SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

TickTock
TickTock Registered Users Posts: 16 ✭
in Grid Tie and Grid Interactive Systems #1
After running my system Since September on the Time of Use program, I am fairly certain this is not the most cost-effective program for a solar array. Every bill I've gotten indcated my bill was $X.xx higher "thanks" to time of use. This is because most of my production throughout the winter was off-peak. The last three months I actually produced more kWh then I used overall but am still paying because I use more then I produced on-peak. Meanwhile, I've got over a MWh of off-peak credit accumulated.

So summer's coming around, I was wondering if anyone has experience with TOU in the summer. Can I expect the trend to continue. Should I switch to basic plan now or can I reasonably expect my on-peak production to increase in the summer?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,598 admin
    #2
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    You can use the PV Watts website. On the output page, there is a Output Hourly Data option that you can load into a spread sheet and see how your average power output falls against the TOU bins...

    Every utility seems to have its own spin on TOU--And those change over time.

    In Northern California, my TOU was pretty straight forward--Noon-6pm was peak power, all else was off-peak. And Peak was only >> flat rate power during the "6 months of summer".

    Since my plan is between noon and 6pm--Almost 1/2 of my output falls in the noon-6pm (especially because we have daylight savings time--you don't have that in Arizona). And it is pretty easy for us to schedule around the weekday afternoons for power usage.

    However this E-7 TOU plan was too good for consumers... There is a new plan that new GT solar installs must use that has peak, partial peak, and off-peak that can range from 10am to 9pm or so (plus partial peak on weekends)... With such a wide power usage time window--it would have been much more difficult for me to schedule my optional loads outside the TOU penalty... And we don't generate much power past 4pm anyway--so I have to use the higher priced power into the evening/night.

    While I may still come ahead for the new E-6 TOU plan--I would probably go with flat rate (E-1) and just avoid the whole TOU nightmare (using power at the wrong time can result in 3-6x pricing penalties).

    The other thing that sounds different regarding your plan--Our plan simply takes all of the power credits and turns them into dollars ("bank account") that can be applied to the next bill--regardless of peak/off peak distribution of charges.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #3
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    I am on the APS 9AM to 9PM TOU Mon - Fri , looks good to me I had to buy $4.47 of off peak last month and now have 2500+ kWh of credit on my on peak. Started using AC but my daily is still in the positive. We shall see if the summer peaks AC usage will be completely offset.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    solar_dave wrote: »
    I am on the APS 9AM to 9PM TOU Mon - Fri , looks good to me I had to buy $4.47 of off peak last month and now have 2500+ kWh of credit on my on peak. Started using AC but my daily is still in the positive. We shall see if the summer peaks AC usage will be completely offset.

    Those 4 hours between 5pm and 9pm will kill you. Generation = low, usage = high.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • Jburgess
    Jburgess Solar Expert Posts: 130 ✭✭✭
    #5
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    Here’s my experience with SRP’s TOU plan (1-8pm peak)
    6.3 KW DC system near you.

    My month ends on the 15th, so May is Apr.16 though May 15.

    Month peak/off peak KWH production.
    May 228/899
    June ?
    July?
    Aug. 327/696
    Sept. 329/712
    Oct. 289/748
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #6
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    mike90045 wrote: »
    Those 4 hours between 5pm and 9pm will kill you. Generation = low, usage = high.

    That is true, but the 73kWh I generate a day is more than enough to carry me on those 5 hours. Still Yesterday which was a pretty big usage day and I netted a +21kWh back to the grid.
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  • cjmdwyer
    cjmdwyer Registered Users Posts: 10 ✭
    #7
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    I was kind of shocked when the May 1st SRP peak hour change rolled around and our on peak useage really went down. I kind of figured it was because a good portion of on-peak is during peak p/v production time. One day my peak time useage was actually negative 1 kwh. We were using way more peak in april, when we first switched to time of use plan. Peak then is 5am to 9am and 5pm to 9pm. Not the best p/v production hours. But in the months from Novemeber through April, on-peak rates aren't too bad. It's the summer peak and "extra special bonus peak" hours that the rates are crazy high. We will see what happens when we have to run the a/c all day long.................
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  • TickTock
    TickTock Registered Users Posts: 16 ✭
    #8
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    Thanks all. Lots of intersting bits of information. Sounds like there is some hope for TOU this summer. I guess I'll stick it out for the summer before making any changes.
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #9
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    By the way, the APS 9am to 9pm plans are no longer available. You fortunately can stay on it however as in my experience is the best by far for a solar grid tied user.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #10
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    solarix wrote: »
    By the way, the APS 9am to 9pm plans are no longer available. You fortunately can stay on it however as in my experience is the best by far for a solar grid tied user.

