Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

I've had my solar PV (Grid Tie) system running in SDGE territory since January. I now feel like I have enough data (6+ months worth) to think about which billing system is the best one for me. I'm a little confused about the options and how they all work. I also have an EV, so I could get an EV TOU rate as another option.

DR: I'm sure that the system is sized so that it will either cover 100% of my use (averaged year-round) or to the extent it doesn't, all my use will stay in the Baseline Tier 1, which currently is about $0.14/kwh. This is what I'm currently on, and is my default choice.

EV-TOU 2 : the lowest rate on this plan is the super off peak rate from 12a to 5pm which is about $0.13. All the other rates are higher. I'm pretty sure there's no way this could be a better deal than the DR rate.

DR-SES : This is actually a TOU plan, with the highest rate (Summer Peak, 11a-6pm M-F from May thru October) of $0.27/kwh. The lowest rate is $0.176. At first glance, this also doesn't seem to be able to beat my current DR plan.

However, my understanding (which may be wrong) is that under DR-SES, the net metering is not done on the # of KWH you use/generate, but rather on the $ you use/generate. If true, then it may be better for me to get credited during 11a-6pm for $0.27/kwh, which is when 99% of my sso I can use this credit to offset my power draw during other times when the rate is lower (ranging from $0.191 to $0.176). In essence, power generated during the daylight hours would be getting me a roughly 50% bonus.

Am I correct about these assumptions? Anyone on DR-SES and been through a full year's cycle and can verify how the accounting works?

(*Note: all these rates are from last year's tables, I know rates increased a bit September 1st)

Comments

  • BB.BB. Super Moderators Posts: 26,758 admin
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    Do you have tiered rates too (the more kWH you use, the higher rates you pay)?

    This was a big mess in Northern California about 10+ years ago... For awhile, they did not let excess kWH generated in one time period (say summer afternoons) to be credited in during off peak times (at night). It was so bad, that the extra meter dedicated for EV charging was driving up the overall power bill and people were disconnecting from the whole EV rate plan. It was a real mess and the changes made were (apparently) in agreement with the filed rate plan (i.e., it was ambiguous).

    I would talk directly with the utility and some sample power usage (like generating 10kW per afternoon peak power rates and using 10-20 kWH during off peak--Or whatever works for your home) and see what they calculate.

    There was enough room in the PG&E rates to drive an armored car full of money through.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • soylentgreensoylentgreen Solar Expert Posts: 104 ✭✭
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    Yes, the DR rate schedule (that I'm on) has 4 tiers:
    $0.138/kwh first 0-303KWH
    $0.159 303-394
    $0.289 394-606
    $0.309 above 606

    With the PV system in place, my overall use is either going to stay below zero, or perhaps go a tiny bit into Tier 1. It should never get into tier 2, even in the winter.
  • chris17660chris17660 Registered Users Posts: 2
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?
    Yes, the DR rate schedule (that I'm on) has 4 tiers:
    $0.138/kwh first 0-303KWH
    $0.159 303-394
    $0.289 394-606
    $0.309 above 606

    With the PV system in place, my overall use is either going to stay below zero, or perhaps go a tiny bit into Tier 1. It should never get into tier 2, even in the winter.

    I just switched from TOU-2 back to DR rates. I'm in the North County area. I hope this was not a mistake. My house powered 100% by electricity including heating. For most months, I'm a net producer. In the winter I will hit tier 2 rates in January and Feburary.

    My original thought was that I could sell back to the utility at higher rates in the summer and buy it back at the lowest rate overnight when I'm charging my EV. In the end, I decided it was worth it to have the convenience of using the electricity whenever we wanted. My wife was annoyed about having to use the oven or dryer at off peak hours. My total bill at trueup last year was less than $100.

    I talked with SDG&E and they believe that unless you consistently hit tier 3 or 4, it isn't really worth going to a TOU rate plan.
  • soylentgreensoylentgreen Solar Expert Posts: 104 ✭✭
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    Thanks, Chris, that's interesting.

    I found another SDGE recommendation which suggested that if you generate more power between 11a and 6p, then the TOU rate may be better for you. May panels are all West/SouthWest facing, which means pretty much *all* of my power generation is during those hours.

    Current plan is to look at the data when I hit my one-year anniversary and see how the #s look.
  • bill von novakbill von novak Solar Expert Posts: 694 ✭✭✭✭
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    Here at Qualcomm we have an active EV group, and a lot of them have solar PV. The consensus has been that people see no benefit in moving away from the DR plan.
  • chris17660chris17660 Registered Users Posts: 2
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?
    Thanks, Chris, that's interesting.

    I found another SDGE recommendation which suggested that if you generate more power between 11a and 6p, then the TOU rate may be better for you. May panels are all West/SouthWest facing, which means pretty much *all* of my power generation is during those hours.

    Current plan is to look at the data when I hit my one-year anniversary and see how the #s look.


