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SDGE - Time Of Use (TOU) Rates. Good or bad for Net Metering?

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  • J.P.M.
    replied
    Originally posted by cebury View Post
    I should run this, too for ST folks as I still get family and friends asking if solar is still worth it in our area.

    Even for NEM1, unless it changes, in PGE territory the wall hits in 3.5 years on Dec 31, 2020 for folks on the "generally most PV favorable" TOU rate E6. The combo pain of peak window shift to outside solar production, shrinking Summer to 4 months and flattening the top peak rate all to minimize peak "banking" was an effective way to slow the death spiral of retail feedin net metering. PV cost/watt will have to drop a lot to match current payback. But who knows, CA could shoot for 100% renewable energy ? and raise base rates so much retail net merering wont be needed for a 5 year simple payback.
    If the effective death of net metering advantages under evolving T.O.U. doesn't kill residential PV, I bet it'll sure make residential PV a lot cheaper as the principle of selling to the market takes hold once the floor of net metering cost advantages drop out from under the CA PV industry. Might even hasten or aid battery development as well.

    (Side note to POCOs: Think about getting out in front of battery tech. Own, embrace and facilitate the tech instead of making it your competition. If you'd have done that w/ PV, things would be a lot different today.)

    I suspect the goal of the POCO's is to use solar and any other technologies to the extent they are viable and most cost effective. If that means 100% from renewables, so be it. But, NEM is not in the POCO's best interests. So, I'd expect them to do all they can to minimize it's impact on their operation and bottom line, as they are doing, but not with some vindictive goal of getting even or screwing their customers - that would be a childish and counterproductive way for them to look at it. And they don't. It's all about business and the bottom line for them, as it should be.

    As for PV being worth it, you simply gotta' run the numbers, and that takes understanding how the tariffs work as well as how much and in what ways electricity is used on an individual basis. Like I wrote, not rocket science, just involved. Every situation is different. At this time, thinking it can be made a one liner will lead to a classic case of GIGO. Unfortunately, running the numbers under T.O.U. is just not as simple as on a tiered tariff, and with multiple tariff plans to compare. it's more involved still.

    Shameless plug: Still the bottom line easiest path to the real goal of a lower electric bill (and not solar for its own sake it might be good to remember) is to simply use less electricity, first by turning stuff off and then time shift loads and so game the tariff, and then taking conservation measures to use less of that lowered and time shifted usage. Do all that, then see if some PV can be made cost effective for the remainder of the load.

    Along the way, folks will have the opportunity (or need, as may become apparent) to make choices between money and comfort or other priorities.

    Not as a value judgment, but as examples only: How much more $$ in electric bills is my comfort worth if I keep the house cooler ? Or, I've got a limited budget, so, do I want a bigger car payment or a cooler house ?

    Leave a comment:


  • cebury
    replied
    Originally posted by sensij View Post

    Anyway, if DR-SES kept the same rates but just adopted the new periods in summer, the results are dire. The -62 annual NEM charge I posted above becomes a +238 bill. Ignoring July, the bill jumps $250, from 63 to 318. New NEM-ST customers are about to get screwed.
    I should run this, too for ST folks as I still get family and friends asking if solar is still worth it in our area.

    Even for NEM1, unless it changes, in PGE territory the wall hits in 3.5 years on Dec 31, 2020 for folks on the "generally most PV favorable" TOU rate E6. The combo pain of peak window shift to outside solar production, shrinking Summer to 4 months and flattening the top peak rate all to minimize peak "banking" was an effective way to slow the death spiral of retail feedin net metering. PV cost/watt will have to drop a lot to match current payback. But who knows, CA could shoot for 100% renewable energy ? and raise base rates so much retail net merering wont be needed for a 5 year simple payback.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by sensij View Post

    Yeah, the 117 it shows is because of the minimum bill... the -62 is what it would be without that. As far as I can tell, their estimating tool is accurate, for rates as they exist today. They do a lousy job of explaining *why* one plan differs from another, and for anyone missing the July 28th deadline for TOU grandfathering, getting on DR-SES could be a disaster.
    If things with T.O.U. timing go as they seem to be, it'll kill residential solar development in San Diego and reverse my negative feelings about what an existing (particularly an NEM 1.0) PV system will do to the price of a house around here. Maybe the pricing will flatten out a bit and remove some of the difference.

