Cost of Fuel Equivalent

[pelyon]

A question I'm asked every time I tell someone I've gone electric, is "how much does it cost vs a gas car?" Of course this isn't a simple answer, given all the variables involved. But I've honed it down to a short quick answer. "About half of what gasoline costs". The formula I use is as follows, using round #'s.
Assumptions: 1. cost of gas: $3/gal, 2. cost of Kwh: .27cents (PG&E, Marin Co, SF Bay Area), 3. miles per KwH: 4 (300 mile range on 75 KwH batt pack: M3, LR, AWD) 4. Avg mpg of gas car: 25 mpg.
Example: 250 mile trip, gas vs elec.
Electric takes 63KwH to drive 250 miles (250/4). 63 x .27 = $17
Gas car takes 10 Gal to drive 250 mi. (250/25). 10 x $3.00-$30

Now, I know there are other benefits of driving electric, but most folks look at the bottom line before anything else, so am hoping to open some minds to going electric. The other surprising number to come out of this, for me at least, is my equivalent mpg. If driving 250 miles costs me $17, that's the same as using 5.67 gallons of gas. 250 miles / 5.67 = 44 mpg. The sticker MPGe says I should get 116 MPGe. Not sure how the EPA/DOT got 116, but either my or their numbers are way off. Thx for reading. Feedback welcome.

 

[billh13850]

Miles per dollar and miles per gallon (and equivalent) a very different things. MPG and MPGe are strictly about the efficiency of the energy in the vehicle, not the cost of the fuel or charge. Your miles per dollar value seems about right though.

 

[Daniel in SD]

A question I'm asked every time I tell someone I've gone electric, is "how much does it cost vs a gas car?" Of course this isn't a simple answer, given all the variables involved. But I've honed it down to a short quick answer. "About half of what gasoline costs". The formula I use is as follows, using round #'s.
Assumptions: 1. cost of gas: $3/gal, 2. cost of Kwh: .27cents (PG&E, Marin Co, SF Bay Area), 3. miles per KwH: 4 (300 mile range on 75 KwH batt pack: M3, LR, AWD) 4. Avg mpg of gas car: 25 mpg.
Example: 250 mile trip, gas vs elec.
Electric takes 63KwH to drive 250 miles (250/4). 63 x .27 = $17
Gas car takes 10 Gal to drive 250 mi. (250/25). 10 x $3.00-$30

Now, I know there are other benefits of driving electric, but most folks look at the bottom line before anything else, so am hoping to open some minds to going electric. The other surprising number to come out of this, for me at least, is my equivalent mpg. If driving 250 miles costs me $17, that's the same as using 5.67 gallons of gas. 250 miles / 5.67 = 44 mpg. The sticker MPGe says I should get 116 MPGe. Not sure how the EPA/DOT got 116, but either my or their numbers are way off. Thx for reading. Feedback welcome.

EPA says a gallon equivalent is 33.7kWh which the amount of energy in a gallon of gas. It's a stupid unit.
EPA rates a Model 3 AWD at 290Wh/mi because they include charger losses. They don't include vampire/idle/whatever losses so the actual consumption is much higher. If you're charging at $.27/kWh it likely doesn't make economic sense at current gas prices. Luckily with time of use rates it's usually possible to charge much more cheaply.

 

[woodisgood]

Anywhere from a quarter (best case) to a half (worst case) of what gas costs. Biggest variables are price of electricity (and whether a person can switch and utilize a TOU plan), availability of free charging (e.g. at work), MPG and fuel requirements of comparison car, etc.

In our case, charging exclusively at home at night (13 cents/kwh) and compared to a 27mpg car that required 91 octane, our costs are 25%. And that's before you factor in oil changes and brakes, etc.

 

[Snow Drift]

Way less than half.

I pay 0.22/kWh x 75 = $16.50 (0-100%)

I pay ~$55 for a tank of 93 (I just paid $3.49 x 15.9 gal.)

You have to use 93/91, not 87, since the M3 is the cost/capability of performance sedans, not economy cars meant for low octane.

 

[Daniel in SD]

Way less than half.

I pay 0.22/kWh x 75 = $16.50 (0-100%)

I pay ~$55 for a tank of 93 (I just paid $3.49 x 15.9 gal.)

You have to use 93/91, not 87, since the M3 is the cost/capability of performance sedans, not economy cars meant for low octane.

The Spark EV only costs 0.22/kWh*20=$4.40. Tesla is way behind

 

[ewoodrick]

It totally depends on your cost of gas and cost of electricity. As well as the MPG of the car you are comparing it to. Don't forget to calculate in the cost of the oil change.

And don't forget to include the amount that you spend on Superchargers and free chargers.

 

[GolanB]

One other point I'll make here that may not have been stated, but here in NY temperature greatly impacts both charging and driving efficiency. The Aux load on the battery for heating and cooling is a real factor, and as an example, when temperatures are closer to 60 degrees, I get an average of 250 Wh/mile, but it can be as high as 450 Wh/mile when I need to run heat. On the charging side, I've seen my charging efficiency drop from 85% to about 65% at its worst, with the car burning additional energy to keep the battery warm. Although there is no separate battery heater on the Model 3, it will still draw energy. I've also been averaging about 100 miles a month of phantom drain. Doing all of the calculations including losses for temperature, charging efficiency and phantom drain, at .24/kWh costs during the winter are roughly equivalent to gas. If I charge off-peak I can get some incentives (credits) from a special program here in NY "SmartCharge Rewards" which is supposed to get me back down to about .14/kWh - I haven't yet received a check, but I'm still in my first month of service. I've been carefully monitoring my consumption using a variety of systems, the most accurate of which has been the OBD2 device I got from Fleet Carma which monitors:

Duration, Distance (mi), Electricity Consumed (kWh), Fuel Efficiency Equivalent (MPGeq), Electric Driving Efficiency (Wh/mi), Starting SOC (%), Ending SOC (%), Auxiliary Load (kWh), Ambient Temperature (F), Smooth Acceleration (%), Smooth Braking (%)

Good luck!