    Yes, I would love to hear more about your observations. My panels are all face south so I also generate the bulk of the power during peak hours. The delta between peak and off-peak rates are meaningful in the summer months but unfortunately SDGE does not offer a very good spread in the winter months. So I think for the TOU plan to be attractive you have to 1. use enough energy AND 2. be able to control the time in which you use that energy. In theory I should be exactly that type of customer. I have a EV that requires significant energy and I can charge it overnight and I have an ALL electric home. I even considered putting my hybrid heat pump water heater on a timer. In the end, I don't think the math works out. I guess I'll know for sure upon my trueup next year.
  • bstrbstr Registered Users Posts: 2
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    I've been closely tracking my daily production since my PV system was installed 5 months ago and usage since getting an EV 10 months ago. I chose to stay on SDG&E's EV-TOU2 rate and compare to DR-SES. Based on my usage and production profiles* (% used/produced in each time period) and with confidence in what I will produce and consume in a calendar year, the tipping point occurs when usage is 60% greater than production. For users with relatively small systems used to avoid upper tier pricing, EV-TOU2 is better. For those using less owning larger systems closer to 100% offset, DR-SES is better. In the end, the difference is never very great, ~$50-100/yr either way.

    *Profiles

    Production
    Peak % 65.17%
    Off Peak % 34.83%

    Usage
    Peak % 18.36%
    Off Peak % 33.38%
    Super Off Peak % 48.26%



    chris17660 wrote: »
    Yes, I would love to hear more about your observations. My panels are all face south so I also generate the bulk of the power during peak hours. The delta between peak and off-peak rates are meaningful in the summer months but unfortunately SDGE does not offer a very good spread in the winter months. So I think for the TOU plan to be attractive you have to 1. use enough energy AND 2. be able to control the time in which you use that energy. In theory I should be exactly that type of customer. I have a EV that requires significant energy and I can charge it overnight and I have an ALL electric home. I even considered putting my hybrid heat pump water heater on a timer. In the end, I don't think the math works out. I guess I'll know for sure upon my trueup next year.
  • BB.BB. Super Moderators Posts: 26,758 admin
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    Welcome to the forum Bstr.

    Thank you for the information--I agree that, usually, the differences in plans are designed to be near a net zero in cost differences for the "average customer"...

    However, if you have specific power needs (such as summer time A/C, water pumping, or other peak power usage)--A customer has to pay very close attention to billing/rate plans.

    On our rate plans (northern California PG&E), residential summer afternoon Time of Use power costs can be scary expensive at $0.55 per kWH (for heavy power users) vs $0.36 per kHW peak tier for flat rate residential rates.

    A decade ago, this caused grief for new solar GT customers that wanted to install a "small" system to see how will it worked. The state PUC forces solar GT customers onto TOU plans and those small gt customers actually saw their summer power cost increase, rather than decrease.

    Similarly, schools and other commercial customers saw their power bills increase after installing solar GT power systems due to how commercial power rates are calculated [from 2008].

    A couple of News Articles...


    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bstrbstr Registered Users Posts: 2
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    Thanks Bill. I guess I lost track of this thread and never got any notifications. Coincidentally, I stumbled onto the page again while doing the same SDGE research as before. I'm coming up on one year of solar PV production and will be considerably ahead, but looking to add a second EV. Trying to figure out the best rate plan is pretty difficult. Looks like I have to continue with manual comparisons.

    BB. wrote: »
    Welcome to the forum Bstr.

    Thank you for the information--I agree that, usually, the differences in plans are designed to be near a net zero in cost differences for the "average customer"...

    However, if you have specific power needs (such as summer time A/C, water pumping, or other peak power usage)--A customer has to pay very close attention to billing/rate plans.

    On our rate plans (northern California PG&E), residential summer afternoon Time of Use power costs can be scary expensive at $0.55 per kWH (for heavy power users) vs $0.36 per kHW peak tier for flat rate residential rates.

    A decade ago, this caused grief for new solar GT customers that wanted to install a "small" system to see how will it worked. The state PUC forces solar GT customers onto TOU plans and those small gt customers actually saw their summer power cost increase, rather than decrease.

    Similarly, schools and other commercial customers saw their power bills increase after installing solar GT power systems due to how commercial power rates are calculated [from 2008].

    A couple of News Articles...


    -Bill
  • SkiDoo55SkiDoo55 Solar Expert Posts: 414 ✭✭✭
    Re: Solar PV with SDGE Net Metering DR vs. DR-SES vs. TOU-2?

    Did my system in 2010 and wasn't forced to change from tiered flat rate. In Northern CA on PG&E. Added another 5 KW of panels last year, just selected same biling on PG&E paperwork on system upgrade. Might have depended on what rate schedule you had before?
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
  • soylentgreensoylentgreen Solar Expert Posts: 104 ✭✭
    I see SDGE has rolled out some new "Whenergy" plans:

    TOU-DR-P (Time of use Plus) - on a  'reduce your use' day it looks like they average your peak usage for the past 5 days (during 11am-6pm) and if you can go below it, you get a credit.   I'm not sure how the credit is calculated, but it looks like there is a $1.16/kWh bonus of some sort.

    SDGE also has a new plan comparison calculator which estimates which plan is best for you (though it doesn't include EV-TOU2 plans in the comparison).  
  • tigerdogtigerdog Registered Users Posts: 1
    I hope it's OK to reactivate an old thread. 

    We received a letter on 30 June 2017, notifying us of new plan options.  Since August, 2015, we've been running a DR plan with NEM.  Annualized, we are a net over-generator, only pulling from the grid between November and February.  We only pull from the grid between 5PM and 8AM, even in the winter months.   It seems like this is a classic case for ToU billing, but it is not at all clear from SDG&E's web site how ToU and NEM are related.  Does anyone have up-to-date information?  If there's a current thread, please point me in that direction.
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