KWH cost vs gallon of gas

[CurtW]

I see a lot of discussion about cost of electricity vs cost of gas. The comparison that resonates best with me, is how does my KWH cost compare to what price per gallon I would pay if I were pumping gas instead? Here is my 2 cents worth:

There are so many variables involved, that nothing is concrete. but these benchmarks seem to work pretty well for my calcs.

I've calculated:

• In coldest weather, $1.00 per KWH is about the same as $6.00 per gallon gas.
• In ideal driving conditions, $1.00 per KWH is closer to $4.80 gasoline.

** These calcs are based on performance of my personal ICE and BEV vehicles, and I used $1.00 per KWH to keep the math simple.

I'm paying between 14 and 45 cents per KWH, so I believe my EV power costs compares to a range from a LOW of 67 cent gas (0.14 X 4.80) to a HIGH of $2.70 (0.45 X 6.00) gas. Most of my charging is at home, at the 14 cent rate, keeping me, for comparison, well under a dollar a gallon most of the time.

If you've made similar calcs, I'd love to see what you came up with, always looking to improve my math!

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[RickMachE]

Weird math.

3 miles per kilowatt hour in summer, at 14 cents (lets round to 15 cents), equals 5 cents a mile.

If a gallon of gas is $3.25, then a car would have to get $3.25/.05 = 65mpg to be the same cost per mile.

If your car gets 22 mpg, then driving an EV is 1/3 the cost (22/66).

Proof:

100 miles in EV is 33.3kWh, cost of .14 x 33.3 = $4.66
100 miles at 22mpg is 100/22 x $3.25 = $14.77

$4.66 / $14.77 = 31.5%

Many people don't get 22mpg, they get closer to 18 or 19.

 

[DevSecOps]

It all depends on where you live and it's too difficult to compare everywhere in the country equally. For example, in California PG&E electricity rates in the summer are a minimum of $0.42 per kw.

Then there's gonna be, "well I have solar so it's free..." Well not really. Solar often has long payoffs, or large investments, but no one wants to talk about that.

Then there's the whole issue around DCFC vs home charging. Additionally, there's vehicles like the prius that get over 50mpg and no one wants to talk about that either because it doesn't fit the narrative.

Gas is gas, with the only variable being your zip code.

Let me solve this hard problem for you:

-- In some areas, with some vehicles, gas is more. In other areas, with other vehicles, EVs are more. --

Happy?

 

[Maquis]

A gallon of gas is 33.7 kWh. That's the correct way to compare the energy cost. So $0.10 per kWh = $3.37 per gallon.

What makes an EV advantageous is more related to its superior efficiency, not the cost of fuel.

 

[superdave80]

and I used $1.00 per KWH to keep the math simple.

That is way, way too high of a cost for electricity.

 

[A-A-Ron]

A gallon of gas is 33.7 kWh. That's the correct way to compare the energy cost. So $0.10 per kWh = $3.37 per gallon.

What makes an EV advantageous is more related to its superior efficiency, not the cost of fuel.

That’s the most unhelpful way to look at it imaginable

 

[superdave80]

A gallon of gas is 33.7 kWh. That's the correct way to compare the energy cost.

This number gets floated around a lot, and it is technically accurate, but has little meaning in the real world. EVERY gallon of gas has 33.7 kWh of energy, but depending on which vehicle you put it into, you will get vastly different miles driven out of it. The only variables that matter in comparing ICE to EV are:
-MPG
-$/gal
-mi/kWh
-$/kWh

 

[Maquis]

This number gets floated around a lot, and it is technically accurate, but has little meaning in the real world. EVERY gallon of gas has 33.7 kWh of energy, but depending on which vehicle you put it into, you will get vastly different miles driven out of it. The only variables that matter in comparing ICE to EV are:
-MPG
-$/gal
-mi/kWh
-$/kWh

You deleted the part of my post you quoted that confirms what you are saying. ??‍

 

[ThatGuyLando]

Too many variables.

I have a mini-van (14 odyssey) that once I'm on the highway I can get like 24-26mpg. We RARELY use it since we got the mach-e. The (maybe) one time a month I go to fill it up, it immediately costs a whole month of charging at home for my mach-e (according to my chargers calculator).

Having the BEV for us is a no-brainer and I'm saving a shit-ton of money on gas, even with the monthly payment, I'm pretty much breaking even on what I'm saving on gas.

