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Duke Energy - Time of Use

Discussion in 'Model S: Battery & Charging' started by ctcjb, Nov 4, 2015.

  1. ctcjb

    ctcjb New Member

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    My 90D will hopefully arrive in the next month or so. In preparation, I have been trying to run the numbers on changing from the Duke Energy Residential Service to the Time of Use service. Has anyone else looked into this? It seems pretty straightforward, but I want to make sure there are no "gotchas" that I am missing
     
  2. mspisars

    mspisars Member

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    Would be interested in this info as well, I just read about Duke's Time of Use service, literally, yesterday.

    Like you, not sure if I would regret switching over because of gotchas or hidden fees.
     
  3. Cyclone

    Cyclone Cyclonic Member ((.oO))

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    Duke Energy's Time of Use schedule for North Carolina (RT) isn't worthwhile unless you have a solar array due to the peak demand charges. With my numbers, it would be a bill increase compared to now. I am unsure of SC. I suggest this thread gets moved to the Southeast Forum or Charging standards forum.
     
  4. David_Cary

    David_Cary Member

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    #4 David_Cary, Nov 5, 2015
    Last edited: Nov 5, 2015
    Wait - Cyclone. TOU is not TOU-D. The D being demand charges. I have solar and Duke paid me a lot of money to go on TOU-D for 5 years. I save almost as much from the TOU-D rate schedule as I do from the solar panels.

    TOU-D last I heard was only available to solar customers.

    TOU likely makes sense with EV owners. Remember in the calcs that all weekend is off peak. TOU is meant to be revenue neutral for the average customer. An EV puts you into the Non-average category. In the summer, you freeze the house at night a little more - and you become more Non-average. Run dishwasher at 9 pm. Timer on hot water if electric. It isn't hard. There isn't a shoulder time with TOU-D but I hit 75% off peak and 25% on. I allow the 25% because it is completely solar offset. I could probably get down to 15% (summer).

    Cyclone - look into TOU. As an aside, people look at demand as worst case. I typically hit 5 kw but I hit 15-20 at night and that is with only 20A EV charging. Solar tempers the peak demand very little - there is always a cloudy 90 degree day - and always a 30 min thunderstorm once a month even if the day was sunny. I have electric hot water, electric ovens, electric dryer, 5000 sqft a/c ed (7 tons) and 2 EVs - and I run heat pump in the winter.

    My bill averages $1200 a year. Without solar $1800. Without TOU-D $2600. I assume that TOU will get me to $1000 when my 5 years on TOU-D are up.

    Just looked at Duke "assumptions" - they assume 75% off peak which is a little aggressive for "average customer".
     
  5. Zarwin

    Zarwin Member

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    #5 Zarwin, Nov 5, 2015
    Last edited: Nov 5, 2015
    I'm on it and have been for just over a year and don't have solar. Saving about $40 a month averaged out over the year I'd estimate, though I'll need to run the numbers for specifics. Very much worth it for me though you have to be carful to not have too much concurrent demand.
     
  6. Cyclone

    Cyclone Cyclonic Member ((.oO))

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    All will vary depending on use. Saving $40/mo would mean my bill is cut nearly in half. I'll check it out, but last time, I was pointed to RT which has demand charges.

    This is the schedule I am on:
    http://www.duke-energy.com/pdfs/NCScheduleRE.pdf

    And these are the Time of Use I see available (and they have demand charges, though the first one is peak-only):
    http://www.duke-energy.com/pdfs/NCScheduleRT.pdf
    http://www.duke-energy.com/pdfs/NCScheduleRST.pdf
    http://www.duke-energy.com/pdfs/NCScheduleRET.pdf
     
  7. Zarwin

    Zarwin Member

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    #7 Zarwin, Nov 5, 2015
    Last edited: Nov 5, 2015
    I am on the first one, RT, and it works for me with the combination of the Tesla and the fact that I have some equipment in my house that runs 24/7. Not a huge draw, but always on. Some months are better than others and there is a loss of convenience with having to work around the peak times for drying cloths and using the stove. For most people it wouldn't make sense, but for me it does.

    Here is I think my biggest bill this summer compared to the same month last summer, using their comparison tool. The amount of power used is roughly the same:

    2015-11-05_10-25-59.jpg
    2015-11-05_10-26-48.jpg
    2015-11-05_10-26-31.jpg

    EDIT:

    Going back and scrolling through the bills, I over-estimated, its more like an average of $30 a month savings.