    Well I find that interesting. I was starting to think that the shorter time frame noon to 7PM peak plan might be better during the summer months because of all the off peak AC usage, like overnight.

    I think when I get a few minutes I will set up some data storage and collect one minute usage/generation data and see how it plays out this month. Headed to 110F this weekend.
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  • TickTock
    TickTock Registered Users Posts: 16 ✭
    #11
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    So 12 months have gone by since installing the array. SRP is nice enough to show how much you would have paid on their other programs. It appears TOU is the *worse* plan if you have a large array (at least for me). Peak productions just doesn't line up with on-peak hours unfortunately (except for 2 months out of 12).

    We have at timer on the hot water heater and are concientious of use during peak but but unwilling to turn off AC in the late afternoon. My cost for the last 12 months was $950. Had I been on the basic plan it would have been $890 and, curiously, had I been on EZ-3 it would have been $870. Needless to say, I've switched over to EZ-3.

    To get the analysis, on SRPnet click "Choose the Righ Price Plan" and then click the "Compare" Tab. It is grey and that fooled me into thinking there was nothing there but click it and you should see a nice comparison of the three plans. Note that the costs include the taxes and connection fees (for example, I generated more than I used in May but still owed SRP).

    Here are the details for those data-junkies out there:
    picture.php?albumid=25&pictureid=166

    Also, here is a comparison of the 12 months before and 12 months after the array installation for anyone looking for hard data for ROI analysis:
    picture.php?albumid=25&pictureid=168
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,598 admin
    #12
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    I am impressed with your Utility!:D

    I wondered if any utility would use the smart meter data and review a customer's usage to compare rate plans.

    The E-6 TOU plan for our (PG&E) utility is so complex that nobody could guess how it stackups up against their power usage patterns.

    It takes around 4 typed pages just to discribe the rate plan and the charges (tiered, baseline amount, by season, days of week, holidays, using the "old" daylight savings times rules, meter charge, minimum charge, etc.).

    And none of that describes the 1 year Net Metering rules and regulations. :roll:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Jburgess
    Jburgess Solar Expert Posts: 130 ✭✭✭
    #13
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    Bill,

    That one confusing rate structure.

    SRP bases it’s estimate for TOU or EZ3 on 25% / 10% on peak respectively. The current plan and Basic are based on usage history.

    Hourly history is not available from their grid, Only daily usage. My meter is read once a day at 12:16 AM, Missed readings are retried at 4:16 AM.

    I wish they had hourly reading available, as well as readings for my solar meter, but they only make the daily revenue meter reading available.
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  • TickTock
    TickTock Registered Users Posts: 16 ✭
    #14
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    Interesting. So, since I was on the TOU plan, the EZ-3 data was only a best guess... Well, tune in next year and I'll have 12 mos. on EZ-3 for comparison. Should be able to normalize to each other based on the Basic plan computation to make a reasonable comparison.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #15
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    I think I found an interesting problem on the APS TOU plan, SO far I have an excess of on peak for the year so I moved my swimming pool loads to on peak to burn some of that excess. WTF my bill went up while the purchase amount from the utility remained about the same.

    July:
    Total electricity from APS, in kWh 1763
    On-peak electricity from APS, in kWh 590
    Off-peak electricity from APS, in kWh 1173

    August
    Total electricity from APS, in kWh 1649
    On-peak electricity from APS, in kWh 649
    Off-peak electricity from APS, in kWh 1000

    Where the big change happened is in the service delivery charge, which in July was 6.77 and Aug was 34.95. Shocking development they are charging to deliver my credited hours! My charges for Generation actually went down $3.

