SDG&E, Solar, Net Metering, and Time of Use 2 (TOU2)

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ttweed said:
philip said:
It sounds like with your over-production, you will owe the minimum charges, as you would need to purchase at least $120/year in energy to have them all refunded. If you overproduce (energy not dollars), then the approximate $.04/kWh production credit would offset minimum charges, however this isn't a cost effective use of an expensive PV system.
Well, this month was my 1-year account true-up with SDG&E. I ended up with an $8.80 credit. Net generation credits and CA Climate Credit completely cancelled out the $120 minimum charge adjustment, and gave me a net negative bill for the year. I'm a happy camper. I would have paid probably $1500-2000 for the year without solar, and my amortized cost of the system was $650 (plus maybe $250 in lost opportunity cost from paying $13K up front). It looks like free money from the sky to me.

TT
Are you on a TOU plan ? If so, I'll guess that part (perhaps most) of the reason you ended up with a small credit is TOU savings. The utility is paying you to shift consumption and it let's you arbitrage your solar production.

As it should be!
 
sub3marathonman said:
ttweed said:
Well, this month was my 1-year account true-up with SDG&E. I ended up with an $8.80 credit. Net generation credits and CA Climate Credit completely cancelled out the $120 minimum charge adjustment, and gave me a net negative bill for the year. I'm a happy camper.

TT

I'm not from California, but I am impressed!

I was wondering if you could itemize how you ended up with the $8.80 credit for the year? Also, you must be doing serious energy saving measures to have a 5.5kw system covering your usage. I'm thinking the stove/oven and water heater are gas?

Once again, very impressive!
I have 3.88 kW of panels I'm putting up next week that will cover my home's electricity and our ~ 16,000 of annual car miles ... and partially off-set some of our heating from NG.
 
sub3marathonman said:
I'm not from California, but I am impressed!

I was wondering if you could itemize how you ended up with the $8.80 credit for the year? Also, you must be doing serious energy saving measures to have a 5.5kw system covering your usage. I'm thinking the stove/oven and water heater are gas?

Once again, very impressive!

Yes, our little beach bungalow is largely powered by natural gas--the stove, water heater, clothes dryer, and space heater are all gas-fired. There is no A/C, since we live close to the ocean in a peculiar micro-climate that rarely gets uncomfortably hot, or radically cold. The house is post-WWII single-wall construction, with a shed roof (no attic), so it was not well-insulated originally. One of the first things I did when we moved in years ago was replace all the steel-frame windows with dual-pane vinyl sliders. Then when we had to replace the roof membrane, I had it built up with 1-1/2" Polyisocyanurate rigid foam insulation and that helped a lot. Our biggest electricity use is charging the Leaf, which is pretty much equal to our entire household electrical consumption each month.

SageBrush said:
Are you on a TOU plan ? If so, I'll guess that part (perhaps most) of the reason you ended up with a small credit is TOU savings. The utility is paying you to shift consumption and it let's you arbitrage your solar production.

As it should be!
Yes, we are on the "EVTOU2 Residential" rate schedule. Here is the detail from our NEM Energy summary on the true-up bill:

NEM%20Summary_zpsqvaixybw.jpg


Beside the $8.80 credit, I received a check for ~$30 from Sunrun yesterday because of their production guarantee under the PPA we signed. They promised our system would produce ~7750 Kwh this year and because of the unusually rainy winter we had here, it only produced ~7435 Kwh. The guarantee says that they will pay us ~$0,10/Kwh for any underproduction, and we get to keep any overproduction. A small windfall, but another bonus. As my wife likes to say in such situations, "I'll eat that," so we will be going to Duke's restaurant next week for happy hour, in all likelihood. :D

TT
 
BTW, all SDG&E customers with a Leaf should also apply for the $50 EV credit being offered as part of a statewide greenhouse gas reduction program administered by the California Air Resources Board:
http://www.sdge.com/clean-energy/electric-vehicle-climate-credit

There is another thread going on about it here:
http://www.mynissanleaf.com/viewtopic.php?p=485350#p485350

In that thread, Randy also mentions a new experimental rate schedule being introduced, TOU-DR-E3. That's the first I have heard of it. It looks quite complicated, and I don't know if it is "NEM eligible" or if it would offer any advantage for solar customers. Phillip has asked that question in the thread, and maybe Randy can answer that question for us there, or here?

