Washington State Notes Greatest Fuel Cost Savings For An EV

JUN 26 2018 BY MARK KANE 41

Electric vehicles are more efficient than internal combustion engine vehicles, but how big of a savings can be realized? The Office of Energy Efficiency & Renewable Energy answers with a map.

Because electricity costs and regular gasoline costs varies between states, the savings of driving an electric car will vary, pretty widely.

As it turns out, the biggest savings can be made in Washington state – 74%, while the lowest is in Hawaii – 9% (the only state below 20%). The situation in Hawaii (high residential electricity rates) is especially sad, because as an island BEVs would be a perfect fit. The majority of states are above 60%.

The comparison was done using the eGallon tool, which shows how much it would cost to drive on gasoline and electricity.

Tesla Model X

“Electric vehicles are more efficient than internal combustion vehicles, but fuel cost comparisons can be complicated because the price of gasoline and residential electricity vary considerably by state. To address this, the Department of Energy developed an eGallon tool that shows the fuel cost of operating a vehicle on regular gasoline versus electricity for any given distance. Using this tool and comparing the cost difference between gasoline operation and electric operation, all states showed cost savings for electric operation. The average fuel cost savings for all states was 60% and each of the states except for Hawaii had savings of greater than 20%. The state of Washington provided the greatest fuel cost savings (74%) for electric vehicle owners. Residential electricity rates, which are high in Hawaii and low in Washington state, greatly influence the level of savings.”

The eGallon

“Note: The eGallon tool uses average state or regional gasoline prices and average retail utility electricity prices. Home based solar installations are not considered. Savings are for May 19, 2018.

Sources: Savings – U.S. Department of Energy, eGallon website, accessed May 14, 2018.

Electric vehicle efficiency – U.S. Department of Energy and U.S. Environmental Protection Agency, “Electric Vehicles,” www.fueleconomy.gov website, accessed May 11, 2018.”

source: energy.gov

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41 Comments on "Washington State Notes Greatest Fuel Cost Savings For An EV"

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Zachary Hafen

What the hell is an eGallon? I can’t find anything online showing how it’s calculated…

I live in Washington and pay about 2 cents in electricity per mile to drive my Leaf. If a gas car gets 25 MPG, that’s like buying gas for 50 cents/gallon. It’s unreal.

At $3/gallon, a gas vehicle would need to get 150 MPG to outdo my Leaf. In other words, my 4 door hatchback is cheaper to fuel than a moped.


The methodology is here:


The formula for the eGallon is: (average mpg for ice vehicles) * (average kWh/mi for EVs) * (price per kWh of electricity). They then compare that figure to the average cost of gas.

Assumptions seem to be:
– 27.9 mpg for ice vehicles
– 0.326 kWh per mile for EVs (about 3 miles/kWh)

So everything depends on the accuracy of those assumptions. My Leaf claims to do better than 3 mi/kWh even in winter, but that won’t factor in charging losses. Still seems kind of low.

The formula is more interesting to me if I switch out the 27.9 mpg average for more relevant comparisons, e.g. the car the EV replaced, the car I was considering buying instead of the EV, etc. For PHEV owners, it allows you to directly compare the cost of EV vs. HV driving.

Zachary Hafen

Nice, so with their Assumptions, the eGallon where I live is 83 cents.

My assumptions are that my Leaf does 4.5 miles per kWh, which is an average for the entire year. It probably is closer to 5.0 in the Summer and 3.0 in the Winter.


The 0.326 kWh/mi for EVs is an outdated average of the top 5 best selling EVs in 2015: Leaf, Volt, Model S, i3, and the Ford Fusion Energi. This is no longer relevant to the popular EVs today. Trying to do this on the basis of averages of multiple vehicles is likely to lead to apples-to-oranges comparisons. eg. a comparable ICE vehicle to a Model S (0.33 kWh/mi) is likely to have lower than 28 mpg and require premium gas if the performance is even worth comparing.