    Now I am starting to think that the noon to 7pm plan looks better, as I can get more off peak generation and control my loads to my AC only during those peak hours which my solar can cover pretty well with the credits. APS claims to be able to analyze your bill and tell you the best plan but I think they don't really do that. THey don't really know your load profile so how can they?
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  • TickTock
    TickTock Registered Users Posts: 16 ✭
    #16
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    That *is* strange - especially since we are both in the same Phoenix area. I think I would just switch to Basic and not have to worry about balancing my on and off peak generation and consumption. That was my plan until SRP indicated EZ-3 would be better.
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  • Jburgess
    Jburgess Solar Expert Posts: 130 ✭✭✭
    #17
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    For me the TOU is best (1-8pm summer

    plans.jpg

    My system is sized to try cover my summer peak hour ($0.21 to $0.23/ KWH with tax), so almost all my use in summer is off peak.

    daily_use.jpg

    The down side of TOU is winter peak is 5-9 AM and 5-9 PM so there is little winter peak production from my solar. But at least there is only a $0.04 difference in peak instead of the $0.15 difference in summer.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #18
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    TickTock wrote: »
    That *is* strange - especially since we are both in the same Phoenix area. I think I would just switch to Basic and not have to worry about balancing my on and off peak generation and consumption. That was my plan until SRP indicated EZ-3 would be better.

    well the rates on basic keep me off that direction, they are about double the off-peak. I am still waiting on a call from APS about how the "DELIVERY SERVICE CHARGE" is calculated.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #19
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    It's obvious that pretty soon the increasing complexity of utilities' rate plans will be the primary reason people go off-grid! :p
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #20
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    Cariboocoot wrote: »
    It's obvious that pretty soon the increasing complexity of utilities' rate plans will be the primary reason people go off-grid! :p

    But I like them as my battery! :p
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,020 ✭✭✭✭
    #21
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    They make a pretty handy multi-billion dollar generator for charging batteries too :D But I;'ll always have some kind of fossil fuel genset tucked away close by (Until I get my Mr Fusion unit)

    Ralph
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  • TickTock
    TickTock Registered Users Posts: 16 ✭
    #22
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    solar_dave wrote: »
    well the rates on basic keep me off that direction, they are about double the off-peak. I am still waiting on a call from APS about how the "DELIVERY SERVICE CHARGE" is calculated.

    Yeah, as long as you are able to avoid your provider paying you wholesale for unused power by balancing your demand. I ended up with over 1000 kWh excess off-peak in April and was paid half what I pay for the same electricity that time of year. Did you get a better price (~50% retail) for your on-peak excess? I sure would hope so!
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  • TickTock
    TickTock Registered Users Posts: 16 ✭
    #23
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    OK. So SRP and I may not know my hourly consumption, but I do know my hourly production. I have 12 months of data at 5 minutes intervals. SRP is very forthcoming with data (I really like SRP - very rare to see such a customer orientation in a company with essentially no competitors) so I was able to compute the value of the energy produced on each of the programs (taking into account time of production, day of the week, and seasonal rates). Assuming I consume all my production (don't actually end up selling any at wholesale), we end up with the following result:

    picture.php?albumid=25&pictureid=169

    This doesn't take into account consumption beyond production which can make a difference but it does suggest that TOU is not optimal for large arrays (providing most of a household consumption) and EZ-3 looks favorable. However, when my Nissan Leaf arrives in February suddenly my array will be undersized as I pick up a very large off-peak load. I suspect TOU may get the nod at that point.
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  • Jburgess
    Jburgess Solar Expert Posts: 130 ✭✭✭
    #24
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    TickTock wrote: »
    (I really like SRP - very rare to see such a customer orientation in a company with essentially no competitors)

    Rather than a company, SRP is a municipal corporation with no investors or stockholder to answer to.

    Removal of that profit motive makes for a friendlier company doesn't it.

