Energy to Move


Here's some neat stuff from Wikipedia. The fuel efficiency of everything can be compared in terms of passenger seat miles: how much gas to move one passenger (the seat) for one mile. On wikipedia, they reduced it to mega-Joules and kilometers, but you can put it all together. So here you go, in order from best to worst (with some surprises in there...) are all the energy quantities burned, to move you one kilometer

  • heavy rail (long haul freight, flat ground, no stopping) 0.5 ml Wow!
  • Ocean liner: 1.7ml
  • bicycle, 4mL Nothing biological can touch a human on a bike.
  • walking, 10mL Still good, but not close to a bike.
  • regenerating diesel-bus 10mL (but only if it's full of people)
  • supercar: 20ml (next gen VW tandem diesel, @ 870mpg with 2 pax)
  • Jetliner (no kidding!) 30ml
  • hybrid (prius) 40ml
  • luxury ocean liner, 170ml
Couple of caveats, the speed really, really matters! Cars lose half their thrust to drag (and airplanes lose ALL their thrust to drag). What that means is that that VW supercar could probably beat a bike, running at similar speeds, but you're not likely to use it that way. Another thing you're not likely to use full is a diesel bus, which gets 5-6 MPG if it doesn't stop too much, so that thing is an environmental disaster if it's not at least half full. That's why we have to subsidize busses: they don't make sense.

Wikipedia declined to discuss pure electric or hydrogen cars because they are hard to compare: there are sequences of losses in the generation, distribution, charge and discharge of the electricity, (or Hydrogen) and it's all powered by the worst fuel known (coal. Hydrogen and electricity are not energy sources, they're converted coal (or nuclear) energy) but on a basis of raw cost to you, it's pretty cheap. I'll try to figure it out and post it, converting coal to gas on the basis of $, and on the basis of energy (which will be two dramatically different numbers).

Finally, the shot glass? That's 30ml, enough to move you one kilometer at Mach .6. Only it's drambuie, not Jet-a, so I drank it.

No comments:

Post a Comment