The key is that the 0.326 kWh/mi is already adjusted for a blended summer/winter driving model where A/C and heating are already baked into that number.

There’s an explanation in the post and a link to the eGallon calculator.



Have you seen this:


Have you contacted your local state representatives to see about applying 50 dollars of your yearly 150 dollar EV tax to provide grants for installing new DC charge stations and level 2 stations at employer locations.


I think the Governor’s office would be a better address, as they implement policies, and are also far better than the average Legislature member with respect to EVs and the environment in general.

Zachary Hafen

I was under the impression that a lot of that EV tax WAS being used to build out the fast-charging infrastructure. This one just went in from our tax dollars: http://keprtv.com/news/local/first-non-tesla-dc-fast-charging-station-in-the-tri-cities


They took a one time amount of a million dollars out the 50 dollar year to would be going to the multi-modal tax fund. Any additional funds will have to be approved my the legislators.

What I don’t get is why three DC chargers in the TriCities when Walla Walla, Wenatchee and Spokane will get none.


Two points from the egallon methodology:

It uses 27.9mpg as the average miles per gallon of Cars, excluding Car SUVs (which now make up over 50% of vehicle sales).

It uses the average of the top 5 EVs from 2015 which is 326 watt-hrs per mile.

My Model 3 is getting 235 watt-hrs per mile efficiency over 2,000 miles. My Nissan Leaf is getting 250 watt-hrs per mile efficiency over 16,000 miles.

Conclusion: the egallon calculator is understating the potential savings of running an EV compared to an ICE vehicle. As always, YOUR mileage may vary.


The “326 watt-hr / mile” used in the above map was DOE 2015 data, averaging the top 5 selling electric vehicles, including Model S/X. If you drop MX, and add back the Nissan Leaf, you get 298 for a more reasonable 2018 figure (plus MS,Bolt,Volt,Model3, using our own IEV sales data 😉 ).

The BMW i3 falls out of the 2018 group, for lack of sales. So, there was kind of a straddle between it and the Model X. Really, after a couple more years this number should fall to ~270-280.

I would much rather “Miles per KWh” reporting, instead. There, we’re going from 3, to 4.


When I got my first EV I had switched out all the lighting to led and compact fluorescent bulbs. What I have seen is with the electricity savings I use the savings to fuel the EV. Really have not seen difference in cost or KW used each month. I don’t commute so I and not having to charge a large battery daily. We now have 2 EV’s and have not really seen a significant increase in usage per month. A kw saved through efficiency or conservation is a kw to fuel the EV’s. Can’t directly do that with ICE.

When I figure in gas costs, oil changes and maintenance that an ICE requires the savings are greater than the article is claiming.


Replacing light bulbs is cute but what you should have done is instal pv…if you own of course.


LED lightbulbs can be cheaper than installing PV.


Haha…true, but it depends how many you buy.
Seriously, now…in the long run they are not cheaper. You spend $30 to get them and install them throughout your house and that’s it. I spent $12k on a pv system that will return a projected $60k over 30 years.
Light bulbs -$30
PV + $48000

Are your light bulbs still cheap now?


save $60k over 30 years? My entire electric bill is under $1500 / year even spending a dollar a day to charge my cars for my typical 30 miles of driving. How do you save $2k a year? Something seems wrong with your math unless you rates are crazy high and you have a high usage and you are generating as much as you use. I’m in central Oregon with a 3000+ sqft house.


If you are from OR you should not comment about electric rates before realizing that you are at the lowest end. Of course your savings will be less than my SoCal savings. In addition to my 22c/kWh averege rate my gas is $3.70. With these prices it’s quite easy to save $3k/year with one ev…add another and it gets even better. I was paying $2k/y in electricity alone without ev in a house half your size.