    Leave a comment:


  • sensij
    replied
    Originally posted by cebury View Post

    So it looks like the DR numbers matched, but the DRSES differed between -62 and 117 because of the tariff differences it was run under, is that right? Did you find any discrepencies yet that would cause you to question the estimated annual costs for the My Pricing Plan (rate comparison) report?
    EDIT: i see you answered my question while i posted. Thanks.

    I believe SDGE can be misleading in their descriptors but if you cant trust their bill estimating tools, IMHO thats indefensible because that system should be fairly accurate programmatically.
    Yeah, the 117 it shows is because of the minimum bill... the -62 is what it would be without that. As far as I can tell, their estimating tool is accurate, for rates as they exist today. They do a lousy job of explaining *why* one plan differs from another, and for anyone missing the July 28th deadline for TOU grandfathering, getting on DR-SES could be a disaster.

    Leave a comment:


  • cebury
    replied
    Originally posted by sensij View Post
    Ok, I updated the table above with the DR-SES calculations, providing the breakdown in billed usage between the TOU periods. I just used the current tariff (3/1/17) for all months. This has not been verified against an actual DR-SES bill, but I used the same spreadsheet template that I had used for EV-TOU-2, which I did validate, and just redefined the TOU periods per the DR-SES definition.

    Even setting aside the unusual July, the DR-SES bill would come out well under the minimum bill of ~$120, in agreement with what SDG&E's rate comparison tool shows. I really didn't expect that.... in fact, I had moved them to the DR tariff when we moved out, because with what I guessed their consumption pattern would be with the home daycare, I didn't think the TOU tariff would be good.

    Next update I'll take another look at this, except with the new DR-SES hours, with the peak shifted later.
    So it looks like the DR numbers matched, but the DRSES differed between -62 and 117 because of the tariff differences it was run under, is that right? Did you find any discrepencies yet that would cause you to question the estimated annual costs for the My Pricing Plan (rate comparison) report?
    EDIT: i see you answered my question while i posted. Thanks.

    I believe SDGE can be misleading in their descriptors but if you cant trust their bill estimating tools, IMHO thats indefensible because that system should be fairly accurate programmatically.

    Leave a comment:


  • sensij
    replied
    Originally posted by J.P.M. View Post

    Understood. Thank you. Not a big rush. Back burner stuff for me too. Sometimes I wish I was less of a Luddite. Not a beef and my shortcoming, but it'd be easier to post a picture of the summary portion of my DR- tiered spreadsheet than verbal explanations. Still working (figuring out best way) on DR-SES sheet.

    Other current project: Trying to figure out efficacy of various ways to estimate and account for Davis solar sensor deterioration w/respect to panel deterioration estimates over the last 3+ years. Got my hands sort of full just now.
    I've found that to get the best agreement with the actual bill, the EV-TOU-2 plan needs to be calculated in two columns for each component of the bill. The components I calculate are:

    Delivery
    Generation
    DWR-BC
    City Franchise Fee
    Franchise fee on others
    State surcharge tax
    State regulatory fee

    For each TOU period in each bill, each of those components is calculated as a "NEM charge" if the usage in that period is positive, or a "NEM credit" if the usage is negative. That allows the NEM charges and NEM credits on the final page of the bill to make sense. (Separating out NBC's for NEM-ST is a separate project, and I'll need another bill or two to feel confident in my approach there).

    I took a stab at applying the new rates. For anyone who missed it, the final GRC Phase 2 decision is here:

    http://docs.cpuc.ca.gov/PublishedDoc.../191913288.PDF

    The new TOU periods across all plans will be: new tou.JPG





    I can't directly apply this to the existing DR-SES since winter only has two TOU periods right now, and the new version will have three. The extra special condition for March and April is probably there just to make the spreadsheets even more complicated.

    Anyway, if DR-SES kept the same rates but just adopted the new periods in summer, the results are dire. The -62 annual NEM charge I posted above becomes a +238 bill. Ignoring July, the bill jumps $250, from 63 to 318. New NEM-ST customers are about to get screwed.

    Here is a link to the spreadsheet, for anyone who wants to take a look:

    https://www.dropbox.com/s/kr963t35z8...king.xlsx?dl=0

    Last edited by sensij; 07-16-2017, 11:10 PM.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by sensij View Post

    Actual DR bill is the amount I calculated from the tariff that was in effect at the time, verified to within 0.02 of the actual bill. (i'm more like 0.15 off in the july 2016 bill, not sure why but the bill was corrected a couple months later and not worth figuring out. Also, April 2017 bill might get corrected, downloaded usage shows 8 kWh more consumed than what the bill that month showed)

    DR bill under current tariff is what that usage would have been if the 3/1/17 tariff had been in effect for the entire period.