TT
 
@ttweed,
My read of the true-up bill shows you have $622.60 of credits. What happens to them ?
I think you better start thinking of ways to use electricity. Perhaps free EV charging for your neighbors ? :mrgreen:

By the way, I spent many a Saturday at what used to be called Alligator point. It was our favorite spot to jump off into the ocean for SCUBA. Getting thrown back on to the rock like dead fish when we came back was a bit crazy because of the sharp molluscs but it make for great entertainment for the onlookers.
 
SageBrush said:
@ttweed,
My read of the true-up bill shows you have $622.60 of credits. What happens to them ?
I think you better start thinking of ways to use electricity. Perhaps free EV charging for your neighbors ? :mrgreen:

By the way, I spent many a Saturday at what used to be called Alligator point. It was our favorite spot to jump off into the ocean for SCUBA. Getting thrown back on to the rock like dead fish when we came back was a bit crazy because of the sharp molluscs but it make for great entertainment for the onlookers.
I'm still not sure of how to read the billing summary, since it's my first one, but I think the "credits" line shows excess generation in terms of dollars that would have been billed if it was used during the peak time of day on the TOU schedule, which is when the system is producing. But they don't pay you (or credit your account) according to that schedule if you don't use enough electricity to offset it. If you have excess generation, they only credit you with about $.04/Kwh, which is the wholesale cost of generation. I think that $622 credit got turned into the $(94.01) "Additional Charges/Payments" credit by this recalculation, but I could be wrong.

"Alligator Point" is a beautiful spot down by La Jolla Cove that is great for diving. Unfortunately, in the last decade it has been totally commandeered by sea lions and harbor seals, along with the Children's Pool around the corner to the south, polluting the water and menacing swimmers. I'm heading down there in a few minutes on my bike, to check out the annual La Jolla Concours event that is held in the park above it.

Cheers,
TT
 
@ttweed
I'm still not sure of how to read the billing summary, since it's my first one, but I think the "credits" line shows excess generation in terms of dollars that would have been billed if it was used during the peak time of day on the TOU schedule, which is when the system is producing. But they don't pay you (or credit your account) according to that schedule if you don't use enough electricity to offset it.
I think more likely that the credit is sum of the unused kWh multiplied by their respective values during the time of day they were produced. So a mixture of peak and shoulder rates.

That still sounds like quite a few kWh sent to the utility for 4 cents a kWh. I completely understand a POV that does not lose any sleep over these kWh since the overall deal is excellent and the kWh go towards offset of emissions by someone else. I just wanted to point out that you have a bucket available should you choose.
 
ttweed said:
I'm still not sure of how to read the billing summary, since it's my first one, but I think the "credits" line shows excess generation in terms of dollars that would have been billed if it was used during the peak time of day on the TOU schedule, which is when the system is producing. But they don't pay you (or credit your account) according to that schedule if you don't use enough electricity to offset it. If you have excess generation, they only credit you with about $.04/Kwh, which is the wholesale cost of generation. I think that $622 credit got turned into the $(94.01) "Additional Charges/Payments" credit by this recalculation, but I could be wrong.

These statements are not easy to read, but I spent quite a bit of time analyzing mine since SDG&E billed me incorrectly and I had to figure it all out to verify I was made whole.

The TOU generation credits you had left at true up was: $531.55 (91.05 of the 622.60 carried over from 02/2017 was used against the usage in 4/2016). You were charged the full minimum charge adjustment as well. So you could have used $651.64 more electricity with no difference in your final bill. You have no credit for excess usage, because you used more kWh from the grid than you sent (You imported a net of 603 kWh from the grid).

I can't tell what the 94.01 additional charges/payment is, but it is likely money that was overpaid at some point to SDG&E - you can check on some of your earlier bills - it is likely on them as well and has been carried forward.

It looks like your system is sized just right for your net usage to be near 0 kWh for the year. TOU causes it to be oversized from a financial perspective, but with TOU time periods shifting you will be in good shape. The talk at the PUC is a 5 year lock in on the current time periods for residential NET metering customers before they shift.

I don't see any reduce your use credits on your bill, you may want to see if you are signed up, there is no downside from doing so and you may very well earn some additional credits on your bill. I'm not certain that they will credit against the minimum charge however.
 