I checked into a pv system. Too long of a payback in our area. In $ saved per month the EV works best for us. I can drive an EV but cannot drive a PV. Either way would only save me about $100 a month. If I lived where electricity was expensive then a pv system would be a good investment. When PV’s get down to $2-$3 per kw installed then the payback starts to work in our area. The installation costs eat up the cheaper costs of the panels. We have a new house that is very efficient giving us a reasonable electric bill each month. Electric rates are not going up here. With all the cheap wind and solar power here, it keeps electric rates flat. New Natural gas plants are having trouble competing with renewables. Coal is dead along with nuclear in our state.

I am pro PV but economically it is not a good fit for our budget and location.

Too long of a payback at present prices.


Absolutely agree that pv installs are not the same everywhere but you should recheck your sources. Last year a friend of mine got $1.6 per kw installed in SoCal. At such prices, even if the electric rates are low, pv is still worth it. I know solar can be cheaper here than in other markets. Shop around and you may find something that’s worth it.

Ron Morrell

It is worth checking to see what the market is like in your area for Renewable Energy Credits. In addition to saving 15c/kWh, I’m also receiving 6c by selling the RECs to the utility. In 2012, I paid $24K, got $10K back from tax incentives, and am saving about $120/month on electricity (reduced use +RECs. 10 years payback = 10% ROI.
I have replaced incandescents with CFL & now as the CFLs burn out am replacing them with LEDs. In addition to savings from powering the lights, less heat leads to savings on Air Conditioning.
(Heresy, but I get a free bus pass from work (5 blocks from cross town commuter express to work front door) that saves a bundle of money too. Car-crashes and auto theft abound in Albuquerque:#1 per capita in Auto theft!- go 505!


1. Hawaii is one of the states with special EV electricity rates (currently limited to 5000 households, which I think is still more than the number of EVs in the state). https://www.hawaiianelectric.com/Documents/my_account/rates/hawaiian_electric_rates/heco_rates_tou_ri.pdf

2. Meanwhile our fair and drizzly state, while the electricity rates to gas prices ratio is indeed very good for EVs as the headline says, also competes right now for the most EV-penalizing state in terms of state incentives/fees. We pay $150/month extra in tabs, plus (for most of us) an inflated value-based tab fee that doesn’t take into account the Fed rebate and quicker market depreciation – while our EV-purchase incentive has expired last month thanks to political squabbling and/or an unholy alliance between right-wingers and purity trolls on the left.


HI also has a ton of residential pv instals. Many of these owners are also ev drivers so kWh cost is irrelevant to them.


“HI also has a ton of residential pv instals”

Eggsellent point. Perhaps no other state is there more incentive for EV drivers to add PV. PVs are only slightly more expensive in HI while electricity is more than double and you don’t have the same seasonal challenges.


34c/kWh at the house where I stayed in February…i did my best not to keep the light on too long. Oil will do that to you. Ouch!

Not that Dave

$150/month??? Wow, what state is this that you are referring to? $1800/year in EV fees? Wow!


I suspect it’s 150 dollars a year. And I believe Sound Transit uses a straight line depreciation and not actual resale value.


In my part of MA we pay over 20 cents / kWh, making the $ savings of EV driving rather modest. In fact, according to the eGallon formula, my Clarity costs about the same to run on gas or electricity. Of course, my employer doesn’t have a free gas station. Neither does my local supermarket, bank, fire station, etc.


$.24 where I am. That’s including the $129/MWh wholesale supply charge that has been in place *all year*.

Bill Howland

This ‘high efficiency’ is only true for my 2 electrics during 3 seasons…. Wintertime operation (more than 3 months where I live), is quite inefficient, seeing as both the battery AND CABIN need to be constantly heated. Due to living east of one of the great lakes, it is so humid in wintertime that heated defroster operation is mandatory to even see out the windshield.