    Actual billing days, cycle 18.



    See above. The "actual" column is the tariff in effect at that time, the "current tariff" column uses 3/1/17 tariff for all 12 bills.



    Coastal



    Gas+Electric



    I'll share the spreadsheet when I get done cleaning it up, lots of other side projects going on in it at the moment.
    Understood. Thank you. Not a big rush. Back burner stuff for me too. Sometimes I wish I was less of a Luddite. Not a beef and my shortcoming, but it'd be easier to post a picture of the summary portion of my DR- tiered spreadsheet than verbal explanations. Still working (figuring out best way) on DR-SES sheet.

    Other current project: Trying to figure out efficacy of various ways to estimate and account for Davis solar sensor deterioration w/respect to panel deterioration estimates over the last 3+ years. Got my hands sort of full just now.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by sensij View Post
    Ok, I updated the table above with the DR-SES calculations, providing the breakdown in billed usage between the TOU periods. I just used the current tariff (3/1/17) for all months. This has not been verified against an actual DR-SES bill, but I used the same spreadsheet template that I had used for EV-TOU-2, which I did validate, and just redefined the TOU periods per the DR-SES definition.

    Even setting aside the unusual July, the DR-SES bill would come out well under the minimum bill of ~$120, in agreement with what SDG&E's rate comparison tool shows. I really didn't expect that.... in fact, I had moved them to the DR tariff when we moved out, because with what I guessed their consumption pattern would be with the home daycare, I didn't think the TOU tariff would be good.

    Next update I'll take another look at this, except with the new DR-SES hours, with the peak shifted later.
    Understood.

    Leave a comment:


  • sensij
    replied
    Ok, I updated the table above with the DR-SES calculations, providing the breakdown in billed usage between the TOU periods. I just used the current tariff (3/1/17) for all months. This has not been verified against an actual DR-SES bill, but I used the same spreadsheet template that I had used for EV-TOU-2, which I did validate, and just redefined the TOU periods per the DR-SES definition.

    Even setting aside the unusual July, the DR-SES bill would come out well under the minimum bill of ~$120, in agreement with what SDG&E's rate comparison tool shows. I really didn't expect that.... in fact, I had moved them to the DR tariff when we moved out, because with what I guessed their consumption pattern would be with the home daycare, I didn't think the TOU tariff would be good.

    Next update I'll take another look at this, except with the new DR-SES hours, with the peak shifted later.
    Last edited by sensij; 07-16-2017, 06:26 PM.

    Leave a comment:


  • sensij
    replied
    Originally posted by J.P.M. View Post
    Questions:
    1.) Just confirming: "Actual DR Bill" column is data from the bill ?, with "DR Bill under current tariff" column containing data calculated from your spreadsheet ?
    Actual DR bill is the amount I calculated from the tariff that was in effect at the time, verified to within 0.02 of the actual bill. (i'm more like 0.15 off in the july 2016 bill, not sure why but the bill was corrected a couple months later and not worth figuring out. Also, April 2017 bill might get corrected, downloaded usage shows 8 kWh more consumed than what the bill that month showed)

    DR bill under current tariff is what that usage would have been if the 3/1/17 tariff had been in effect for the entire period.

    Originally posted by J.P.M. View Post
    2.) Do you use actual # of billing days or a calendar month ? from looking at the adjacent months direction of variation, my guess is calendar month, but stress that's a guess and not a knock. What billing cycle does the data work to ?
    Actual billing days, cycle 18.

    Originally posted by J.P.M. View Post
    3.) Do data shown use the tariff currently in effect (as of 03/01/2017) or the tariff that was in effect at the time of use ? I suppose I could back calc the answer to that , same as the ans. to 2 above, but it's easier to ask.
    See above. The "actual" column is the tariff in effect at that time, the "current tariff" column uses 3/1/17 tariff for all 12 bills.