SageBrush said:
I think more likely that the credit is sum of the unused kWh multiplied by their respective values during the time of day they were produced. So a mixture of peak and shoulder rates.

That is correct.

SageBrush said:
That still sounds like quite a few kWh sent to the utility for 4 cents a kWh.

Since ttweed is a NET consumer of power, the excess "financial kWh" were sent back to the grid at 0 cents/kWh. Essential they could have used quite a bit more power at no change in there billing.
 
philip said:
SageBrush said:
That still sounds like quite a few kWh sent to the utility for 4 cents a kWh.

Since ttweed is a NET consumer of power, the excess "financial kWh" were sent back to the grid at 0 cents/kWh. Essential they could have used quite a bit more power at no change in there billing.

OK, once again, I'm not from California, but I'd appreciate a bit further explanation about this. :oops:

I understand that ttweed ended up using 600kwh over the year, so he is a NET consumer of power. I understand what has been said that much more power could have been used without any financial impact to ttweed.

So the credit of ttweed's kwh (@ $0.04/kwh) sent to the grid went to offset the minimum $120/year charge. I think I'm understanding that.

So why didn't ttweed get any further credit or payment for the other $550 of electricity (even @ $0.04/kwh) that was sent back? If the power company didn't get it from him, they would have had to purchase it somewhere else.

And what would have happened if ttweed used 700kwh less, and was not a NET consumer of power?

I will say, from my perspective, that the power company has a sweet deal there in this situation, as there was no usage at all during peak times, and the PV sent huge amounts, 2.5MW, of power back to the grid at the most critical times. Here in Florida, it is always being stated that PV customers are somehow taking advantage of the power company because the sun doesn't shine at night, but in my opinion it only matters if the sun is shining during peak periods, where by definition somebody with PV generation will use less, or even send back to the grid, as opposed to another customer who runs his dryer, A/C, and arc-welder during peak times because TOU rates are not the norm.
 
sub3marathonman said:
OK, once again, I'm not from California, but I'd appreciate a bit further explanation about this. :oops:

I understand that ttweed ended up using 600kwh over the year, so he is a NET consumer of power. I understand what has been said that much more power could have been used without any financial impact to ttweed.

So the credit of ttweed's kwh (@ $0.04/kwh) sent to the grid went to offset the minimum $120/year charge. I think I'm understanding that.

In California, we have the choice of time of use or tiered billing (for the Investor owned utilities anyways). If you are on TOU, then the utility tracks both the retail dollar amount of NET generation plus the energy usage amount. The only time you will receive the ~.04/kWh generation credit is if you are a NET producer over the true up period. The retail amount that is tracked can only be used against energy purchases in the same true up period - if you have a credit at true up, you lose it.

sub3marathonman said:
So why didn't ttweed get any further credit or payment for the other $550 of electricity (even @ $0.04/kwh) that was sent back? If the power company didn't get it from him, they would have had to purchase it somewhere else.

This is correct - he produced it and was not compensated for it in any way. So he could of had a smaller PV system and lowered his capital expense.

sub3marathonman said:
And what would have happened if ttweed used 700kwh less, and was not a NET consumer of power?

He would get a generation credit for the 97 kWh he over produced - ~$4.00

sub3marathonman said:
I will say, from my perspective, that the power company has a sweet deal there in this situation, as there was no usage at all during peak times, and the PV sent huge amounts, 2.5MW, of power back to the grid at the most critical times. Here in Florida, it is always being stated that PV customers are somehow taking advantage of the power company because the sun doesn't shine at night, but in my opinion it only matters if the sun is shining during peak periods, where by definition somebody with PV generation will use less, or even send back to the grid, as opposed to another customer who runs his dryer, A/C, and arc-welder during peak times because TOU rates are not the norm.

It is more complicated than that and depends on the time of the year.

In California, PV has pushed the peak into the afternoon/evenings. A lot of this has to do with utility-scale solar farms and lesser to residential rooftop PV. In fact, the grid-scale farms have to curtail production during the middle of the day at this time of the year due to over-production/low demand - yet at the same time residential NET metering customers are "selling" this power to the grid at peak rates. Residential installs do not have the capability to curtail production, so the utility "must take" the power generated from NET metering customers.

FWIW, the California IOUs have or are in the process of changing the peak times to the afternoon/evenings.