    For me what is most important is what do I have to pay out of pocket for the power I don't produce.

    The value of the power produced is important in figuring out the return on your investment.
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  • sub3marathonman
    sub3marathonman Solar Expert Posts: 300 ✭✭✭
    #25
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    TickTock wrote: »
    picture.php?albumid=25&pictureid=169

    What I find interesting is that somebody there decided that for July and August the TOU off-peak price for electricity should be increased by two-hundredths of a cent per kilowatt. That must be raking in the extra revenue, or is it to try to encourage conservation in those hot months?
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  • jms_az
    jms_az Registered Users Posts: 12 ✭
    #26
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    new forum poster here -- I'm an SRP customer looking to get solar panels.

    Anyone else have any experiences to share in the last 3 years? ticktock and jburgess -- which plans do you use?
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #27
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    So I put a 5kw system on my last house, which I now rent out. I have 1 year of results on the time of use program from 2010-2011. Hopefully this raw data will help someone figure out what plan is best. I somehow ran numbers before and determined the EZ-3 was the best plan. But after analyzing the numbers again today I'm not sure I agree with my old self.
    Attachment not found.Attachment not found.

    The reason I'm analyzing this again is I recently put a 10kw system on my new house that I'm currently in and I'm trying to figure out which plan is going to suite me best. Given my old system was only 5kw I never produced more than what I used so SRP never paid me anything for my electricity. I think with my 10kw system it will produce enough that this may no longer be the case. So my question for some of you other people out there, if I have a net surplus of say 200kwh on-peak but a deficit of say 300kwh off-peak. How much money would SRP pay me for over generating those on-peak hours? Is it less than the residential cost of off-peak electricity?

    Also for reference here are SRP's current pricing models.

    Attachment not found.Attachment not found.
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #28
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    So what is really cool is I can still login to SRP and see my old bills under that account. It looks like I switched plans because of the tool on their website and 1 year of data with a 5kw system. I'm not sure that this rule holds true for all different size systems but for a 5kw EZ3 is the best plan. I guess I'll have to wait a year to see how my 10kw system performs and run a cost analysis from their website again, unless anyone has a 10kw they want to share!?

    Attachment not found.
    5kw.jpg 112.1K
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  • WhittakerJ
    WhittakerJ Solar Expert Posts: 67 ✭✭
    #29
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?

    I created this Excel document to try and figure out exactly how much I saved using solar based off that one year. Surprisingly I'm not saving as much as I thought I would. If all my calculations are correct I only saved $522.13 with my 5kw in that year timeframe. Given that I generated 8507kwh of electricity total I don't see how the TOU or EZ3 make sense as it pertains to solar. The basic plan value of 8507kwh of electricity even at the cheapest rate 10.44c is $888. Can someone double check my math/calculations?

    Attachment not found.
    Download link to Excel calculator - https://www.dropbox.com/s/48v0q3xo8l3bwbt/Cost%20analysis%20after%201%20year%20of%20use.xlsx
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  • Dreamer
    Dreamer Registered Users Posts: 1
    #30
    Re: SRP Grid Tie: Time of Use, Easy Three, or Basic Plan?
    WhittakerJ wrote: »
    I created this Excel document to try and figure out exactly how much I saved using solar based off that one year. Surprisingly I'm not saving as much as I thought I would. If all my calculations are correct I only saved $522.13 with my 5kw in that year timeframe. Given that I generated 8507kwh of electricity total I don't see how the TOU or EZ3 make sense as it pertains to solar. The basic plan value of 8507kwh of electricity even at the cheapest rate 10.44c is $888. Can someone double check my math/calculations?

    Attachment not found.
    Download link to Excel calculator - https://www.dropbox.com/s/48v0q3xo8l3bwbt/Cost%20analysis%20after%201%20year%20of%20use.xlsx

    We installed 11kw system this June. The savings have been impressive. We have not generated more than we use, but it'll be interesting to see how things will change over the year.
    I'm also trying to figure out the optimal plan, we are on EZ3. Thank you for the informative posts!
    I'll take a look at the calculations. Is there anything else you found out since January?
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