Ah, sorry. I thought it was interesting to compare the efficiency/energy consumption of different methods of transport, because these (at least for me) didn't completely line up with my intuition.
Ah, sorry. I thought it was interesting to compare the efficiency/energy consumption of different methods of transport, because these (at least for me) didn't completely line up with my intuition.
Worse, the reference used for that number is a dead link. It also depends on a country-by-country basis as train usage in the US is different than that of e.g. The Netherlands. For the latter, an...
Exemplary
Worse, the reference used for that number is a dead link.
It also depends on a country-by-country basis as train usage in the US is different than that of e.g. The Netherlands.
For the latter, an older study (1997) I could find yields roughly an average of 100 J per km per passenger for trains. That is 5 times better than a Tesla 3. And I can only presume that in the last 25 years, trains have become even more efficient.
Additionally, Tesla's fuel economy does not include the use of airco or heating, while these numbers are included in the above study for trains.
They're even better in terms of the cost of that energy compared to human propulsion. Terms and conditions apply, see also some of the explanations below the table. But basically, the efficiencies...
They're even better in terms of the cost of that energy compared to human propulsion. Terms and conditions apply, see also some of the explanations below the table. But basically, the efficiencies of the whole pipeline from grid electricity to kinetic energy are quite high for an electric bike. Meanwhile, the same energy use in the bike via human power is much less efficient. Food is just not a great fuel in terms of kJ/$, because it's quite difficult to produce. (I'm just going to use dollars as an approximation of true costs and effort. Feel free to do the math a different way.)
To illustrate that: A human's daily caloric needs amount to roughly 100W of power. If you could run your body off of electricity, that would cost you 140$ per year. Instead, most people will probably consume as much food in a month or less. That's how much more expensive human power is compared to electric power: 12x or more. This is reflected in a much higher CO2 cost of food relative to other forms of energy, but that's harder to quantify than the dollar amounts.
I'm not saying "don't move, it's too costly". This is purely in an energy efficiency context. Movement is good, we should almost all do more of it.
I mean, if you decide you want to maximize calories per dollar spent and you replace 100% of your diet with canola oil, you're looking at something like $300 for a year's worth of calories. Food...
I mean, if you decide you want to maximize calories per dollar spent and you replace 100% of your diet with canola oil, you're looking at something like $300 for a year's worth of calories.
Food isn't expensive in USD/J terms because it's an inefficient source of energy; it's expensive in those terms because it does a lot of other stuff, including providing essential non-caloric nutrition and recreation.
I'm skeptical of the ebike efficiency vs regular bike. Pedal powered bikes are typically much lighter and more aerodynamic than ebikes. In any case, I don't see any chance for ebikes to be over...
I'm skeptical of the ebike efficiency vs regular bike. Pedal powered bikes are typically much lighter and more aerodynamic than ebikes. In any case, I don't see any chance for ebikes to be over twice as efficient.
One possible explanation might be the energy used in making food, but that sort of thing doesn't seem to be addressed on this page and the sources for the ebike efficiency seem to be looking at straight aerodynamics and power at the battery/motor and not where the energy comes from. Also, source 15 for the pedal bicycle is for running vs walking? 23 is gasoline vs metabolic calories. No idea what's happening there.
I didn't look deeply into this, but I suspect an error. I suspect ebikes and pedal bikes should be almost the same in terms of efficiency at the drivetrain, with pedal bikes winning out slightly on average (nice road bikes pushing the average up). Ebikes may be better if we get into food production vs electricity production, but again that doesn't seem to be what's happening on this table.
Main efficiency killer for peadal bikes is that we loose a ton of efficiency in converting food calories to mechanical energy, and while the peadal mechanism is pretty good at converting linear...
Main efficiency killer for peadal bikes is that we loose a ton of efficiency in converting food calories to mechanical energy, and while the peadal mechanism is pretty good at converting linear mucsle power to rotation, its not going to compare to the 90+% efficiency of an electric motor and battery.
Note that bare links to Wikipedia without any context are generally discouraged.
Is there something about this article/section you wanted to discuss?
Ah, sorry. I thought it was interesting to compare the efficiency/energy consumption of different methods of transport, because these (at least for me) didn't completely line up with my intuition.
Could you point to specific examples that seem unintuitive?
I would never have thought a Tesla Model 3 would be competitive with a commuter train.
I'm suspicious of that number since they don't include the load factor they assume for rail.
Worse, the reference used for that number is a dead link.
It also depends on a country-by-country basis as train usage in the US is different than that of e.g. The Netherlands.
For the latter, an older study (1997) I could find yields roughly an average of 100 J per km per passenger for trains. That is 5 times better than a Tesla 3. And I can only presume that in the last 25 years, trains have become even more efficient.
Additionally, Tesla's fuel economy does not include the use of airco or heating, while these numbers are included in the above study for trains.
Toyota Prius was lower than I expected compared to the Teslas.
I had no idea e-bikes were so efficient, I wish I had more useful places to go with mine other than just zooming around the neighborhood
They're even better in terms of the cost of that energy compared to human propulsion. Terms and conditions apply, see also some of the explanations below the table. But basically, the efficiencies of the whole pipeline from grid electricity to kinetic energy are quite high for an electric bike. Meanwhile, the same energy use in the bike via human power is much less efficient. Food is just not a great fuel in terms of kJ/$, because it's quite difficult to produce. (I'm just going to use dollars as an approximation of true costs and effort. Feel free to do the math a different way.)
To illustrate that: A human's daily caloric needs amount to roughly 100W of power. If you could run your body off of electricity, that would cost you 140$ per year. Instead, most people will probably consume as much food in a month or less. That's how much more expensive human power is compared to electric power: 12x or more. This is reflected in a much higher CO2 cost of food relative to other forms of energy, but that's harder to quantify than the dollar amounts.
I'm not saying "don't move, it's too costly". This is purely in an energy efficiency context. Movement is good, we should almost all do more of it.
I mean, if you decide you want to maximize calories per dollar spent and you replace 100% of your diet with canola oil, you're looking at something like $300 for a year's worth of calories.
Food isn't expensive in USD/J terms because it's an inefficient source of energy; it's expensive in those terms because it does a lot of other stuff, including providing essential non-caloric nutrition and recreation.
The Queen Mary only goes 50 feet on a gallon of fuel. But PER passenger it works out to about 14 mpg. Not as terrible as you'd think.
I'm skeptical of the ebike efficiency vs regular bike. Pedal powered bikes are typically much lighter and more aerodynamic than ebikes. In any case, I don't see any chance for ebikes to be over twice as efficient.
One possible explanation might be the energy used in making food, but that sort of thing doesn't seem to be addressed on this page and the sources for the ebike efficiency seem to be looking at straight aerodynamics and power at the battery/motor and not where the energy comes from. Also, source 15 for the pedal bicycle is for running vs walking? 23 is gasoline vs metabolic calories. No idea what's happening there.
I didn't look deeply into this, but I suspect an error. I suspect ebikes and pedal bikes should be almost the same in terms of efficiency at the drivetrain, with pedal bikes winning out slightly on average (nice road bikes pushing the average up). Ebikes may be better if we get into food production vs electricity production, but again that doesn't seem to be what's happening on this table.
Main efficiency killer for peadal bikes is that we loose a ton of efficiency in converting food calories to mechanical energy, and while the peadal mechanism is pretty good at converting linear mucsle power to rotation, its not going to compare to the 90+% efficiency of an electric motor and battery.