 

[dhrivnak]

In TN I pay $.095/kWh and gas is $2.35. A Camry at 32 MPG is $.074/mile. My 3 is $.024 or about 1/3 the cost. Against a BMW it is not even close.

 

[AlanSubie4Life]

3. miles per KwH: 4 (300 mile range on 75 KwH batt pack: M3, LR, AWD)

Yeah, for full disclosure in your calculations, assuming 10k miles driven a year, I'd definitely use 29kWh/100mi + (350kWh/yr/(10000mi/yr))/0.9 (vampire) (scaled vampire up for the charging losses).

So the AWD best case value (and quite achievable in California as long as you avoid using the heat in the winter) is 33kWh/100mi. So you're actually getting 3 miles/kWh if you charge at home.

I have a lifetime trip meter of 290Wh/mi in my P3D+ and am on target for 9000mi/yr, so my real electricity use is thus (290Wh/mi + 350kWh/9000mi)/0.9 = 36.5kWh/100mi (2.7mi/kWh)

Remember these are basically best case numbers for AWD & P3D+. It's still cheaper than gas in most cases, comparing similar vehicles, and assuming reasonable electricity costs (I'd recommend getting a cheaper rate than your 27 cents/kWh; that is outrageously expensive when charging an EV, and even in CA you may be able to pick a plan that gets you a much better nighttime rate).

 

[Knightshade]

It totally depends on your cost of gas and cost of electricity. .

Yup.

I pay about $2 for 300 miles of range in my Tesla. I used to pay about $35 for the same amount of gas in my Lexus.

This is apparently pretty cheap compared to folks in CA though.

 

[dethman]

Way less than half.

I pay 0.22/kWh x 75 = $16.50 (0-100%)

I pay ~$55 for a tank of 93 (I just paid $3.49 x 15.9 gal.)

You have to use 93/91, not 87, since the M3 is the cost/capability of performance sedans, not economy cars meant for low octane.

Takes more than 75 kwh running through your meter to charge up a 75kwh battery. Charging losses can be up to 20% in many cases.

 

[voip-ninja]

Ballparking "about half" is what I do as well, but I don't agree that you can assume getting 300 miles out of 75kw battery. For me in the wintertime the efficiency takes a big hit. Even in the summertime I get maybe 245-265 wh/m with my dual motor car and I doubt I ever get even 250 miles of real usable range out of a "full charge".

There are many other variables. My utility increases electric prices all the way up to .25/kwh in the "peak summer" period for all usage above 500kw. Doesn't really affect me as I have solar, but affects most customers who are going to add hundreds of kwh usage in the summer due to those higher rates....

For the typical customer where I live between the winter efficiency hit, charging losses, vampire drain when the car is plugged in at night and keeping warm, summertime huge rate hike, etc., it's possibly only about 30% cheaper for fuel than a similar gas car and more of a wash compared to a hybrid.

 

[GolanB]

Yup.

I pay about $2 for 300 miles of range in my Tesla. I used to pay about $35 for the same amount of gas in my Lexus.

This is apparently pretty cheap compared to folks in CA though.

How are you filling 75kW for $2? Even at commercial rates, it seems quite low. On Peak, we pay about .24 / kWh including supply, delivery and taxes. Off-peak with the right incentive program, it can drop to about .14 / kWh - even at this rate, its more than $10 to fill, before calculating charging efficiency and losses. Are you supplementing your power in some way?

 

[SSonnentag]

I just totaled up my charging and found that only 14% of my charging is done at home (100% solar or solar offset). The rest of the charging is done at the RV park where I stay during the week for work or at superchargers while traveling. In 44,000 miles I've spent exactly $5 for electricity for the car, and that was to a friend for charging at his house for a couple of hours. The RV site costs the same whether I charge or not, so I trickle charge at 12A every night.

 

[T3SMA]

i've had my MR for about 3 weeks now and haven't crunched any numbers (mostly due the fact that I'm still trickle charging and haven't set up a nema 14-50 in the garage yet). I'm still waiting on my electric bill for this cycle to see how much of a difference charging at home has been to the bill

I'm charging at work too for the time being so i guess that's considered free charging and the occasional supercharge

i've told most people that its at least half the cost of an ICE car and they are already impressed (except the hybrid drivers...)

 

[AlanSubie4Life]

How are you filling 75kW for $2?

He has some sort of crazy NC cooperative rate where he gets to pay something like 2 cents per kWh for the ~90kWh it takes to charge up his 75kWh battery. I'm sure he'll fill in the details. EVs should be selling like hot cakes over there.

 

[Gen3]

MPGe is theoretical if you assume you can extract the energy out of gas without losses. With engines being approx 30 percent efficient you get the much lower actual MPG

 

[Mdoss]

Wow. If I charge during Off-Peak hours, which I always do, my rate is $0.0588 per kWh... Yep only 6¢ per kWh !!

 

[Tummy]

My old SUV got 9 mpg city/13 highway on premium. This was the car I was driving when I first test drove a Tesla in 2013. At the time, gas was about $4/gallon. We pay $.08 per kWh in winter and $0.12 for two months in summer. Going to an EV saved us almost $5k a year. My friend has the EV rate from Georgia Power and pays $0.015 per kWh from midnight to 7am.