True way to calculate MPGe based on electric bill

Metal_Horses

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I'm looking for help/confirmation on my MPGe calculation.

Assuming 3.0 miles/kWh performance.

Your electric bill gives a price per kWh rate for the energy, but there no price per kWh for delivery. I see 3 components:
1) Customer charge (Flat $4.00)
2) Distributed Related Component (Based on usage)
3) Cost recovery charges (Based on usage)

In Ohio, I pay about $.04989 (Stated rate) for electricity and about $.085 for delivery (Total of 3 above charges divided my the kWh used)

So I'm constantly paying about 13.5 cents/kWh out the door.

If gasoline is currently $2.50/gallon, I can buy about 18.5 kWh's for $2.50

18.5 x 3.0 miles/kWh and I'm getting about 55 MPGe

So questions to the group:

1) Did I calculate that correctly?
2) Does $.085 seem high for delivery?

I do have 32 solar panels, which covers about 85% of my usage, but that shouldn't factor in when talking about the "Added" cost of an electric car.

Thanks.
 

phidauex

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I'm looking for help/confirmation on my MPGe calculation.

Assuming 3.0 miles/kWh performance.

Your electric bill gives a price per kWh rate for the energy, but there no price per kWh for delivery. I see 3 components:
1) Customer charge (Flat $4.00)
2) Distributed Related Component (Based on usage)
3) Cost recovery charges (Based on usage)

In Ohio, I pay about $.04989 (Stated rate) for electricity and about $.085 for delivery (Total of 3 above charges divided my the kWh used)

So I'm constantly paying about 13.5 cents/kWh out the door.

If gasoline is currently $2.50/gallon, I can buy about 18.5 kWh's for $2.50

18.5 x 3.0 miles/kWh and I'm getting about 55 MPGe

So questions to the group:

1) Did I calculate that correctly?
2) Does $.085 seem high for delivery?

I do have 32 solar panels, which covers about 85% of my usage, but that shouldn't factor in when talking about the "Added" cost of an electric car.

Thanks.
The cost numbers seem normal. Every utility adds up the per kWh charges differently (there are something like 10 different charges that get added up on an Xcel bill...), but the total of 13.5 cents / kWh sounds about right for your area.

The main problem with your MPGe calculation though is that you are comparing cost, not energy content. So you've answered a useful question (what MPG of car would the MachE cost the same amount to keep filled?), for which the answer is a 55 MPG car would cost the same to fuel as your MachE does (at today's gas and electric prices....)

However, MPGe uses the actual energy content of a gallon of gas, which is 33.7 kWhs. Redo the math comparing that to your miles / kWh, and you'll get ~ 101 MPGe, which is pretty close to the EPA calculated values (slightly better, actually).
 

tomking29

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MPGe is an interesting method of comparing the “equivalent” to gas but it’s really only about efficiency, not cost. It helps to understand the EPA’s logic that a gallon of gas produces roughly 115,000 BTUs of heat, and the “equivalent” of electricity is 33.7 kWhs (to produce the same BTUs). Because EVs are so much more efficient, a gallon of gas might propel you ~20 miles, while the “equivalent” 33.7 kWh will propel you ~100 miles. To calculate the cost, you would multiply your $0.135 kWh by the 33.7 (about $4.55). In short, most EVs are ~5x the efficiency, but 33.7 kWh is about twice the cost of a gallon of gas.

BTW - I agree with your rough estimate of $0.135 kWh (that’s close to what I pay in MI).
 
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Metal_Horses

Metal_Horses

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Thank you both
 

nhdave

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sounds like a bargain. New Hampshire rates with Eversource are .17/kwh and no incentives at all for ev.
 

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