Fun with math, the gasoline equivalent price

Retired, I can give test drives in our plug-in hybrids so I gave one to a pharmacists at Propst. The problem is how to explain the difference in cost of EV versus gasoline miles? A simple formula gives the EV equivalent to the local gasoline cost:

• $EV/gal = (MPG/100) * $/kWh * kWh_per_100mi
  
  MPG - found at http://www.fueleconomy.gov
  $/kWh - local cost of electricity, $ per kWh
  kWh_per_100mi - found at http://www.fueleconomy.gov

So this is what three popular, plug-in hybrids cost in EV mode:

• $1.05/gal - 2017 BMW i3-REx
• $1.13/gal - 2014 BMW i3-REx
• $1.30/gal - 2017 Chevy Volt
• $1.35/gal - 2017 Toyota Prius Prime

"Driving around town in a Prime is like buying gas at $1.35/gal." Local gasoline costs ~$2.00/gal for the Prime and ~$2.20/gal for the BMW i3-REx.

What is fascinating, the local cost of gasoline plays no part in the calculation. It is solely based upon MPG and local utility rate. Sad to say, it does not work for pure EVs because they have no MPG component. However, if you have a second, gas car as backup for the EV, use its MPG.

Bob Wilson

That's a good way to look at it Bob
I've always used a cents/mile comparison
An EV costs ~3-4 cents per mile for energy
An ICE vehicle costs ~6-7 cents per mile, or about 2X what an EV costs.
These numbers compare well with your $/gal analogy.

The math becomes more difficult when you consider any free charges that occur. I bought a CPOE 2015 i3 and got my one year of free EVGO charges but the 2 DC chargers near me don't even request a card to charge up in 20 minutes or so.

In fact, since I bought my car 2 weeks ago, I have put a total of 2KWh of juice into it at home just to make sure the 110V charger worked. Otherwise, 100% free energy for me so far. A hotel about a mile from my house has a charger (Level 2 only) and they actually told me it's cool for me to charge there as long as I don't leave the car for a long time. So I'll drop it off, top off to 100% and walk a block or two away to Target for my necessaries, then walk back with a bag or two and drive home.

I also have 6 different work locations now that all have EV chargers and not a single other EV driver present. So I top off to 100% whenever I am on-site.

According to the last 4 years of driving history (per tax logs), I may actually end up driving 100% free for the next 4 years unless I go visit family out of the main urban area i live in. But one of my family members lives near a Kohl's that happens to have a free Level 2 so I am thinking I could "meet them at the mall" for a bit and get topped off there.

My tax attorney/CPA has no idea what to do about the mileage tax credits on an EV because it seems ridiculous to get a 53.5c per mile write-off when the car is likely not costing me anywhere near that.

CaptainABCD said:

My tax attorney/CPA has no idea what to do about the mileage tax credits on an EV because it seems ridiculous to get a 53.5c per mile write-off when the car is likely not costing me anywhere near that.

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Just wait a few months until you'll need a set of tires.

gt1 said:

Just wait a few months until you'll need a set of tires.

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Probably true but I also drive like an old man (averaging 6.2miles/kWh right now) and I also don't put many miles on the car (average trip is under 7 miles, longest trip is 12 miles). Will be interesting to see how long those things last me.

6.2m/kWh is fantastic. Do you ever exceed 30MPH?

Actually haven't broken 47mph yet lol. All my routes are optimized for distance first and time second. The fastest routes are 40% longer by highway but only a minute or two.

Going to try my first long haul which lucky for me has DC chargers at each end practically so I'm interested in seeing what highway driving does to that 6.2 average.

My most common drive actually hit 6.4 for the trip but once a week I have a 5.8 round trip because the road gets up to 45mph.

I really wonder now if the i3 is the perfect car for me. Actually picked my folks up at the airport and magically got 2 30" suitcases and 3 carry-ons in the car. And still had a bit of space left.

I think that there is a huge market for people to use a car with the range of our i3 cars, but they just don't know it. There is so much misconception and incorrect info out there. Obviously, where you are will make a difference. Some places have installed lots of EVSE and CCS units, so charging and longer distances is easier. But, even Tesla's owners are worried about their superchargers when the Model 3 starts coming off of the production line, even with the planned additions. I bought mine since the vast majority of my travel is short range, short enough to tax an ICE which the EV just eats up with no complaints and risk of muffler going holy, or polluting the oil, or, well, you know what I mean. But, even with few places to charge away from home, nearly all of my driving is done with my i3. The thing works. Someday, I'll convince myself that I should just rent a car for those few times I might need one, verses letting my ICE sit in the garage with a battery maintenance charger on it so it could be started.

Difficult to work out the gasoline equivalent price for our BEV. Probably zero.

Our place has 10kW of solar panels and yearly runs kWh, dollar positive including the charging of the i3 at home. We rarely charge away from home.

Our PV system has been in for nearly 6 years, and we have paid back the capital cost (all paid from export remuneration) and the significant savings compared to previously 100% imported electricity.

Because of our now effective negative cost of electricity, the cost of owning and running an i3 is for maintenance items only and capital value reduction if we ever trade it in. Our ongoing costs for the i3 is the registration and insurance, occasional service and potential tyres etc.

Most people don't seem to understand that the costs of their vehicles can be wildly reduced when they make a non-fuelled vehicle choice at trade-in. When the general public finally get wind of it, the resale value of EV's will improve.

CaptainABCD said:

. . .
My tax attorney/CPA has no idea what to do about the mileage tax credits on an EV because it seems ridiculous to get a 53.5c per mile write-off when the car is likely not costing me anywhere near that.

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Thank the next SUV, pickup, or service van owner the next time you meet one. Their cars set the the rates.

When I had an ordinary Prius, two trips from the off-site office to the base paid for my commuting gas for the week. A third trip covered all of the rest of the miles for the week. I felt not the least regret.

Bob Wilson

My tax attorney/CPA has no idea what to do about the mileage tax credits on an EV because it seems ridiculous to get a 53.5c per mile write-off when the car is likely not costing me anywhere near tha

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t.

Well, your car depreciates like crazy. 53.5 cents per mile may not be enough to cover it

theothertom said:

My tax attorney/CPA has no idea what to do about the mileage tax credits on an EV because it seems ridiculous to get a 53.5c per mile write-off when the car is likely not costing me anywhere near tha

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t.

Well, your car depreciates like crazy. 53.5 cents per mile may not be enough to cover it

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Amen to that. Local dealer offered me a never titled 2016 i3 BEV for $42K. I told him that if I purchased it, drove around the block and traded it in, I'd be lucky to get an offer of $25K.