I find these numbers really fascinating because it shows how efficient battery-electric vehicles are, especially when you think about things like incandescent bulbs, which easily will run at 50W just to light up a small room.
Don't get me started on cars that display usage in kWh/h per 100km. Yes, you read that right.
Periodically I see colleagues trying to come at work by bicycle. The longest lasting record is one and half year. All the others didn't last after the summer.
Fwiw it would take me 1h of walking to go to work or about 1h20 if I take a couple buses. Or I can take the car and be done in less than 10 minutes.
[0]: Why Canadians Can't Bike in the Winter, but Finnish people can: https://www.youtube.com/watch?v=Uhx-26GfCBU
Rain: I use rain pants and waterproof jacket/shoes. Snow: bike lanes are cleared, though I did regularly cycle on snowy roads in Germany when they were not cleared yet. Tires with some profile and experience make it very doable.
But then you wrote that you walk just 1h to work ... That can't be more than 20 minutes by bike. (My commute is 30 minutes by foot, 15 by car, 1:30h public transport... But due to the road layout it takes me just 10 minutes on average by bike.)
> Fwiw it would take me 1h of walking to go to work or about 1h20 if I take a couple buses. Or I can take the car and be done in less than 10 minutes.
That's kinda the problem. Even here with pretty good infrastructure car is 50 minutes in peak traffic, metro + walk to metro station + few stops of tram is 1h. If I go like 2h after peak it's 35 minutes...
ICEs use litres per 100km which I think is where this comes from. And I hate it. miles-per-gallon is much easier to understand I think. I wish we could have split the difference in the EU and just had km-per-litre. I'd rather know how far a tank will get me than how much fuel I'll use to travel exactly 100km
A 20 MPG car is not twice as efficient as a 10 MPG car.
http://www.mpgillusion.com/p/what-is-mpg-illusion.html
L/100km has the length and volume units reversed, which allows comparisons.
The issue is going from 30 to 20MPG is not the same change as going from 20 to 10MPG, where as the difference between 15 and 10, and 10 and 5 l/100km is the same absolute change.
They are but now I prefer .05 GPM to 20 MPG.
Everyone in the US it seems to like bigger numbers. Just look at the argument some people use to why some people prefer Fahrenheit over Celsius.
... is what I would say, but Tesla seems to be the only one using the sensible Wh/m or Wh/km. All the German ones use the nonsensical kWh/h per 100km.
Why not?
The page you linked doesn't talk about "twice as efficient", it talks about an absolute number of gallons saved per distance travelled.
Also, assuming there was no typo, vegardx's point was that "kWh/h per 100km" is invalid. "kWh/h" is the same as "kW", and "kW per 100km" (power per distance) is not describing vehicle efficiency, it's non-sensible. "kWh per 100km" (energy per distance) is.
It's just something you're used to.
> I'd rather know how far a tank will get me than how much fuel I'll use to travel exactly 100km
Well, there you go, you're comparing apples to oranges. Unless your tank is exactly one gallon, you've made a conversion when you compute how far a tank will get you. Well, we do the same thing here. I want to travel 500 km? I'll multiply my L/100km by 5 and get how much gas I need. This tells me how many times I'll have to refuel, etc.
I think the actual units used in EU are, for example, 19kWh/100km (from the BMW iX which does very well for it's size-class). You seem to have an extra /h in your figure. It has the advantage of being a understandable number, relatively well sized in scope. People can think of 100km as a reasonable length in their head that connects distant points. We tend to think in terms of kWh, which is what electricity is typically metered in world wide. It feels like a poor use of a metric system that shouldn't have a bunch of weird prefixes (there's a k above & below the divisor? are you kidding me? 100km? c'mon!!) but the units are people-sized, are things we can work with in our head. And the final number, 19, as in 19 kWh/100km, is reasonably scoped, going up if you're more efficient, going down if you're less efficient.
It's inverse from MPG, putting the range-unit is on the bottom & the energy-unit is on the top. Some people love it: they claim that the difference between like 12 & 24 MPG is hard to appreciate the savings off of, whereas the difference between 24 & 48 MPG looks big but is actually only half as much fuel saved. Personally, I don't really chalk this up as a win, but some people think it's important & I can recognize that potentially it might be helpful.
I still think we should just use 33.7kWh / 1 gallon-of-gas equivalent as the common unit of energy & give everyone a common frame of reference.
There's a lot of fuzz in the EV space since everyone is advertising WLTP (previously NADC) numbers as an indicator for range. It uses a standardized test, so this means the numbers should be comparable. But they're not. Some BEVs are much more efficient in cold weather than others, due to things like heat pumps or just better engineering, like aerodynamics. This isn't well reflected in WLTP, and people get disappointed.
You can easily argue for both kWh or Wh. I've always been a proponent of using the smallest units possible, since then everything is just addition, regardless of what you want. With everything being in units of 10, it's fairly easy to do, either way. You could argue that the logical conclusion would be to use Ws/m, which is just ... Joules/m, another SI unit. But then we're using units that most people have no fundamental understanding of.
Now let's talk about wheel size. mm/percentage/inches all in one unit...