Sleepinator2000 t1_j2apthj wrote on December 30, 2022 at 9:36 PM

I'm glad you asked this question, I didn't know there was a rating, and this is super interesting to me. I had no idea that EVs were that much more efficient at converting energy, and had assumed that the benefits were something of a wash if their supporting powergrid was using coal or petroleum to generate the electricity to charge the car.

Doing a little research, it looks like the range of efficiency is 120 MPGe for a Tesla Model 3 (the best), and 68 MPGe for a Ford F-150 Lightning (the worst).

That tells me that the absolute worst electron guzzlers are still better than the absolute best internal combustion vehicles (Hundai Ioniq at 59 MPG for 2022).

Obviously there are additional environmental concerns with the original manufacture of electric vehicles, especially in coal burning countries like China, but if your electric grid is backed up by wind, solar, or hydro, this seems like a cowabunga slam-dunk.

Am I forgetting something, like power lost in transmission through a grid?

BenevolentSpline t1_j2crez8 wrote on December 31, 2022 at 7:28 AM

TLDR: Electric vehicles get way more miles per unit of energy, but not per unit of mass/volume of energy storage.

Internal combustion engines are fundamentally pretty inefficient-only about 30% of the energy they use goes to actually moving the car forward. This is related to how energy is extracted from the gasoline (research Carnot efficiency if you want to know more about the theory of how heat engines like we have in our cars work). The reason we can still make practical cars this way is that gasoline has a lot of energy packed into a relatively small mass/volume.

Electric motors have much higher efficiencies-around 90% of the energy they use goes to moving the car forward. However, the range is limited by the capacity of the battery, and the energy to mass/volume ratio for a battery is way less good than gasoline. We've only gotten the battery technology good enough to compete with gasoline on range relatively recently (especially if you consider the difference in recharge vs refill time).