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Is that a bicycle pedaled by a human, i.e., who converts calories into work at about 25% efficiency? Does it take into account the farming and supply chain cos

Is that a bicycle pedaled by a human, i.e., who converts calories into work at about 25% efficiency? Does it take into account the farming and supply chain costs of that food it's about 15% efficiency by calorie, compared with gasoline which is close to 90% efficient IIRC. Or is it just food/fuel energy -> work?

occz 4y ago
You can dig into the numbers on this helpful article: https://en.wikipedia.org/wiki/Energy_efficiency_in_transport https://en.wikipedia.org/wiki/Energy_efficiency_in_transport
- karthikb 4y ago
  That article explicitly states that it doesn’t account for the energy or emissions required to produce the fuel. The lifecycle emissions of an EV depend on how the electricity was generated, and the total emissions of cycling depends on the diet of the cyclist - even though the energy per distance is the same regardless.
hot_gril 4y ago
Gasoline isn't 90% efficient. But yes, there's a study showing that a bicyclist with a meat-heavy diet is overall contributing more CO2 per mile than a modern ICE car. Electric bike is way more efficient.
- ZeroGravitas 4y ago
  This reminds me of the classic "if you wash recycling with water heated with electricity generated with coal it's not very carbon efficient". Yes, that might be true, but it's the "coal" that's the issue, not the recycling. It says so little useful about recycling that it's basically a lie. But it does suggest we should phase out coal, not just to make recycling cleaner, but for everyone that uses electricity. Similarly, I assume this study looked at red-meat reared in a GHG callous manner. Which says basically nothing about bicycles, but does tell us that we should take the obvious steps we're already aware of to decarbonize food. Not because it helps cyclists be more efficient, but because it's a smart thing to do for everyone who eats. > Indeed, the use of fertilizers, methane gas released from livestock like cattle and massive food waste all contribute to the vast carbon footprint of food production. Since land is both a source and a sink of CO2, land-clearing for new agricultural terrain in tandem with deforestation drives harmful emissions, equating to approximately 26% of the global total.
- Xylakant 4y ago
  I’d love to see that study and see if it takes into account how much energy was expended constructing the car vs the bike and the roadway required for the car. CO2/Mile on a basis of marginal energy invested for each extra mile is not a valid comparison.
  - hot_gril 4y ago
    https://keith.seas.harvard.edu/blog/climate-impacts-biking-vs-driving https://keith.seas.harvard.edu/blog/climate-impacts-biking-v... It doesn't count the manufacturing of each. It's still a valid comparison without it, cause most Americans who have a bike probably also have a car that they need for trips that aren't bike-able, and also cause it helps to separate fixed and marginal costs anyway.
    - Xylakant 4y ago
      There are other places I. The world where this is not true. For example, more than 50% of all households within this S-Bahn ring in Berlin (let’s call that the extended center) do not own a car. The bike may also replace a second or third car. Not counting the cost of manufacture is just sloppy. They also picked a car that is twice as efficient as the average car for comparison and the most meat-heavy fiery possible (essentially meat only). That’s interesting as a though experiment, but not as a basis for policy- which is exactly what they state in their preface.
      - hot_gril 4y ago
        Yeah, it's not for policy, otherwise it'd have to target a particular jurisdiction too. It's for individual interpretation. If you eat a lot of meat and own a car and a bike already, maybe think about biking more as a healthy exercise than a way to help the environment, or think of meat as a bigger problem for it.
  - LunaSea 4y ago
    The roadway is also required for bikes.
- 7952 4y ago
  This only really matters if cyclists eat more than motorists. And you might as well include other lifestyle factors at the same time.
- throwawaylinux 4y ago
  Well I'm not sure. Refining is over 90% and so is extraction by the looks, but combined and add transport and yeah maybe it's more like 80%, in any case it's around an order of magnitude more efficient than western food production isn't it?
arghwhat 4y ago
> gasoline which is close to 90% efficient IIRC. Common gasoline engines have an efficiency around 30-40%, assuming modern high-efficiency designs. For older designs this is closer to 20%.
- throwawaylinux 4y ago
  I'm talking about the production of gasoline there (vs production of food).
  - arghwhat 4y ago
    Ah, my mistake. Your number matches gasoline refinement (I see 85% quoted), but that's only one part of the gasoline supply chain.

