5 ms·

Nit: It seems backwards to measure efficiency in terms of kwh/mile. One would expect a higher efficiency value to be better.

oxplot 4y ago
The best metric I can think of is expected lifetime miles driven over total cost of ownership. But I don't get why you think it's backwards! You want kwh/mile to be low. Basically, you want to use as little amount of energy stored in your battery to drive a mile. That's what that is.
foobarbecue 4y ago
I agree. The equivalent of mpg is miles per kWh. Using the reciprocal is confusing.
- osigurdson 4y ago
  How about MPJ (Meters per Joule) since it is close to MPG - though the numbers would be tiny. Maybe km per GJ is more appropriate.
  - alkonaut 4y ago
    The distance-per-energy is numerically backwards compared to the energy-per-distance. This is important when e.g. wondering which car to replace, calculating a fleet average consumption and so on and so forth. For example: "Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg"? There is good reason that the rest of the world uses the opposite system, and the reason isn't just that no one else uses gallons. It's that it's an objectively worse way of communicating fuel consumption in every single way that matters.
    - osigurdson 4y ago
      >> "Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg" I'm surprised such questions come up often. Usually a current vehicle gets x MPG and a new one might get y. We use l/100 km in Canada. I think the primary advantage is it relatively easy to compute number of liters needed on a longer trip. It isn't super important however - better just to fill up! PS I was mostly kidding about using MPJ. The numbers would be tiny and hard to make sense of.
- xxpor 4y ago
  99% of the world uses L/100km to measure efficiency, so they're used to it.
alkonaut 4y ago
While the article has a US focus, the most common measurement globally is L/100km. The sensible efficiency measurement is consumption per distance, like L/100km. The electric switchover is This is an opportunity for places like the US to switch its measurement of choice too. I don't expect it to become a metric one, but at least one that works numerically (e.g. for fleet averages).
- dragonwriter 4y ago
  > The sensible efficiency measurement is consumption per distance No, that’s a sensible inefficiency measure. A sensible measure of X increases with X.
- Invictus0 4y ago
  I don't care that it's more common the other way, it doesn't make any sense in a sentence. When we talk about efficiency verbally, we say that higher or more efficiency is better: but the numerical value is better if it is lower. Miles per kWh seems like the appropriate unit to me.
dm319 4y ago
I think it makes more sense to give figures for consumption rather than distance/energy, as we're usually more interested in how much fuel it will cost us to travel a certain distance. Bit like going into a sweet shop and having all the sweet's price as "100 per dollar" or "35 per dollar" etc.. It also helps to compare costs, as 20mpg is far less efficient to 30pmg than 30mpg is to 40mpg, but the numbers suggest the difference is similar.
mqus 4y ago
They probably do not measure "efficiency" but "power usage" or "cost". Those go up as you would expect. I also have not really heard a l/100km value called an "efficiency" metric in german. It's lmost always fuel usage.

oxplot 4y ago

The best metric I can think of is expected lifetime miles driven over total cost of ownership. But I don't get why you think it's backwards! You want kwh/mile to be low. Basically, you want to use as little amount of energy stored in your battery to drive a mile. That's what that is.

foobarbecue 4y ago

I agree. The equivalent of mpg is miles per kWh. Using the reciprocal is confusing.

osigurdson 4y ago
How about MPJ (Meters per Joule) since it is close to MPG - though the numbers would be tiny. Maybe km per GJ is more appropriate.
- alkonaut 4y ago
  The distance-per-energy is numerically backwards compared to the energy-per-distance. This is important when e.g. wondering which car to replace, calculating a fleet average consumption and so on and so forth. For example: "Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg"? There is good reason that the rest of the world uses the opposite system, and the reason isn't just that no one else uses gallons. It's that it's an objectively worse way of communicating fuel consumption in every single way that matters.
  - osigurdson 4y ago
    >> "Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg" I'm surprised such questions come up often. Usually a current vehicle gets x MPG and a new one might get y. We use l/100 km in Canada. I think the primary advantage is it relatively easy to compute number of liters needed on a longer trip. It isn't super important however - better just to fill up! PS I was mostly kidding about using MPJ. The numbers would be tiny and hard to make sense of.
xxpor 4y ago
99% of the world uses L/100km to measure efficiency, so they're used to it.

alkonaut 4y ago

While the article has a US focus, the most common measurement globally is L/100km. The sensible efficiency measurement is consumption per distance, like L/100km. The electric switchover is This is an opportunity for places like the US to switch its measurement of choice too. I don't expect it to become a metric one, but at least one that works numerically (e.g. for fleet averages).

dragonwriter 4y ago
> The sensible efficiency measurement is consumption per distance No, that’s a sensible inefficiency measure. A sensible measure of X increases with X.
Invictus0 4y ago
I don't care that it's more common the other way, it doesn't make any sense in a sentence. When we talk about efficiency verbally, we say that higher or more efficiency is better: but the numerical value is better if it is lower. Miles per kWh seems like the appropriate unit to me.

dm319 4y ago

I think it makes more sense to give figures for consumption rather than distance/energy, as we're usually more interested in how much fuel it will cost us to travel a certain distance. Bit like going into a sweet shop and having all the sweet's price as "100 per dollar" or "35 per dollar" etc.. It also helps to compare costs, as 20mpg is far less efficient to 30pmg than 30mpg is to 40mpg, but the numbers suggest the difference is similar.

mqus 4y ago

They probably do not measure "efficiency" but "power usage" or "cost". Those go up as you would expect. I also have not really heard a l/100km value called an "efficiency" metric in german. It's lmost always fuel usage.