 

[SnBGC]

This number gets floated around a lot, and it is technically accurate, but has little meaning in the real world. EVERY gallon of gas has 33.7 kWh of energy, but depending on which vehicle you put it into, you will get vastly different miles driven out of it. The only variables that matter in comparing ICE to EV are:
-MPG
-$/gal
-mi/kWh
-$/kWh

True.
However, wouldn't it be convenient if we could compare two identical cars. One with an ICE and the other as a BEV. Like say a 2017 Ford Focus? The Ford Focus Electric gets 4 mi/kWh on average over 50k miles.....and just so happens to have a 33.5 kWh battery pack which is nearly a full gallon of energy (however it isn't all available to the operator so a mute point...,)
I didn't own an ICE version but a quick Google says 31 mpg combined.

 

[devmach-e]

A gallon of gas is 33.7 kWh. That's the correct way to compare the energy cost. So $0.10 per kWh = $3.37 per gallon.

What makes an EV advantageous is more related to its superior efficiency, not the cost of fuel.

If you are looking at operating costs, the correct way to look at is the per-mile cost, not the fact that a gallon of gas contains the equivalent of 33.7 kWhs. We already know that a Mach-E is somewhere between 2 and 6 more times efficient that an ICE powered vehicle. That's expressed via the MPGe rating.

 

[superdave80]

33.5 kWh battery pack which is nearly a full gallon of energy

Again, this number has no real-world meaning when trying to make a comparison. Is that 33.5 kWh of gasoline energy powering a Prius or a Dodge Ram?

However, wouldn't it be convenient if we could compare two identical cars.

Um, wouldn't comparing them lead you to the conclusion that they are... identical?

All kidding aside, the only way to compare an ICE to an EV for fuel costs is to use MPG, $/gal, mi/kwh, $/kwh, and convert each vehicle to $/mile.

 

[CurtW]

That is way, way too high of a cost for electricity.

Right??!! I use $1.00 as a benchmark, simplifies the rest of the math. I always compare to the actual cost, not to $1.00. So, if $1.00 per KWH = 6.00 per gallon, then 45 cents per KWH = 0.45 X 6.00 = $2.70 per gallon. Pretty easy to calc that way.

 

[jay1122]

The comparison depends on all the different factors that is region and car specific. Just calculate the actual $$ to see the difference. Did it so many times trying to see $$ savings vs ICE competitors when shopping around.

For EV, Annual mileage/Average Efficiency x Cost per KWH X = Annual cost for this specific EV.
For ICE, Annual mileage/specific car MPG x Gas current price = Annual cost for this specific ICE.

Calculation Example with my current numbers:
MME EV: 22000 Miles / 3 mpKwh x $0.21 electric rate= $1540 Annual cost
ICE V6 Mustang: 22000 / 21 Mpg average x $3.3 cost per gallon= $3457 Annual cost

3457-1540 = $1917 Annual Fuel Saving.

Now to see how much gas cost has to be to match this specific EV, substitute electric final cost and calculate the gas cost. Or MPG if you are curious too.

22000 / 21 Mpg x (X) cost per gallon=1540
X= $1.47 Gas price per gallon
This means, if gas falls back to $1.47, V6 mustang will match my MME in fuel cost.

Or,

22000 / (X) Mpg x 3.3 cost per gallon=1540
X= 47.14 Mpg
This means, if a car does 47.14 MPG, the fuel cost matches my MME. Hmm, a lot of hybrids can do it. Just slower acceleration.

 

[SpaceEVDriver]

It's relatively easy to do a simple but not necessarily useful comparison. You would have to also include maintenance costs, upfront costs, various fees, etc, to get a full cost of ownership comparison.

As noted several times, to get just a cost to drive the vehicle ignoring the capital and maintenance costs, just use the cost per unit of energy ($/gallon or $/kWh) divided by the efficiency of the vehicle (mpg or mi/kWh). That gives you $/mile.

I get a combined average of 16 mpg in my Tacoma. My local fuel costs are around $3.60/gallon at about 15 mpg, so my cost is about $0.21/mile when I'm driving locally. If I compare with my road trips, then it's closer to 17 mpg at >$5.00/gallon, so >$0.29/mile.