You can look at the current demand on the CA ISO page. If you scroll down to the NET demand chart, the green line shows what the traditional power plants are providing - look at the big dip in the chart in the middle of the day (for this time of year) - a lot of traditional plants have to go idle, which raises their net operating cost. Residential PV is "behind the meter" so it shows up as reduced demand on these charts. The solar shown is the utility scale plants.

http://www.caiso.com/Pages/TodaysOutlook.aspx
 
sub3marathonman said:
...
So the credit of ttweed's kwh (@ $0.04/kwh) sent to the grid went to offset the minimum $120/year charge. I think I'm understanding that.

So why didn't ttweed get any further credit or payment for the other $550 of electricity (even @ $0.04/kwh) that was sent back? If the power company didn't get it from him, they would have had to purchase it somewhere else.

...
The $0.04/kWh only comes into play if you are a net contributor of power. Under the net metering rules, that is the only way you ever get paid by the utility. It makes some sense. The TOU rates and net metering have more to do with incentivizing behavior than they do with economics. If it were economically based, a consumer would get credited (and reimbursed) at whatever wholesale rates were in effect at any given time. Instead net metering happens at retail rates, the trade-off being that you don't get reimbursed for overproduction at retail (or even really wholesale) rates.
 
Thanks for the help in understanding my true-up bill, you guys! I suppose I should call SDG&E and ask them to explain it all, but I'm happy with the overall result, regardless. Sunrun did seem to make a good estimate of our generation vs. usage, which they revised at the last minute, BTW. Our original design showed 19 panels for a 5 Kw system, and when they arrived for the installation, they installed 21 panels for a 5.5 Kw total. I think they must have reconsidered our peculiar micro-climate and upped the capacity in order to meet their power guarantee. As it turned out, the system cost me $2.36/watt, and they have to monitor, insure, and maintain it for 20 years, and pay me if it doesn't produce what they promised.

At any rate, it looks like I can maybe be less concerned about charging the Leaf only at Super Off-peak times, a practice which I have always been very diligent in maintaining? I guess I can feel free to charge it in the middle of the day if need be from now on, if I am ending up with a total cumulative credit which I didn't use and isn't providing me any benefit?

I doubt we will increase our electric usage much unless we start using some electric space heating during the winter (the back bathroom does get a little too cold at times for my wife), or we buy one of the new 200-mile range EVs next year and start driving it more than the Leaf. I test drove one of the Bolts at the auto show this year and it was pretty tempting, but I'm waiting to see what Nissan, Tesla, and VW do in the next year or two.

Thx,
TT
 
ttweed said:
At any rate, it looks like I can maybe be less concerned about charging the Leaf only at Super Off-peak times, a practice which I have always been very diligent in maintaining? I guess I can feel free to charge it in the middle of the day if need be from now on, if I am ending up with a total cumulative credit which I didn't use and isn't providing me any benefit?

Yeah in your case, if your LEAF needs a charge, charge it. You have plenty of excess production for it. As you probably know, there is little difference from super off peak and off peak anyways. - If I need a charge during off-peak, then I do it. For you, you could even charge during peak during the summer - probably 100 times and not change your bill.

In my case, I never charge on-peak in summer, since it is cheaper to drive on fossil fuels with the ridiculously high peak rate. When I leased my first LEAF I did not have solar as I didn't consider it cost effective - the summer on-peak back then was .27/kWh. When SDG&E raised the peak to .49/kWh - that changed the economics. I think I could run a diesel gen-set for less than that. :roll:
 
philip said:
sub3marathonman said:
OK, once again, I'm not from California, but I'd appreciate a bit further explanation about this.

In California, we have the choice of time of use or tiered billing (for the Investor owned utilities anyways). If you are on TOU, then the utility tracks both the retail dollar amount of NET generation plus the energy usage amount. The only time you will receive the ~.04/kWh generation credit is if you are a NET producer over the true up period. The retail amount that is tracked can only be used against energy purchases in the same true up period - if you have a credit at true up, you lose it.
...
When SDG&E raised the peak to .49/kWh - that changed the economics. I think I could run a diesel gen-set for less than that. :roll:

Thank you phillip, your entire explanation, as well as your other statements here, were a huge help in understanding it! It is not broken down by peak, off-peak, and super-off-peak.