    Originally posted by J.P.M. View Post
    4.) Coastal or inland territory ?
    Coastal

    Originally posted by J.P.M. View Post
    5.) Gas + electric service to the property or all electric and no gas service ?
    Gas+Electric



    I'll share the spreadsheet when I get done cleaning it up, lots of other side projects going on in it at the moment.
    Last edited by sensij; 07-16-2017, 05:46 PM.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by sensij View Post

    Ok, here is the first half of the analysis. This is for a 1288 sq ft home in the Clairemont neighborhood of San Diego, 3 person family, no central A/C but a window unit installed in the main room, home daycare business run out of the house during the day. The PV system is 3.1 kW, south facing (176 deg azimuth) at 18.5 deg tilt, installed in april 2015.

    Here is what the rate comparison tool from SDG&E shows: plan comparison.JPG









    The estimated cost per year is based on the prior 12 months usage. Here is the DR tariff results, from running actual usage through the spreadsheet (and using the bills actually received):
    Bill ending Usage Actual DR Bill DR Bill under current tariff
    7/26/2016 -244 -49 -54
    8/24/16 4 1 1
    9/25/16 -20 -4 -4
    10/25/16 58 10 11
    11/24/16 246 47 51
    12/26/16 282 53 58
    1/25/17 328 65 67
    2/26/17 264 53 54
    3/27/17 20 5 4
    4/26/17 15 1 1
    5/25/17 -35 -8 -8
    6/26/17 -49 -11 -11
    Total 868 163 170
    The monthly bill amounts exclude the CA Climate credit (except to the extent they affect taxes), and exclude Reduce Your Use awards. The minimum bill is not a factor for this usage because the actual owed amounts over the course of the year exceed the minimum bill amount.

    July is something of an outlier because that is the month we moved out of the house, and the new family did not move in until later in the month, so usage was extremely low the first 2-3 weeks.

    As you can see, the agreement between what SDG&E says the bill would be, and what I'm calculating, is very good, just $1 different.

    I'll post the DR-SES analysis for this usage soon.
    Thank you.

    Questions:
    1.) Just confirming: "Actual DR Bill" column is data from the bill ?, with "DR Bill under current tariff" column containing data calculated from your spreadsheet ?
    2.) Do you use actual # of billing days or a calendar month ? from looking at the adjacent months direction of variation, my guess is calendar month, but stress that's a guess and not a knock. What billing cycle does the data work to ?
    3.) Do data shown use the tariff currently in effect (as of 03/01/2017) or the tariff that was in effect at the time of use ? I suppose I could back calc the answer to that , same as the ans. to 2 above, but it's easier to ask.
    4.) Coastal or inland territory ?
    5.) Gas + electric service to the property or all electric and no gas service ?
    Thanx again. Look forward to how you do T.O.U.
    Last edited by J.P.M.; 07-16-2017, 05:14 PM.

    Leave a comment:


  • sensij
    replied
    Originally posted by sensij View Post

    When I get some time this weekend I'll​​​ post a real life example for a typical light A/C, non-EV, PV sized less than 100% scenario. It appeared DR-SES was better for that person, even though the billed usage was closer to example 1 above than example 2. Definitely wouldn't mind peer review of the results, though.
    Ok, here is the analysis. This is for a 1288 sq ft home in the Clairemont neighborhood of San Diego, 3 person family, no central A/C but a window unit installed in the main room, home daycare business run out of the house during the day. The PV system is 3.1 kW, south facing (176 deg azimuth) at 18.5 deg tilt, installed in april 2015.

    Here is what the rate comparison tool from SDG&E shows: plan comparison.JPG




    The estimated cost per year is based on the prior 12 months usage. Here is the DR tariff results, from running actual usage through the spreadsheet (and using the bills actually received):
    Bill ending Usage on-peak semi-peak off-peak Actual DR Bill DR Bill under current tariff DR-SES Bill under current tariff
    7/26/2016 -244 -222 -26 4 -49 -54 -125
    8/24/16 4 -146 59 93 1 1 -41
    9/25/16 -20 -139 65 54 -4 -4 -44
    10/25/16 58 -117 74 101 10 11 -20
    11/24/16 246 -2 -10 258 47 51 58
    12/26/16 282 0 1 281 53 58 66
    1/25/17 328 0 6 322 65 67 77
    2/26/17 264 0 -70 334 53 54 61
    3/27/17 20 0 -140 160 5 4 3
    4/26/17 15 0 -160 182 1 1 1
    5/25/17 -35 -130 36 58 -8 -8 -46
    6/26/17 -49 -143 63 32 -11 -11 -52
    Total 868 -900 -102 1879 163 170 -62
    The monthly bill amounts exclude the CA Climate credit (except to the extent they affect taxes), and exclude Reduce Your Use awards. The minimum bill is not a factor for this usage because the actual owed amounts over the course of the year exceed the minimum bill amount.