    EDIT2: also note that Duke Energy and Duke Energy(Progress) are still separate and offer different things. At the time I signed up, I requested to get this TOU plan:

    Time-of-Use R-TOU Program- - Residential-Duke Energy (WARNING: Auto-Play video, turn down the volume)

    But that is for Progress customers only apparently, not Duke Energy customers. They could do a little better on the clarification there.
     
  8. Cyclone

    Cyclone Cyclonic Member ((.oO))

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    #8 Cyclone, Nov 5, 2015
    Last edited: Nov 5, 2015
    Yeah, I only use 40-45(-ish) kWh/day. With your $0.0991/kWh vs. my $0.1056/kWh, we are talking $0.25(-ish) per day difference, then you add in any demand charges. It doesn't work for my use profile, but it could for others.

    But that was my point, each person should run their numbers b/c the demand charges may make this not work out for you if your numbers don't fit right.
     
  9. Drucifer

    Drucifer Active Member

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    Sounds like the plans have changed since I last looked.
     
  10. demundus

    demundus Member

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    Not Duke but SDGE, the ONLY gotcha that really made me aggravated was that the change takes effect on the next billing cycle. I guess that might be obvious to some, but not to me, so I charged my Tesla sparingly at normal billing rates and sucked it up for 20 days till my next cycle kicked in.
     
  11. darrenf

    darrenf Member

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    I'm on RT - Residential Service TOU in Durham (not a Progress area) without solar panels. I don't charge during peak demand metering hours. My electricity usage is pretty crazy, even without the Model S, but I just checked and last month's bill was $350 and it would have been $420 on the old flat-rate plan so I guess I was smart to make the change.

    Net savings aside, I take comfort in the fact that the marginal cost to charge my Model S is less than $0.06/KWh.
     
  12. veloaudio

    veloaudio New Member

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    Resurrecting this thread from a few years ago. Anyone look in to this lately? I call Duke and they don't recommend it for my usage but I'm going to crunch some more numbers over the next few months to double check.
     
  13. scottycs

    scottycs Member

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    I am in Charlotte on TOU. I use way more power now, and my bills are similar to what they were before. We avoid charging and doing wash, dishwasher, etc in peak hours.

     
  14. veloaudio

    veloaudio New Member

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    Good to know. Do you get hit with a high demand charge per month? What is your average kWh usage a month? Thanks
     
  15. ewoodrick

    ewoodrick Member

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    Indeed, one of the concepts of a TOU rate, not necessarily driven by the Power Company, more from the Public Utilities Commission is that the should be revenue neutral. But their definition is more along the lines of "averaged out over thousands of users" So that means that some win and some lose. And in many cases, a standard rate is more like an insurance policy than a TOU is like raw cost.

    First, many rates have seasonal changes, so make sure to look at summer vs winter usage.
    When using a TOU rate, one of the basic concepts is can you move load from one time to another. If you are going to leave everything as it is, then you don't tend to take advantage of a TOU rate. So, when charging a car, that means that you will want to delay starting charge until the lower tiers go into effect. That's not that big of an issue, since the car supports it, but what happens if it takes longer to charge than the low rate period.

    To really figure out what your cost is going to be, you need to look at what your usage is during the different hours, so that means you need something that can measure it. Knowing what your overall bill is, doesn't mean much.

    But look at what your charging requirements are. If you are using 250 wh per mile, then that's going to be 1 kWhr for every 4 miles. Looking at https://www.duke-energy.com/_/media/pdfs/for-your-home/rates/electric-nc/ncschedulers.pdf?la=en says that it will be about 8.7 cents per kWhr
    If you look at charging 10,000 miles all at home, that's about $217 per year. Is it worth it to change for $18 per month? Just look at the gas bill that you decreased.

    And caveat before people jump on. This is NOT California rates, this is Carolina rates, huge difference.
     
  16. scottycs

    scottycs Member

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    Just did a comparison wtih my bills pre and post tesla/tou for Duke in Charlotte, NC.

    Using my Aug 2017 bill vs my Aug 2016 bill (no tesla)

    Pre TOU/No Tesla I averaged 10.3cents KWH
    Post TOU/Tesla I averaged 8 cents KWH

    With a total usage of 2300KW for the month, I saved roughly $53 over the standard rate. Some months I save a little, but I have never paid more from switching to TOU.
     
  17. jorobsand

    jorobsand Member

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    @scottycs - are you on a TOU residential rate for Charlotte? Or non-residential? So far I have not seen an offering for TOU rate for Charlotte-area residential customers for Duke Energy but I may be looking in the wrong place.

    Any guidance would be appreciated.
     
  18. scottycs

    scottycs Member

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    • Helpful x 1

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