3 ms·

Ok, yep that’s 100% BS. Burning food can produce more useful work in a heat engine than you get from humans doing labor so I’m baffled by what about this compa

by Retric 2y ago

Ok, yep that’s 100% BS. Burning food can produce more useful work in a heat engine than you get from humans doing labor so I’m baffled by what about this comparison seems to make sense to you. Ignoring that you’re still off by more than an order of magnitude. 100% of the energy content of oil can’t even be turned directly into work without losses. You get about 10% of its nominal energy content as useful work, less if you’re including energy costs of production, refining, and transport. Even if look at an oil well fire it’s incomplete combustion and not useful work.

_heimdall 2y ago
You're raising that humans eating food is lossy but then attempt to use the opposite to argue against me when it comes to efficiency in using energy from oil. That's pretty confusing and I'm not sure how it helps, I also am not sure why you are comparing burning food - we eat for much more than just the energy alone and the calorie (a measure of burning food) is a ridiculously stupid metric that assumes we run roughly like a steam engine.
- Retric 2y ago
  Nope, I’m saying you need to pick a consistent method. A) If you want move a plow, you can grow some oats/grass/whatever to feed some horses then use those horses, or using the same land for oats/wood/whatever and burn in an early tractor, or use oil. Nobody in 1900 was getting 20 people to pull a plow. All of those methods are turning some amount of chemical energy to produce useful work. As such looking into the chemical energy in food vs oil makes some sense though sunlight vs oil is a better comparison as tractors are burning a far more expensive product not crude oil. B) Alternatively, you can look at the amount of useful work from a barrel of oil after all losses and compare that to the work done by a horse or person after all losses. But again suddenly oil doesn’t look so hot. What you tried to do is compare the energy content of oil with some amount of useful work which is a silly comparison.

by Retric 2y ago

_heimdall 2y ago

You're raising that humans eating food is lossy but then attempt to use the opposite to argue against me when it comes to efficiency in using energy from oil. That's pretty confusing and I'm not sure how it helps, I also am not sure why you are comparing burning food - we eat for much more than just the energy alone and the calorie (a measure of burning food) is a ridiculously stupid metric that assumes we run roughly like a steam engine.

Retric 2y ago
Nope, I’m saying you need to pick a consistent method. A) If you want move a plow, you can grow some oats/grass/whatever to feed some horses then use those horses, or using the same land for oats/wood/whatever and burn in an early tractor, or use oil. Nobody in 1900 was getting 20 people to pull a plow. All of those methods are turning some amount of chemical energy to produce useful work. As such looking into the chemical energy in food vs oil makes some sense though sunlight vs oil is a better comparison as tractors are burning a far more expensive product not crude oil. B) Alternatively, you can look at the amount of useful work from a barrel of oil after all losses and compare that to the work done by a horse or person after all losses. But again suddenly oil doesn’t look so hot. What you tried to do is compare the energy content of oil with some amount of useful work which is a silly comparison.