    July is something of an outlier because that is the month we moved out of the house, and the new family did not move in until later in the month, so usage was extremely low the first 2-3 weeks.

    As you can see, the agreement between what SDG&E says the bill would be, and what I'm calculating, is very good, just $1 different.

    I'll post the DR-SES analysis for this usage soon.
    Last edited by sensij; 07-16-2017, 06:24 PM.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by cebury View Post

    Was the cause of the problem on your account due to overproduction (so therefore showing the same amount on all the rate plans)? Of the various points you made, my primary concern was if those numbers shown for alternative billing plans were incorrect.

    Prior to solar, i had tested PGEs numbers for alternative plans and they were all within a couple percent for my profile. I have yet to run the latest plans against it.
    The beefs I have are with the simplistic way SDG & E throws out information. This blub is an example of the basic uselessness resulting from the way they put stuff out. It's misleading by its simplicity and lack of accuracy. In my case whether the cause of the uselessness was overproduction or not, it's still wrong and I believe what the OP got, which is identical in format may lead the OP to think T.O.U. will save him some money - Well it may, or it may not be, but for one thing, there' no reasoning or numbers behind the reasoning to back it up. That blurb is an example of the uselessness and misinformation that SDG & E often puts out. BTW, to say that putting "more" information out htere would be useless because no one would bother is first of all, not true (some would) and second and more importantly, an insult. But I guess mu anachronistic sensibilities are showing on that one.

    Here's the deal: If I and others can come up with what are viable methods to compare billing schemes and rate plans to any desired degree of accuracy, and in so doing make more informed and perhaps more intelligent choices about rate plans, I'm quite sure SDG & E and the other POCOs could do the same. Basically, if I can do anyone can. That they don't, and putting myself in their shoes is certainly understandable from their perspective. Doing so will cause problems of lower revenue and pissed off customers who are too lazy and too ignorant to do anything but bitch about their self induced high electric bills. Giving them the tools to help themselves will not help the POCO.

    That they instead put out what is IMO, mostly useless and often misleading or easily misunderstood and incomplete information is what my beef is about.

    If they're going to put out information, get it right and get it complete, or at least make it reasonably possible to get more information, or don't bother with the cynical fluff at all. In its present format, its mostly, IMO, a counterproductive waste.

    I appreciate the CPUC is on the POCO's asses about public information. But crap like this isn't information as much as misinformation that can lead sheeple into less than optimum outcomes.

    Leave a comment:


  • cebury
    replied
    Originally posted by J.P.M. View Post

    But I've got some problems with the info SDG & E put out on that sheet. The one I got shows the current cost/yr. as equal to my billing year to date charge - for all plans. That's not cost /yr. and even if it was, that's useless for comparison purposes for me. I doubt it's accuracy and therefore its usefulness.
    Was the cause of the problem on your account due to overproduction (so therefore showing the same amount on all the rate plans)? Of the various points you made, my primary concern was if those numbers shown for alternative billing plans were incorrect.

    Prior to solar, i had tested PGEs numbers for alternative plans and they were all within a couple percent for my profile. I have yet to run the latest plans against it.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by sensij View Post
    If you overproduce your consumption, the charge for all plans will show as ~$120 dollars.

    When I get some time this weekend I'll​​​ post a real life example for a typical light A/C, non-EV, PV sized less than 100% scenario. It appeared DR-SES was better for that person, even though the billed usage was closer to example 1 above than example 2. Definitely wouldn't mind peer review of the results, though.

    At one point, I did in fact model *every* one of the tou plans offered by SDG&E (along with most from SCE and PG&E). I don't have actual bills to validate against for the less commonly discussed plans though, so ymmv.
    Mostly Agreed. Appreciate the comment/any input. Annual overproduction will indeed still result in a $120/year bill, less any CA climate credit. I was less than clear about that.

    My examples dealt with situations where the system offset was < 100%, and some examples of how summer billing may be look tiered vs. T.O.U. as f(amount of electricity billed) as a way of showing some of the ways that the SDG & E statement (that I consider self serving and disingenuous) about DR-SES being better for users may not always be true as they seem to want users to infer, or that oversizing and then getting on T.O.U. is the way to go. It ain't.

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