occz 4y ago

You can dig into the numbers on this helpful article: https://en.wikipedia.org/wiki/Energy_efficiency_in_transport https://en.wikipedia.org/wiki/Energy_efficiency_in_transport

karthikb 4y ago
That article explicitly states that it doesn’t account for the energy or emissions required to produce the fuel. The lifecycle emissions of an EV depend on how the electricity was generated, and the total emissions of cycling depends on the diet of the cyclist - even though the energy per distance is the same regardless.

hot_gril 4y ago

Gasoline isn't 90% efficient. But yes, there's a study showing that a bicyclist with a meat-heavy diet is overall contributing more CO2 per mile than a modern ICE car. Electric bike is way more efficient.

ZeroGravitas 4y ago
This reminds me of the classic "if you wash recycling with water heated with electricity generated with coal it's not very carbon efficient". Yes, that might be true, but it's the "coal" that's the issue, not the recycling. It says so little useful about recycling that it's basically a lie. But it does suggest we should phase out coal, not just to make recycling cleaner, but for everyone that uses electricity. Similarly, I assume this study looked at red-meat reared in a GHG callous manner. Which says basically nothing about bicycles, but does tell us that we should take the obvious steps we're already aware of to decarbonize food. Not because it helps cyclists be more efficient, but because it's a smart thing to do for everyone who eats. > Indeed, the use of fertilizers, methane gas released from livestock like cattle and massive food waste all contribute to the vast carbon footprint of food production. Since land is both a source and a sink of CO2, land-clearing for new agricultural terrain in tandem with deforestation drives harmful emissions, equating to approximately 26% of the global total.
Xylakant 4y ago
I’d love to see that study and see if it takes into account how much energy was expended constructing the car vs the bike and the roadway required for the car. CO2/Mile on a basis of marginal energy invested for each extra mile is not a valid comparison.
- hot_gril 4y ago
  https://keith.seas.harvard.edu/blog/climate-impacts-biking-vs-driving https://keith.seas.harvard.edu/blog/climate-impacts-biking-v... It doesn't count the manufacturing of each. It's still a valid comparison without it, cause most Americans who have a bike probably also have a car that they need for trips that aren't bike-able, and also cause it helps to separate fixed and marginal costs anyway.
  - Xylakant 4y ago
    There are other places I. The world where this is not true. For example, more than 50% of all households within this S-Bahn ring in Berlin (let’s call that the extended center) do not own a car. The bike may also replace a second or third car. Not counting the cost of manufacture is just sloppy. They also picked a car that is twice as efficient as the average car for comparison and the most meat-heavy fiery possible (essentially meat only). That’s interesting as a though experiment, but not as a basis for policy- which is exactly what they state in their preface.
    - hot_gril 4y ago
      Yeah, it's not for policy, otherwise it'd have to target a particular jurisdiction too. It's for individual interpretation. If you eat a lot of meat and own a car and a bike already, maybe think about biking more as a healthy exercise than a way to help the environment, or think of meat as a bigger problem for it.
- LunaSea 4y ago
  The roadway is also required for bikes.
7952 4y ago
This only really matters if cyclists eat more than motorists. And you might as well include other lifestyle factors at the same time.
throwawaylinux 4y ago
Well I'm not sure. Refining is over 90% and so is extraction by the looks, but combined and add transport and yeah maybe it's more like 80%, in any case it's around an order of magnitude more efficient than western food production isn't it?

arghwhat 4y ago

> gasoline which is close to 90% efficient IIRC. Common gasoline engines have an efficiency around 30-40%, assuming modern high-efficiency designs. For older designs this is closer to 20%.

throwawaylinux 4y ago
I'm talking about the production of gasoline there (vs production of food).
- arghwhat 4y ago
  Ah, my mistake. Your number matches gasoline refinement (I see 85% quoted), but that's only one part of the gasoline supply chain.