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Digestion-carbohydrate-ATP-energy efficiency

  1. May 22, 2008 #1
    how efficiently do we turn our food into energy?

    I have been kind of wondering if in the future it might be possible, and, a good idea to use biological processes to make energy out of food for energy? I know we can already process plants and extract sugar to make ethinol, or oil for biodiesel, but how efficient is this compared to say a cow eating the plant.

    I can just picture a sci fi movie where vehicles have cow stomaches and other parts hooked up to electric motors and you just add grass or maybe even sticks and stuff.
  2. jcsd
  3. May 26, 2008 #2
    Not very.
    When secondary and tertiary consumers consumes, energy is lost within the system.
    That explains why food webs at most only goes on up to 4 to 5 levels with humans at the top. So cows which consumes plant, would have less energy than the plant, since it is a larger organism and would need more energy to sustain it's life through respiratory and other metabolic activities.
    It is also not very stable for our economy since it would mean a more competitive market for energy and it use as a source of food. We can see this in the recent rise in gas prices and food prices as well as the recession within the economy. In addition, it is also not very effective. Take ethanol for example. Statistic have been done and shown that if every family in the world has yield a field of corn it still would not be enough to satisfy the demand for ethanol. Furthermore, ethanol actually hurts the ecosystem more than oil. The major fear of oil is that it releases carbon monoxide, the stuff that comes from the exhaust of our cars. However, ethanol, when burn, actually releases more carbon than oil.
  4. May 26, 2008 #3
    But wouldn't the carbon release from ethanol be carbon neutral, considering more crops would be planted to consume the increased CO2 level in proportion to use?
  5. May 26, 2008 #4
    Considering All flow of carbon in has ceased. But since many people are gonna continue their use of oil the flow will continue but not as of a high rate as before. In addition, crops takes time. In the amount of time and space given, the crops would only act as a medium to contain the carbon for a short period of time before it would be release again.

    More carbon> same crop= epic fail.

    Cause I hardly don't many consumer product will rely on ethanol to power it. If we want to seriously capture carbon, we need to plant more trees, which would be a better, more "permanent" method, since trees use carbon as a building block, but for Tr345, the future of energy should be found in water, not in food sources.
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