LogFAQs > #972611163

SinisterSlay posted...

Pedal powered would be the least sustainable version.

Do you know what the most inefficient source of power is?
You.
Do you realize how much you would have to eat (ok fine we already eat to much, but it would increase) just to be strong enough to pedal your family around like that?

You might be surprised how little energy it takes. If memory serves, a ~200 lb person cycling at 25 mph/40 km/h burns around 50 active calories per mile (30 per km), which isn't actually that much. Getting to the point of being fit enough to haul around double or triple that would take a considerable amount of work, certainly, but it's far from implausible, especially when you start considering options like tandems or shadow bikes that let the passengers provide some extra power (often with considerably less added weight than would be involved if they had a bike of their own). By comparison, gasoline holds about 31,000 calories per gallon, which at 50 mpg works out to 620 calories per mile.

More than the efficiency of the system/fuel, the efficiency of pedal power comes from how much lighter the vehicle can be. The vast majority of ICE cars weigh upwards of 1500 pounds, as a simple function of the weight of the engine, the weight of the materials needed to support that, and the weight of the materials needed to prevent occupants from being killed by another vehicle of a similar weight. Electric cars often weigh even more, since batteries are inherently heavy, and that problem is made even worse by trying to design EV's like regular cars (especially with how "regular cars" is increasingly meaning "oversized SUVs and vanity pickup trucks"). The mechanism needed for pedal propulsion, however, is incredibly limited and lightweight, such that most bikes are well under 50 pounds. That simply means less energy required to move them.