plan, because your production is mostly during on-peak time in the summer (which is what you want because it's when you need to run AC the most), and your production is mostly during off-peak time in the winter, which is also what you want because you don't really have big energy demand (like AC) during on-peak winter time, so you want to get more off-peak credits to even more things out.

Besides, the SRP winter price difference between on-peak and off peak is minimal ($0.10 on-peak vs $0.07 off-peak), while the summer price difference is huge ($0.21 on-peak vs $0.07 off-peak). So even though they conveniently have their annual true-up at the end of April to their advantage, at least their on-peak times in the summer and winter are different enough to work out better for me.

The point is that the TOU timing and pricing is so different, even here in AZ between APS and SRP, and even inside the same utility company, they may have several different TOU offerings as well. So you need to take that into consideration hopefully well before you design and install your system to take advantage of the right TOU plan (or stick with basic plan) and even perhaps plan your panel orientation accordingly to maximize your ROI as well.

[Volusiano]

There is no way you can tell from SCE what you produced or used. You only see the NET from SCE. Both of their number they show are wrong. They have no idea what you have made. They only know the net, and that goes for your meter reading too. Only your solar system knows what you made, not Edison.

That's too bad. But from the perspective of just knowing where your production is relative to what your demand is, even just a monthly net reading would suffice to tell you what you need to know about whether you have achieved net zero metering or not.

[J.P.M.]

That's too bad. But from the perspective of just knowing where your production is relative to what your demand is, even just a monthly net reading would suffice to tell you what you need to know about whether you have achieved net zero metering or not.

Agreed. Being cynical about POCO's and also human nature in general, I'd suggest it's not in the POCO's best interest to do things in a way that would help consumers figure out how to use less of their product. Also, if I perceive I'm paying less for something (my monthly elec. bill), I believe my tendency is to be less frugal in my electric use -->> use more. That may also be something buried in the recesses of the POCO's logic. However, to the degree you trust the POCO meter, you can get a reasonable estimate of your daily use by checking/recording system production and POCO meter reading on a regular basis.

[bando]

There is no way you can tell from SCE what you produced or used. You only see the NET from SCE. Both of their number they show are wrong. They have no idea what you have made. They only know the net, and that goes for your meter reading too. Only your solar system knows what you made, not Edison.

that appears to be the same with SDGE. i was really bummed out because i think there IS some way they could do it - at first when i turned on my solar, for about 3 weeks when i logged into my SDGE account online it was still showing my daily usage as normal. and then i used locus to see how much i was generating.

but then all of a sudden SDGE went back and adjusted them all to NET numbers, so now i have no idea what i used other than just adding back what i produce. but it makes me think that the meter does somehow "know" what is used vs. generated, they just don't report it that way.

the smart meter has a bunch of screens and none of them make any sense to me. they also zero'd out my meter when i applied for Net metering (a few weeks before the system was actually on and running).

it's so confusing. and now i don't have to pay for electricity until Nov 2014 but i have to pay for gas so they created a new account number just for gas.

[bando]

No, the meter has no clue what you made or used, just NET. That is why we started our business, to get, track and report the numbers that most of us want. But, if you want to get the generation numbers manually, and then add them to the NET, you'll know what you used. Our monitor business does that for a running three year period and it is displayable to any smartphone or web enabled computer. It is not that I distrust the power company, its that they don't like losing the business and they really don't know the numbers that you want. The meter has no clue of generation values, just NET. You would have to install our equipment, but for $2 per month cost, you get hour by hour numbers of generation, usage and NET and all is broken down into TOU time segments for your power provider. Or you try to do it manually.

oh i see. i didn't realize you were in the business. that is certainly useful!

[J.P.M.]

that appears to be the same with SDGE. i was really bummed out because i think there IS some way they could do it - at first when i turned on my solar, for about 3 weeks when i logged into my SDGE account online it was still showing my daily usage as normal. and then i used locus to see how much i was generating.

but then all of a sudden SDGE went back and adjusted them all to NET numbers, so now i have no idea what i used other than just adding back what i produce. but it makes me think that the meter does somehow "know" what is used vs. generated, they just don't report it that way.

the smart meter has a bunch of screens and none of them make any sense to me. they also zero'd out my meter when i applied for Net metering (a few weeks before the system was actually on and running).

it's so confusing. and now i don't have to pay for electricity until Nov 2014 but i have to pay for gas so they created a new account number just for gas.

I don't seem to have a problem, assuming I trust my SDG & E meter and my system monitor. I read/record what the meter reading is every morning. Yesterday at 0625 hrs. the meter read 291 kWhrs. This A.M at 0650 hrs. the meter read 284 kWhrs. I subtract yesterday's reading from today's reading (291-284 = -7kWhrs.) I then add what my system monitor thinks my system produced during the same time period. The system monitor showed 23.13 kwhrs. produced. for daily usage I take the algebraic sum of the two #'s: (-7) + 23.13 = 16.13 = my daily use for that approx. 24 hr. period.
- The (-7) kWhrs. is excess generation. It's the equivalent of running the meter backwards. A positive reading would mean I used more than I generated for that period. I'm not on T.O.U, but that shouldn't affect the reading.
- The same method works for any time period long enough for the meter to turn over 1kWhr, or 5 min. for my monitor. I do the same thing for entire billing periods.
- the "meter reading" on my meter is the one that appears every other refresh on the meter. Refreshes are about every 4 sec. or so. The other stuff on the meter is useful - see the SDG & E website for some explanation. I bet most smart meters run about the same way.
- SDG & E also zeroed out my meter. They screwed it up 2X and reset 3x. I found the error during an A.M. reading as described above. PITA.
- Since system startup, by usage as recorded seems in line with historic usage for my current location - about 7 yrs. or so. Smart mater changeout was on 01/12/2010 and also didn't seem to produce any noticeable change in usage.
- Yesterday was about as good solar weather as we're likely to see. My own software predicted an output of 22.98 kWhrs. for my system if 01/07/2014 was a "clear day". Given some minor Nov.-Jan. late afternoon shading, I feel I'm reasonably accurate.

[Volusiano]

... now i don't have to pay for electricity until Nov 2014 ...

Whoa, what's up with that? That seems rather nice that you don't have to pay for electricity until Nov 2014? Did you size your system for net zero metering?