Do all PV installations have to be on a certain rate (TOU2)? I wasn't sure if ttweed had a choice of the tiered billing, and if so I suppose it would have come out owing more money. Are there any residential demand rates? I didn't immediately see any when I looked.

I'm now wondering if you (phillip) have installed PV at your location, since the economics have shifted so.
 
Phillip is right -- ttweed was a net consumer of electricity so there were no kWh credited at 4 cents per.
The credit accrued from kWh's sent back to the utility during peak and shoulder being worth more than a kWh consumed at night.

Look at this example (not the actual rates of ttweed):
peak: 20 cents per kWh
shoulder: 15 cents per kWh
night: 10 cents per kWh

Say
3 peak kWh generated, one used
1 shoulder kWh generated, 2 used
1 night used

Net zero use,
but generation worth 3*20 + 1*15 = 75 cents
Consumption cost 1*20 + 2*15 + 1*10 = 60 cents

That 15 cent credit could be used for
0.75 kWh extra peak consumption; or
1.0 kWh extra shoulder consumption; or
1.5 kWh extra night consumption

Addendum: Phillips says that the credits car only be used in the same peak/shoulder/night periods they accrued in.
 
philip said:
It is more complicated than that and depends on the time of the year.

In California, PV has pushed the peak into the afternoon/evenings. A lot of this has to do with utility-scale solar farms and lesser to residential rooftop PV. In fact, the grid-scale farms have to curtail production during the middle of the day at this time of the year due to over-production/low demand - yet at the same time residential NET metering customers are "selling" this power to the grid at peak rates. Residential installs do not have the capability to curtail production, so the utility "must take" the power generated from NET metering customers.

FWIW, the California IOUs have or are in the process of changing the peak times to the afternoon/evenings.

You can look at the current demand on the CA ISO page. If you scroll down to the NET demand chart, the green line shows what the traditional power plants are providing - look at the big dip in the chart in the middle of the day (for this time of year) - a lot of traditional plants have to go idle, which raises their net operating cost. Residential PV is "behind the meter" so it shows up as reduced demand on these charts. The solar shown is the utility scale plants.

http://www.caiso.com/Pages/TodaysOutlook.aspx
These utility scenarios of energy sources are in flux, and not just from renewables coming online. Currently hydro is running at about the same load throughout the day, and some 20% of CA energy is a mixture of nuclear and coal imports. My guess is that CA will not renew their contracts with the exporters as they expire, and in the near future hydro will be used for the early evening load not covered by PV.

I know that plans in my area of the SW United States are to close some coal plants in the next ~ 5 years and I'm reasonably sure the driver is anticipated drop in exports.
 
sub3marathonman said:
Do all PV installations have to be on a certain rate (TOU2)? I wasn't sure if ttweed had a choice of the tiered billing, and if so I suppose it would have come out owing more money. Are there any residential demand rates? I didn't immediately see any when I looked.

I'm now wondering if you (phillip) have installed PV at your location, since the economics have shifted so.

No they do not have to be time of use. We have a choice of tiered, solar TOU and EV TOU. ttweed and I are both on EV-TOU2, which basically means that we have one meter for both our homes and EV charging and we get a "super" off-peak rate that is for EV charging between 12am and 5am.

I have a 5.7KW PV system - been running for almost two years. It generates about 70% of our energy use over the year, but our bill is near zero due to time of use.
 
SageBrush said:
Addendum: Phillips says that the credits car only be used in the same peak/shoulder/night periods they accrued in.

Not sure where I said that - maybe I was unclear somewhere, but, in California, credits generated in one period can be used in another through-out the 1 year true up period.
 
SageBrush said:
These utility scenarios of energy sources are in flux, and not just from renewables coming online. Currently hydro is running at about the same load throughout the day, and some 20% of CA energy is a mixture of nuclear and coal imports. My guess is that CA will not renew their contracts with the exporters as they expire, and in the near future hydro will be used for the early evening load not covered by PV.

I know that plans in my area of the SW United States are to close some coal plants in the next ~ 5 years and I'm reasonably sure the driver is anticipated drop in exports.

I don't think we import coal power anymore, we do import quite a bit of hydro from the PNW - in fact there is a HVDC line that runs from Washington all the way to LA for this. Pretty interesting circuit if you have time to read up on it- it has the ability to use ocean/ground as a return path. Our in-state nuclear is down to about 2 GWs now, for better or worse...
 
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