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Comparison between gasoline and electric usage for 100 miles.

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by Three60guy, Aug 8, 2012.

  1. Three60guy

    Three60guy -->All around guy<-- (360 = round) get it?

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    I looked for a comparison between gasoline and electric costs but didn't quite find what I was looking for.

    In this comparison we will be comparing the cost of driving the Prius Plug-in for 100 miles using both gasoline and electricity. I could have done it using 50 miles for a distance but thought it would provide a better computation by reducing rounding errors etc.

    (We will use 50 mpg for gasoline as an easy comparison.)

    _____________________________________

    Prius Comparison Charging Costs for 100 miles:

    Using gas @ 50 miles per gallon means 2 gallons will be used for 100 miles
    Cost per 100 miles using Gasoline:

    Price per gallon X 2 = Cost per 100 miles using Gasoline.
    $3.50 X 2 = $7.00 (recent example)
    ____________________________________

    Using electricity @ 11 miles per full battery means you will have 9 recharges per 100 miles. (Rounded down to 9. It actually is 9.09)

    Currently my Prius charges from 3 miles left in battery to full battery in 2.5 hours. Toyota also says the Plug-in will charge in 2.5 hours. However, I have included 3 hour charges as well, in the chart below.

    Where I live in Wisconsin the following residential electric rates are available:

    Time of day Level 2 Off Peak electric rate: $.047 per kwh
    Time of day Level 2 On Peak electric rate: $.249 per kwh
    Standard electric rate: $.126 per kwh

    Therefore, the cost of using 9 recharges:

    Code:
    Nite Rate:      9 recharges x $.047 x 2.5 hours x .9kwh = $.95  for 100 miles
    Day Rate:       9 recharges x $.249 x 2.5 hours x .9kwh = $5.04 for 100 miles
    Standard Rate:  9 recharges x $.126 x 2.5 hours x .9kwh = $2.55 for 100 miles
    
    To obtain the electric equivalent price compared to gasoline merely divide the $.XX for 100 miles cost above by 2. This would give the 50 mile rate which would then compare the electric rate to the 50 miles per gallon rate of gasoline.

    Electric Nite Rate is equivalent to $.48 per gallon of Gasoline
    Electric Day Rate is equivalent to $2.52 per gallon of Gasoline
    Electric Standard Rate is equivalent to $1.28 per gallon of Gasoline

    (Prius Plug-in charge rate: .9kwh))

    Formula: Electric Rate X Charge Rate X Hours = Cost for charging car.

    Code:
    Level 2 “Off” Peak Rates            Level 2 “On” Peak Rates  Standard Rates
    1.0 Hour: .047 x .9 x 1.0 = $.04  .249 x .9 x 1.0 = $.22  .126 x .9 x 1.0 = $.11
    1.5 Hours .047 x .9 x 1.5 = $.06  .249 x .9 x 1.5 = $.34  .126 x .9 x 1.5 = $.17
    2.0 Hours .047 x .9 x 2.0 = $.08  .249 x .9 x 2.0 = $.45  .126 x .9 x 2.0 = $.22
    2.5 Hours .047 x .9 x 2.5 = $.11  .249 x .9 x 2.5 = $.56  .126 x .9 x 2.5 = $.28
    3.0 Hours .047 x .9 x 3.0 = $.13  .249 x .9 x 3.0 = $.67  .126 x .9 x 3.0 = $.34
    
    Conclusion:

    It really is best to use the cheapest electric rates you have available. As you can see there is quite an incentive to using night time rates where I live compared to using gasoline. $.48 vs $3.50 (recent). But even though you use day time rates you can see it still is cheaper than using gasoline.

    I hope I have made the correct assumptions using the calculations above. It really was an eye opener for us and we now charge at night (after 7pm) religiously.

    You can use your own electric rates and make your own conclusions by merely using the electric rates you have in your own area.

    Hope you found this useful.

    Cheers

    -
     
  2. bielinsk

    bielinsk Gremlin

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    I agree with your science. Electricity is cheaper than gas.
     
  3. Corwyn

    Corwyn Energy Curmudgeon

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    No it's not (necessarily). It is cheaper to use electricity to move your car than it is to use gas. Electricity is MUCH more efficient. Gasoline (E-10) at $3.50 is equivalent to Electricity at $0.108 per kWh, in terms of energy.
     
  4. priuskitty

    priuskitty PIP FAN

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    Since my landlord is charging me $15.00 a month to charge I figure: 11.9 EV x 31 days= 368.9 miles per month. I'm getting burned:cry:
     
  5. priuskitty

    priuskitty PIP FAN

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    of course that's assuming I charge my PIP everyday (once a day since the electricity comes on at dusk and off at dawn) sometimes I don't charge at all on some days or I still have some EV left in the "tank" so the MAX mileage I could achieve is 368.9 miles on a good month so assuming 15 divide by 368.9=.004066 times 500 ( max mpg in HV times 10 gallons)=20.33 a month for gas equivalent. that's if I would travel 500 miles in a month which I do not.
     
