Are those numbers right? 0.4 kWh/mile is 24.85 kWh/100km compared to about 14 kWh/100km my Kia Niro EV uses.

Those numbers are saying that:

- the Cybertruck uses almost twice as much energy as your Niro EV

- the 40% efficient Prius uses about 2.5x as much energy as your 95% efficient Niro EV.

what seems off?

[delayed]

With dimensional analysis you can cancel it all the way out until it's just Newtons, which is actually just the average drag force times some efficiency multiplier.

Dimensional analysis is a superpower honestly. Even in a software engineering career it's saved me from massive issues quite routinely

Any war stories?

Requests per second, bytes per request, bytes per second should all match up very closely under dimensional analysis or something is drastically wrong ;)

Little's law is another related phenomenon that is super critical. Measuring things when the units don't match has bitten me more than once.

Concur on Little's law

Mandatory XKCD: https://xkcd.com/3038/

Also: https://xkcd.com/687/

The HP 48G / 50G provides incredible unit handling. My main use for it these days.

I'm curious if you can elaborate further? Would that make the comparison clearer, or is it just a side-note on your part?

Work (energy) is force times distance. Since we're talking about energy divided by distance, it's actually just average force.

Actually newtons are just a constant factor (3.6) compared to Wh per km, since there are 3600 seconds in a hour while there are 1000 watts in a kilowatt. For example 144 Wh/km (or 14.4 kWh/100 km) would simply be 518 N. This also means that pushing along a Tesla on the highway at constant speed is roughly as hard as holding a 50 kg weight, giving you an intuitive sense of how "hard" it is to keep things moving.

Of course, in everyday life, since we buy electricity from our utilities in kWh rather than joules, it's more convenient to talk about kWh per km (or per mile).

Thanks. Was there a particular reason I'm not grasping for noting that on the comment you replied to? Seems like a comment that could be stated about any comment tackling about energy/distance.

Actually, I guess the comment you replied to was also not really clear in it's point, so I'll blame that guy for maybe diverging from the topic somewhat :)

(not trying to be negative, really! but my brain is a bit fuzzy from being sick, so thus feeling a bit dimwitted as I ponder comments)

For comparison my cargo ebike, which is not particularly efficient, consumes about 30 Wh/mi (0.03kWh/mi) in medium assist while transporting an adult and two kids.

My road bike consumes energy bars! And fruit!

So you ride around town in a PacMan? Aren't ghosts a problem?

Just gotta always have a Power Pellet in range

What a coincidence, my cargo bike that regularly takes 50kg of cargo runs on the same stuff !

Surprisingly enough, this makes acoustic bikes less carbon efficient per unit distance than electric ones, depending on the details of your diet. Of course, once the emissions are that low, this is more a curiosity than actionable insight (beyond the typical "less meat/dairy = lower emissions").

https://www.youtube.com/watch?v=HW5b8_KBtT8

"Acoustic" bike? What is this madness?

I thought you were autocorrected badly but I guess this is a term people use?

It's a joke referencing electric vs. acoustic guitars.

Yaaa I’m vegan which helps a lot! A solar powered ebike is probably more resource efficient tho.

I get 30 miles per sandwich! Beat that EV owners! :P

What's in that sandwich though? The Cybertruck using California non-renewable energy creates 162g of CO2 per mile. A sandwich full of lamb generates 666g. A sandwich of lentils does 40g.

Haha, I've thought about it myself, but your response spurred me to dig deeper. Looks like there has been a study:

https://pure.manchester.ac.uk/ws/portalfiles/portal/63517838...

I wonder how long it would take for an EV to catch up to a bike all-in (including manufacturing materials) if the cyclist was eating something heavy on carbon footprint like a philly cheesesteak everyday.

Driving uses a lot of energy. It's wasteful if you aren't getting a good use out of it (of which just driving around to relax could me considered a good use, but of which some manager requiring RTO might not be).

Driving is not wasteful. Energy is not a scarce thing in the universe.

Using energy is not bad. Creating excess carbon emissions is bad.

You need to be able to hold two ideas in your head.