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electric miles are more costly than gas miles???

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by vajratlr, Nov 4, 2013.

  1. vajratlr

    vajratlr Member

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    I live in southern CA where my current rate plans are 4 tiered. Let's assume I will go to tier 3 which is $0.27/kWh. Which means to charge a PiP from empty would cost about $1.19 ($0.27x4.4 battery size). I'm not an electrician, but that seems to be the logical way to calculate the cost. For $1.19 that gets you roughly 11 miles. But with gas, using my old 2010 Prius, I get 50 miles a gallon($3.75/gallon).

    gas, it's about $0.08/mile
    eletric, it's about 0.11/mile


    What am I doing wrong here? Economically, it doesn't make sense to charge. And if gas prices fall.....
     
  2. SJ PiP

    SJ PiP Member

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    each full charge is ~3.3kwh (PiP prevents full chg/dischg).

    with my tiered rate plan, electric charge $/mi can be more than gas $/mi when all these conditions are met...
    - toward the end of a billing cycle when i'm in higher tiers
    - middle of the day "peak" hours
    - "summer" six months of the year (in "winter" six months, pretty much always cheaper than gas)

    whenever the $/mi is close, i like to charge anyway to save on ghgs!
     
  3. Tracksyde

    Tracksyde Member

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    a full charge on a PiP is more like 2.9kWh* because its usable battery capacity is only about 65% of the 4.4kWh (85% when full and 20% when the engine comes on).. just call it 3kWh.. at $0.27 per kWh, its more like $0.81 per charge to go about 12 miles.. multiply that by 4 (assuming you get 48MPG on gas and for ease of calculation) and that would be about $3.24 per gallon



    * you can read all the threads about charging losses.. but this number doesnt include charging loss.. which can be 10-15% from the wall to the car
     
  4. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    [just noticed other replies while I was typing]

    First off it doesn't take 4.4 kwh to get a full charge...you need only about 2.7 to 3.0 kwh. (about 2/3rds of your 11c/mile or 7 cents)

    And, yes you only will get about 11 miles for that charge...when driving at freeway speeds.
    But you will get 10-30% more when driving at slower speeds, either because that is where your trip takes you or on your way to the onramp. Especially during the normal gas warmup period you might only be getting 25 - 35 mpg on gas.
    So a good strategy is to use EV on side streets and short trips or for the first mile or two going to a freeway. Then once you are on the frreway or almost there with no stops, manually switch to HV. This use of youir EV miles will boost your HV mpg (eliminates most of the warmup penalty). Now, once the ICE is warm, depending on your specific trip you can switch back to EV or not. If you do switch and are going >62 mph you will be in EV boost, where you'll be using both EV and gas.

    You can also see if you can get TOU metering and lower your night rates.

    Mike
     
  5. fuzzy1

    fuzzy1 Senior Member

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    You need a different rate plan. What other plans does your utility offer? Do they have a special plan for EVs?
     
  6. vajratlr

    vajratlr Member

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    yes, SCE has two other electric vehicle plans. I called them and they do not recommend switching to a different rate plan because of the EV range being only 11 miles. But I guess I'd possibly save about half the cost by going to a different plan but it requires a separate meter. But the installation cost would cost more than the savings. With the current PiP, I would have to drive it for probably 5 years or more in order to break even.
     
  7. El Dobro

    El Dobro A Member

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    You can do what I did to offset the car charge by putting powerstrips on stuff you don't need plugged in all the time. I have cable boxes, TVs, the microwave, etc. on the strips, so when we're done with it, off it goes. It made a difference.
     
  8. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    At $0.27/kwh every watt you save (that is on 24/7) you will save you $2.36/yr. Assuming you'd like ~4 year payback and you figure out how to shut off 50 watts all the time, that is worth about $500 of expenses. That buys a lot of efficient lights, or a portion of a new fridge, ~half of a large energy star 6.0 HDTV.

    And 50 watts 24/7 gives you 36 kwh per month to charge your PIP. That is about 12-15 charges per month.