  6. bielinsk

    bielinsk Gremlin

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    And how is that not cheaper that gas?

    Let me rephrase.

    If you are paying less than $0.25 khw than electricity is cheaper than using gas to move your vehicle.

    I am not going to get all scientific here, but it is.

    Your landlord is ripping you off at $15 a month to charge your car. I charge about 10 a week and my bill went up maybe $12 a month, but I pay no more than $.16kwh.
     
  7. priuskitty

    priuskitty PIP FAN

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    If I could fire my landlord I Would

    LG-MS910 ? 2
     
  8. 13Plug

    13Plug Active Member

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    Great info.

    My electricity rate is $0.10610/kWh (same rate 24hrs/day + tax on top). How much will it cost for me to charge the PHV battery if "empty"?

    Is this attempt at math correct? 3.0 Hours .10610 x .9 x 3.0 = $0.286

    Still waiting to hear on my pre-order.... trying to be patient...
     
  9. 13Plug

    13Plug Active Member

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    p.s. You Yanks should switch to kilometers. The PHV is rated for 22 km city driving and 18 km highway here in Canada. Those numbers sound a lot higher than 11 LOL :)
     
  10. priuskitty

    priuskitty PIP FAN

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    not 3.0 hours, 3kw total watts is for 3.0 hours at 240 volts or 1.5 hours at 110 volts
     
  11. bielinsk

    bielinsk Gremlin

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    Reading from others with meters I hear the most it will charge is 3.2 kw. So if you have completely drained the tranction battery, it will take about 3 hours to charge the car. So at $0.10 a kwh, it should cost you about $0.30.
     
  12. bisco

    bisco cookie crumbler

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    i pay .16/kwh so about .50 to fill up. i go 15 miles for .50 or 75 miles for $2.50 vs $3.75 for gas which also takes me about 75 mile. to corwyn's point, using my reults, electricity would have to cost around .25/kwh for breakeven with gas. of course, gas is creeping back up again too.
     
  13. Corwyn

    Corwyn Energy Curmudgeon

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    3.2 kWh (kilowatt-hours is a measure of energy, kilowatts is a measure of power)

    240 Volts at (say) 25 amps = 6.0 kW (Power(Watts) = Voltage(Volts) * Current(Amps))
    6.0 kW for 32 minutes = 3.2 kWh (Energy (Watts-hours) = Power(Watts) * Time (Hours)

    120 Volts at 15 amps = 1.8 kW
    1.8 kWh for 1 hour 46 minutes = 3.2 kWh

    There are, of course, some losses here, and chargers don't run at full current for the entire time, so actual charging times will be longer.

    Costs are 3.2 kWh * $0.106/kWh = $0.34
     
    Andyprius # 1 likes this.
  14. priuskitty

    priuskitty PIP FAN

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    Well put, thanks Corwyn:)
     
  15. Yes, Thankyou. It is a problem keeping KWHrs and KW straight. I gather that KWHrs are only used when time has elapsed ???
     
  16. priuskitty

    priuskitty PIP FAN

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    correct, KW's are instantaneous ( the readings fluctuate over time) KWH's is accumilated KW's over a given time.
     
    Andyprius # 1 likes this.
  17. ProximalSuns

    ProximalSuns Senior Member

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    So the landlord is actually providing a fair deal if person would pay $12 at home or $15 at an apartment. Had to come up with some number and I'd give the landlord a tip of the hat for NOT ripping off tenants who are saving on gasoline usage and for providing a means to do it. $15 would look to be a very fair number if one had to go to a flat fee for an outdoor outlet for a tenant.
     
  18. Three60guy

    Three60guy -->All around guy<-- (360 = round) get it?

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    Yes, your math is correct. And your patience will be rewarded.

    Cheers

    -
     
  19. bedrock8x

    bedrock8x Senior Member

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    Everyone forget to amortize the battery replacement cost. So allow me to burst your bubble.
    Assuming the replacement cost of the pack is $3K ( which is low) and the number of 100% charging cycle is 3000 ( still not proven), so each charge cycle will have $3K/3000 = $1 of amortized cost.
    Each charge cycle will cost $0.286 in electricity and $1 in battery replacement hidden cost or $1.286 for 13 miles.
    BTW, 3000 x 13 miles = 39,000 mile, so the battery pack good for about 39K miles.
     
  20. Corwyn

    Corwyn Energy Curmudgeon

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    This is exactly what people said about the original Prius. Turns out, they were wrong. I am therefore willing to give Toyota engineers the benefit of the doubt, until more information comes in.

    3000 charges is over 8 years. The warranty is for 8 years or 100,000 miles. So if it fails before then it is replaced for FREE. In CARB states (where most of the Plugins are) the warranty is 15 10 years or 150,000 miles. So even if you are correct that the battery needs to replaced every 39,000 miles, the amortization should be done over 170,000 miles. In other words if one decides to replace the battery in one's Plugin at 170,000 miles, the cost per mile will be less than 2 cents.