4 ms·

The rediculoussness of the energy use of transport is especially noticeable when you are driving a Tesla which by default shows you a dial of power consumption

The rediculoussness of the energy use of transport is especially noticeable when you are driving a Tesla which by default shows you a dial of power consumption and generation in kW. When rolling down a hill with regenerative breaking, the car is generating 50kW. You can literally power many average homes with that.

m463 3y ago
On the other hand, pedaling a bicycle, or pushing a car is a lot of work. It's not ridiculous until you compare against people doing it manually. also, teslas are really quite efficient and it's amazing how they recover energy as well. I wonder if there are efficiencies to be had recovering energy to come, since they can only recover what the batteries can absorb.
- 4gotunameagain 3y ago
  Pedalling a bike is not a lot of work. Old people do it daily. Thrusting a car through air at 100kph though, that takes a lot of work. Drag scales with the square of the velocity and proportionally to the frontal surface area. Cars are a fast, but woefully inefficient means of transport.
  - sokoloff 3y ago
    > Drag scales with the square of the velocity Drag force scales with the square of velocity. Drag power (rate of work or rate of energy consumption) scales with the cube of velocity.
    - 4gotunameagain 3y ago
      Good clarification thanks !
  - TheSpiceIsLife 3y ago
    Perhaps you've never cycled up a hill.
    - 4gotunameagain 3y ago
      Perhaps I've grown up in Europe and have been cycling my whole life.
      - bee_rider 3y ago
        You could be from Denmark
        4gotunameagain 3y ago
        I'm not, I've just lived there ;)
- deleted 3y ago
  [deleted]
- imoverclocked 3y ago
  You lose a lot of energy to drag, friction and resistance(aka: heat.) Battery capacities are almost never the limiting factor in this equation. This is especially so when you don’t top the battery off to begin with.
- stefan_ 3y ago
  Of course it's ridiculous to have 300kW car engines racing from light to light averaging 10mph in the city when someone on a bike can do that faster with 100W.
  - IMTDb 3y ago
    Only if the lights are stopping the car but not the cyclist. If you apply regulations that are designed to favour one contestant, it's not longer a fair comparison.
    - rented_mule 3y ago
      I walked to work for over a decade before I retired. I stopped at all the red lights and beat the cars most days. Bikes and pedestrians can go much faster than cars between lights when traffic is bad enough. Sure, there is favorable treatment (pedestrians get their own "roads" and bikes can drive between lanes), but there is no similar treatment that would make sense for cars because they are too big and insufficiently nimble.
    - ornornor 3y ago
      If anything, bicycles are very rarely (in some places, never) favoured over cars in urban planning/design.
  - m463 3y ago
    300kw is peak power. I think teslas are pretty efficient: https://forum.abetterrouteplanner.com/blogs/entry/22-tesla-model-3-performance-vs-rwd-consumption-real-driving-data-from-233-cars/ https://forum.abetterrouteplanner.com/blogs/entry/22-tesla-m... A model 3 LR uses less than 100 watt hours to go 1 mile at 25mph I wonder how efficient bikes become at higher speeds with respect to drag coefficient (without a streamlined fairing)
- contravariant 3y ago
  > On the other hand, pedaling a bicycle, or pushing a car is a lot of work. One of these is not like the other. Pedalling a bike doesn't come even close. Humans consume several million calories per day at most, now as a rule of thumb a million calories is about the same as a kWh. And the only reason they consume that much energy is because the human body is inefficient at converting this heat to work. Even the best cyclists struggle to produce anything more than a few hundred watt. More to the point, humans struggle to power a light bulb, let alone a house.
  - Wicher 3y ago
    > And the only reason they consume that much energy is because the human body is inefficient at converting this heat to work. The human body does not convert heat to work. We do something entirely different (look up the "ATP/ADP cycle"). But yeah there are certainly conversion losses in the conversion of egg sandwiches to labor. 25% or so. Which is actually pretty good; you won't be able to match that with a steam machine built over the weekend (start with solving the problem of setting eggs on fire?).

m463 3y ago

On the other hand, pedaling a bicycle, or pushing a car is a lot of work. It's not ridiculous until you compare against people doing it manually. also, teslas are really quite efficient and it's amazing how they recover energy as well. I wonder if there are efficiencies to be had recovering energy to come, since they can only recover what the batteries can absorb.

4gotunameagain 3y ago
Pedalling a bike is not a lot of work. Old people do it daily. Thrusting a car through air at 100kph though, that takes a lot of work. Drag scales with the square of the velocity and proportionally to the frontal surface area. Cars are a fast, but woefully inefficient means of transport.
- sokoloff 3y ago
  > Drag scales with the square of the velocity Drag force scales with the square of velocity. Drag power (rate of work or rate of energy consumption) scales with the cube of velocity.
  - 4gotunameagain 3y ago
    Good clarification thanks !
- TheSpiceIsLife 3y ago
  Perhaps you've never cycled up a hill.
  - 4gotunameagain 3y ago
    Perhaps I've grown up in Europe and have been cycling my whole life.
    - bee_rider 3y ago
      You could be from Denmark
      - 4gotunameagain 3y ago
        I'm not, I've just lived there ;)
deleted 3y ago
[deleted]
imoverclocked 3y ago
You lose a lot of energy to drag, friction and resistance(aka: heat.) Battery capacities are almost never the limiting factor in this equation. This is especially so when you don’t top the battery off to begin with.
stefan_ 3y ago
Of course it's ridiculous to have 300kW car engines racing from light to light averaging 10mph in the city when someone on a bike can do that faster with 100W.
- IMTDb 3y ago
  Only if the lights are stopping the car but not the cyclist. If you apply regulations that are designed to favour one contestant, it's not longer a fair comparison.
  - rented_mule 3y ago
    I walked to work for over a decade before I retired. I stopped at all the red lights and beat the cars most days. Bikes and pedestrians can go much faster than cars between lights when traffic is bad enough. Sure, there is favorable treatment (pedestrians get their own "roads" and bikes can drive between lanes), but there is no similar treatment that would make sense for cars because they are too big and insufficiently nimble.
  - ornornor 3y ago
    If anything, bicycles are very rarely (in some places, never) favoured over cars in urban planning/design.
- m463 3y ago
  300kw is peak power. I think teslas are pretty efficient: https://forum.abetterrouteplanner.com/blogs/entry/22-tesla-model-3-performance-vs-rwd-consumption-real-driving-data-from-233-cars/ https://forum.abetterrouteplanner.com/blogs/entry/22-tesla-m... A model 3 LR uses less than 100 watt hours to go 1 mile at 25mph I wonder how efficient bikes become at higher speeds with respect to drag coefficient (without a streamlined fairing)
contravariant 3y ago
> On the other hand, pedaling a bicycle, or pushing a car is a lot of work. One of these is not like the other. Pedalling a bike doesn't come even close. Humans consume several million calories per day at most, now as a rule of thumb a million calories is about the same as a kWh. And the only reason they consume that much energy is because the human body is inefficient at converting this heat to work. Even the best cyclists struggle to produce anything more than a few hundred watt. More to the point, humans struggle to power a light bulb, let alone a house.
- Wicher 3y ago
  > And the only reason they consume that much energy is because the human body is inefficient at converting this heat to work. The human body does not convert heat to work. We do something entirely different (look up the "ATP/ADP cycle"). But yeah there are certainly conversion losses in the conversion of egg sandwiches to labor. 25% or so. Which is actually pretty good; you won't be able to match that with a steam machine built over the weekend (start with solving the problem of setting eggs on fire?).