What’s Your MPG-e?

Aptera Community Aptera Discussions What’s Your MPG-e?

Aptera Community Aptera Discussions What’s Your MPG-e?

  • What’s Your MPG-e?

  • Thomas Bushaw

    Member
    January 18, 2022 at 3:57 pm

    A commonly cited “figure of merit” for EVs is the miles per gallon equivalent (MPG-e) which serves as a useful comparison between EVs and the ages-old mpg rating for ICE vehicles. The EPA provides nominal energy costs (gasoline and electricity) for performing this comparison. Typical MPG-e values for currently available EVs range from ~60 to ~140. (See this link for additional information.)

    The MPG-e for the Aptera is ~337 (!), using the EPA nominal energy costs and Aptera’s nominal 100 Wh/mile efficiency.

    But it is more useful to use your own energy costs (local gasoline price at the pump and electrical cost, $/kWh, from your utility bill) to really see the efficiency improvement between the Aptera and your current vehicle.

    Here’s the calculation:

    • Local gasoline cost (GP) = 3.499 $/gallon (our current “best” local cost; get your value from the fuel pump at your gas station)
    • Local electricity cost (EC) = 0.0738 $/kWh (our current cost; get your value from your utility bill)
    • Aptera Efficiency (AE) = 100 Wh/mile
    • MPG-e = (GP/EC) x (1000/AE)

    For us, the Aptera would have an MPG-e of 474. We have the added advantage that we have domestic solar panels so our effective local electricity cost is about 0.0329 $/kWh. With this, the EPG-e for our Aptera would be a whopping 1,064! And neither of these even include the additional miles we’ll get when the Aptera is in the sun!

    For comparison, our 2018 Subaru Outback gets ~23 mpg.

    What would your MPG-e be?

  • John Malcom

    Member
    January 18, 2022 at 4:37 pm

    Impressive! A good calculation to make for marketing when production vehicles are in the marketplace competing with the plethora of EVs co.ing out in the next two years

  • Francis Giroux

    Member
    January 18, 2022 at 4:39 pm

    I have ordered the lightest Aptera (250 mile range) with maximum solar, plus I have a few solar panels I have collected over the years which I will mount on my house next to where I will park the Aptera, and with an inverter, plug in to the 110 volt charging port. I don’t expect to ever plug into the grid unless I go for a long trip. So using your formula:3.50/0.00×1000/100= infinite MPGe

    Dividing by zero is tough on a calculator but Hey, when your power comes from the sun you get “free energy” once the car in paid for. Excuse me, once the auto-cycle is paid for. Yeah Aptera!

  • Joshua Rosen

    Member
    January 18, 2022 at 4:41 pm

    Where do you live that your only paying 7.38 cents/KWh? I’m paying over 25 cents/KWh in Massachusetts. My generation charge is 11.4 cents, dropping next month to 10.5 cents because my town negotiated a rate. The overhead for my electricity is 14 cents, i.e. the delivery charge plus taxes and fees.

    MPGe is a silly metric that’s useful to people who don’t own an EV yet but once you are in the EV world Miles/KWh is the better way to express it.

    The CO2e number is also interesting. Here is a tool that will tell you how clean the car will be in your zip code. Aptera isn’t on it but if you use the 2021 Tesla Model 3 AWD which uses 250Wh/mile you can get the Aptera number by multiplying the Tesla number by 2.5. For example in my Zip code the 2021 Model 3 AWD is equivalent to a 155MPG car that translates into 387 MPG for the Aptera.

    https://evtool.ucsusa.org/

    • Thomas Bushaw

      Member
      January 18, 2022 at 5:35 pm

      I live in SE Washington State… fair amount of hydroelectric and wind power. Oops, my mistake — I used $0.0738 where the actual rate is $0.0739. I did not include the flat daily rate (currently $0.63 per day) or the local sales tax. No argument from me that the MPG-e number is a bit silly, particularly if you’re charging your Aptera from free sources (e.g., the vehicle itself or external solar panels). As noted by Francis Giroux above, in this situation the MPG-e → ∞.

  • Russell Fauver

    Member
    January 19, 2022 at 9:25 am

    So many different ways of calculating energy use. I like to use watt hours per mile. Seems easier to me when comparing vehicles, seems like a little finer detail. My Solectria Force uses 190 Wh/mi so when I see these newer cars using 200-350 Wh/mi I know it’s not time to trade mine in yet.

  • Tom Boucher

    Member
    January 19, 2022 at 2:40 pm

    There’s a pretty good explanation why the MPG number is a terrible number to use for improving fuel economy

    https://www.youtube.com/watch?v=oLQmwOX6Xds

    The TL/DW is that as that number gets bigger the improvement in consumption shrinks. So if you say ‘raise the fleet average by 10MPG’ as a standard vs ‘increase the 100 Miles/Gallon (or any measurement like liter as well, but this is America) I found the video interesting but I’m weird.

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