    Mike
     
  9. john1701a

    john1701a Prius Guru

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    REGEN hasn't been mentioned yet. It's better than with the regular model. The result is a little bit more electricity.
     
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  10. wjtracy

    wjtracy Senior Member

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    Yes, if your electric rates are high eg; approx. $0.24/kwhr then you are break even on fuel cost.
    Most places except NYC/LI and CA are much lower elec rates, so saving on fuel cost is easier.
    CA you get HOV access and tax credit for PiP, as incentives....and CARB warranty.
     
  11. bisco

    bisco cookie crumbler

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    someday, gas will probably go up. maybe. then you'll be in the catbird's seat.:cool:
     
  12. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Use EV miles when gas mileage would suck. Yea, use it on those short trips or low speed city traffic.

    That's when electricity is worth considering the slow refuel speed. Electric miles in PiP is cleaner than the 50 MPG gas engine, significantly with CA electricity.

    For me, EV miles cost slightly less than gas miles in NY.
     
  13. kwintone

    kwintone Junior Member

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    Glad to have a photovoltaic system...

    Yesterday produced 8.26 kWh and consumed 7.03 kWh for a net of 1.22 kWh. Estimate PiP responsible for 2.84 kWh (or 40%) for this interval. Have PiP set on timer, typically charges between 0100-0400 (set to end by 5am).

    Today produced 8.27 kWh and consumed 14.57 kWh thus far for a net of -6.30 kWh. Estimate PiP responsible for 2.97 kWh (or 20%) for this interval. Hmmm, someone must have moved the thermostat last night...

    Use PG&E NEMS (Net Energy Metering Service) and last billing cycle was $0.02/kWh. So, guess that would work out to $0.06/mi for charing at home. And glad to have an employer who provides free charging for the commute home.
     
  14. Emcguy

    Emcguy Member

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  15. fuzzy1

    fuzzy1 Senior Member

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    I'm jealous. With the coming of winter clouds and fog and longer tree shadows, mine hasn't that good a day since 11 days ago.

    But last week my young system (5 months for the starter portion, 1 month for the expansion) did cross the 1 MWh milestone, and just might keep my all-electric house in the bottom tier for another billing cycle.
     
  16. chesleyn

    chesleyn Active Member

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    I live in SoCal and I'm on Edison's standard rate plan. You are incorrect on your calculations. I don't have my spreadsheet in front of me, but I did post the rates last year. With gas at $4 a gallon, even at Edison's top tier, you are still paying less per mile than gas.


    iPad ? HD
     
  17. Michael33

    Michael33 Member

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    I think that looking at consumer cost alone misses the point. Those EV miles are nearly-carbon-free miles, miles that aren't exposing people to your exhaust fumes, and miles that promote alternatives to ICE-only transportation. If consumer cost alone is your basis for driving a given vehicle, then a 10 year old Honda or Toyota compact is your cheapest option. If trying to 'be the change you wish to see' matters, then a PHEV is the easiest way to do that.
     
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  18. giora

    giora Senior Member

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    For sake of perspective I will give you mine.
    My gas miles are 4.4 times more expensive than electric miles, and this is because gas is heavily taxed in Israel.
    Rough calculation:
    Gas is $2.2 per liter, a charge is saving me roughly 1 liter (22 to 26 km depending on weather) and cost me $0.5 (for 3 kWh).
    I assume when EVs and PHVs become more popular, the government will do something about it (gas tax is a considerable income in the national budget).
    Off topic.
    I calculated that the PIP in Israel is returning the extra investment over a regular prius (taking into account projected resale value of the two) in a bit less than 3 years when charging 400 times a year! (which is easily achievable).
     
  19. kwintone

    kwintone Junior Member

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    November is my last "good month" until the spring, where my average kWhs/day dips down to 4-6. Nov-12 average was 10.5 kWh per day followed by Dec-12 average of 4.2 kWh per day. Dec/Jan and Jul/Aug are the consistently the lowest production months (not enough or too much). Live in Sacramento area.


    Very Nice!
     
  20. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    Not sure if someone else already mentioned it, but if you do many short trips you can save a lot where the warmup penalty can be pretty high in a regular Prius.
     
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