I get a combined average of about 3.3 mi/kWh in my Mustang. My electricity costs are around $0.23/kWh, including DCFC and L1/L2 (approx. 6000 miles of DCFC-charged at $0.31/kWh and 7000 miles of L1/L2 at $0.15/kWh delivered). That's about $0.07/mile. It's actually a bit better than this because those ~6,000 miles were not all DCFC. And when I'm only driving locally, I can get up to about 4 mi/kWh on $0.15/kWh, which is about $0.038/mile.

For a more direct and fair comparison, I would have to have a 50 mpg (combined) ICE vehicle and pay no more than about $3.50/gallon to get the same cost/mile as my Mustang for combined freeway and city driving. I will not find that combination with the driving that I do. Arizona and CA freeway gas costs are too high for that to be realistic.

Table 1. Cost per mile for gasoline vehicles.

Cost of gas / gallon	$/mile, 15 mpg	$/mile, 20 mpg	$/mile, 25 mpg	$/mile, 30 mpg	$/mile, 35 mpg	$/mile, 40 mpg	$/mile, 45 mpg	$/mile, 50 mpg
$3.00	$0.200	$0.150	$0.120	$0.100	$0.086	$0.075	$0.067	$0.060
$3.10	$0.207	$0.155	$0.124	$0.103	$0.089	$0.078	$0.069	$0.062
$3.20	$0.213	$0.160	$0.128	$0.107	$0.091	$0.080	$0.071	$0.064
$3.30	$0.220	$0.165	$0.132	$0.110	$0.094	$0.083	$0.073	$0.066
$3.40	$0.227	$0.170	$0.136	$0.113	$0.097	$0.085	$0.076	$0.068
$3.50	$0.233	$0.175	$0.140	$0.117	$0.100	$0.088	$0.078	$0.070
$3.60	$0.240	$0.180	$0.144	$0.120	$0.103	$0.090	$0.080	$0.072
$3.70	$0.247	$0.185	$0.148	$0.123	$0.106	$0.093	$0.082	$0.074
$3.80	$0.253	$0.190	$0.152	$0.127	$0.109	$0.095	$0.084	$0.076
$3.90	$0.260	$0.195	$0.156	$0.130	$0.111	$0.098	$0.087	$0.078
$4.00	$0.267	$0.200	$0.160	$0.133	$0.114	$0.100	$0.089	$0.080
$4.10	$0.273	$0.205	$0.164	$0.137	$0.117	$0.103	$0.091	$0.082
$4.20	$0.280	$0.210	$0.168	$0.140	$0.120	$0.105	$0.093	$0.084
$4.30	$0.287	$0.215	$0.172	$0.143	$0.123	$0.108	$0.096	$0.086
$4.40	$0.293	$0.220	$0.176	$0.147	$0.126	$0.110	$0.098	$0.088
$4.50	$0.300	$0.225	$0.180	$0.150	$0.129	$0.113	$0.100	$0.090
$4.60	$0.307	$0.230	$0.184	$0.153	$0.131	$0.115	$0.102	$0.092
$4.70	$0.313	$0.235	$0.188	$0.157	$0.134	$0.118	$0.104	$0.094
$4.80	$0.320	$0.240	$0.192	$0.160	$0.137	$0.120	$0.107	$0.096
$4.90	$0.327	$0.245	$0.196	$0.163	$0.140	$0.123	$0.109	$0.098
$5.00	$0.333	$0.250	$0.200	$0.167	$0.143	$0.125	$0.111	$0.100
$5.10	$0.340	$0.255	$0.204	$0.170	$0.146	$0.128	$0.113	$0.102
$5.20	$0.347	$0.260	$0.208	$0.173	$0.149	$0.130	$0.116	$0.104
$5.30	$0.353	$0.265	$0.212	$0.177	$0.151	$0.133	$0.118	$0.106
$5.40	$0.360	$0.270	$0.216	$0.180	$0.154	$0.135	$0.120	$0.108
$5.50	$0.367	$0.275	$0.220	$0.183	$0.157	$0.138	$0.122	$0.110
$5.60	$0.373	$0.280	$0.224	$0.187	$0.160	$0.140	$0.124	$0.112
$5.70	$0.380	$0.285	$0.228	$0.190	$0.163	$0.143	$0.127	$0.114
$5.80	$0.387	$0.290	$0.232	$0.193	$0.166	$0.145	$0.129	$0.116
$5.90	$0.393	$0.295	$0.236	$0.197	$0.169	$0.148	$0.131	$0.118
$6.00	$0.400	$0.300	$0.240	$0.200	$0.171	$0.150	$0.133	$0.120
$6.10	$0.407	$0.305	$0.244	$0.203	$0.174	$0.153	$0.136	$0.122
$6.20	$0.413	$0.310	$0.248	$0.207	$0.177	$0.155	$0.138	$0.124