PHEV’s shine during this time, as engine operation then becomes both cheaper to operate (the gasoline cost is less than the electricity it replaces), and much more efficient, since much more of the otherwise wasted heat is recouped.

philip d
Don’t you drive a Model S? You drive one of the most inefficient EVs one can buy. But with that trade-off you get a full size vehicle with lots of power. Are you plugging into the egallon formula the mpg from an equivalent full size vehicle with similar power rather than the standard 27.5 mpg number? Let’s assume one has a S75D and gets only 1.75 miles per kWh in the winter. And a Mercedes E400, which still doesn’t have the performance of even the lowest performing Tesla S, gets 22 mpg combined (actually less in the same cold winter). So (22 mpg) x (.571 kWh/mile) x ($.15 kWh) = $1.88 per gallon of gas equivalent. If your electricity is $.20 then it comes out to $2.55. Now if you had an S100D the performance increases to where you would have to compare it to an AMG E63 which gets 18 mpg combined. At $.15 per kWh and even assuming only 750 Wh/mile consumption at high highway speeds with the heat blasting then you are looking at an equivalent of $2 per gallon. I mean I’ve never even heard of anyone getting as bad as 750 Wh/mile even with cabin… Read more »

I’m pretty sure I read that heating using a heat pump from grid electricity is actually significantly more efficient (in terms of CO2 produced) than heating from burning fossils?

Not sure about the costs…

Bruce Sanders

As a hybrid owner (Volt), I agree with the above statistic, but caution that they probably do not take into account winter heating requirements. While the AC in my Volt is electric – a good thing – the heating system is also electric and uses a tremendous amount of energy on cold days. Don’t laugh at me, but I do keep a blanket in the car in the winter so I don’t have to turn on the heat. God bless the inventor of heated seats!! My Long Island home pays 24 cents per kw, my NYC apartment pays 33 cents per kw. Electric cars make no current sense here right now with low gasoline prices ($2.99/gallon), except for HOV running and lower maintenance (but higher acquisition costs even after tax credits – $9200 for a Volt). As for the future…time will tell.


It is based on EPA tests, and the EPA tests already are adjusted for winter/summer driving. You will outperform this number on days when the weather is perfect, and underperform on colder or hotter days.


Not sure what exactly is calculated here. In SoCal on TOU it is 12c, gas is $3.60… if you drive ICE that is math you don’t want to see. I know SD is special so they get premium electrons which are more expensive but even they can get 23c. In my neighborhood the ev drivers also have pv so there’s that.


“premium electrons which are more expensive but even they can get 23c.”

EVs run so much better on premium electrons.

Any reason solar wasn’t a big deal in SD? Here in The Bay Area you could get solar for 15c with nothing down or 12c if you financed yourself. That was before the tariffs but I would expect better production in SD being further South and having clearer weather.

I went solar 15 years ago so my system was fully paid for by the time I got an EV.


I got $2.20/w installed when i did mine but i have meet people that got under $2…which is crazy cheap because it puts the payout under 4 years. You don’t care about c/kWh unless you are leasing. I think these deals are still on even with Trump’s “help”.


Solar is all over the place in SD. My brother in law flew a drone over the neighborhood and I was shocked by how many houses have it now. Many of them can’t be seen from the street.

We were one of the first houses in the entire county to install solar back in 2001 so it’s weird (but good) to see how many have it now.

Jeff Miller

Obviously Washington State’s $150 EV registration fee is NOT being considered in this analysis.


Also not included is the $450 SoCal ev rebate from Edison…and many other similar rebates from electric utilities throughout US.


This is an overly complicated way to do a comparison that relies on finding a comparable ICE vehicle to compare to the EV. ICE vehicles vary widely in their fuel consumption and so do EVs. Why not just calculate $/100mi or $/100km? Then you can easily compare them.

eg. A Model 3 at EPA-rated 26kWh/100mi charged at $0.12/kWh would cost $3.12 per 100 mi (excluding charging losses). Compare that to whatever vehicle you like. But if you use the usual comparison of a BMW 3-series at EPA-rated 27 mpg (3.7 gallons per 100 mi) fueled with premium gas at a current US average of $3.40 for premium gas, it would cost $12.60 per 100 mi for the BMW. That’s 4-times the cost.