Table 2. Cost per mile for EVs

Electricity cost ($/kWh)	$/mile, 1.5 mile/kWh	$/mile, 2.0 mile/kWh	$/mile, 2.5 mile/kWh	$/mile, 3.0 mile/kWh	$/mile, 3.5 mile/kWh	$/mile, 4.0 mile/kWh	$/mile, 4.5 mile/kWh
$0.060	$0.040	$0.030	$0.024	$0.020	$0.017	$0.015	$0.013
$0.064	$0.043	$0.032	$0.026	$0.021	$0.018	$0.016	$0.014
$0.069	$0.046	$0.034	$0.027	$0.023	$0.020	$0.017	$0.015
$0.074	$0.049	$0.037	$0.029	$0.025	$0.021	$0.018	$0.016
$0.079	$0.052	$0.039	$0.031	$0.026	$0.022	$0.020	$0.017
$0.084	$0.056	$0.042	$0.034	$0.028	$0.024	$0.021	$0.019
$0.090	$0.060	$0.045	$0.036	$0.030	$0.026	$0.023	$0.020
$0.096	$0.064	$0.048	$0.039	$0.032	$0.028	$0.024	$0.021
$0.103	$0.069	$0.052	$0.041	$0.034	$0.029	$0.026	$0.023
$0.110	$0.074	$0.055	$0.044	$0.037	$0.032	$0.028	$0.025
$0.118	$0.079	$0.059	$0.047	$0.039	$0.034	$0.030	$0.026
$0.126	$0.084	$0.063	$0.051	$0.042	$0.036	$0.032	$0.028
$0.135	$0.090	$0.068	$0.054	$0.045	$0.039	$0.034	$0.030
$0.145	$0.096	$0.072	$0.058	$0.048	$0.041	$0.036	$0.032
$0.155	$0.103	$0.077	$0.062	$0.052	$0.044	$0.039	$0.034
$0.166	$0.110	$0.083	$0.066	$0.055	$0.047	$0.041	$0.037
$0.177	$0.118	$0.089	$0.071	$0.059	$0.051	$0.044	$0.039
$0.190	$0.126	$0.095	$0.076	$0.063	$0.054	$0.047	$0.042
$0.203	$0.135	$0.101	$0.081	$0.068	$0.058	$0.051	$0.045
$0.217	$0.145	$0.108	$0.087	$0.072	$0.062	$0.054	$0.048
$0.232	$0.155	$0.116	$0.093	$0.077	$0.066	$0.058	$0.052
$0.248	$0.166	$0.124	$0.099	$0.083	$0.071	$0.062	$0.055
$0.266	$0.177	$0.133	$0.106	$0.089	$0.076	$0.066	$0.059
$0.284	$0.190	$0.142	$0.114	$0.095	$0.081	$0.071	$0.063
$0.304	$0.203	$0.152	$0.122	$0.101	$0.087	$0.076	$0.068
$0.326	$0.217	$0.163	$0.130	$0.109	$0.093	$0.081	$0.072
$0.348	$0.232	$0.174	$0.139	$0.116	$0.100	$0.087	$0.077
$0.373	$0.249	$0.186	$0.149	$0.124	$0.107	$0.093	$0.083
$0.399	$0.266	$0.199	$0.160	$0.133	$0.114	$0.100	$0.089
$0.427	$0.285	$0.213	$0.171	$0.142	$0.122	$0.107	$0.095
$0.457	$0.304	$0.228	$0.183	$0.152	$0.130	$0.114	$0.101
$0.489	$0.326	$0.244	$0.195	$0.163	$0.140	$0.122	$0.109
$0.523	$0.349	$0.261	$0.209	$0.174	$0.149	$0.131	$0.116
$0.560	$0.373	$0.280	$0.224	$0.187	$0.160	$0.140	$0.124
$0.599	$0.399	$0.299	$0.239	$0.200	$0.171	$0.150	$0.133
$0.641	$0.427	$0.320	$0.256	$0.214	$0.183	$0.160	$0.142
$0.685	$0.457	$0.343	$0.274	$0.228	$0.196	$0.171	$0.152
$0.733	$0.489	$0.367	$0.293	$0.244	$0.210	$0.183	$0.163

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