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It's clear that different fuels can have a different carbon impact. A "C atom from a biofuel" may in isolation be indistinguishable from one sourced from a foss

It's clear that different fuels can have a different carbon impact. A "C atom from a biofuel" may in isolation be indistinguishable from one sourced from a fossil fuel, but it is exactly not the same in terms of its impact; claiming so is obviously disingenuous. None of this means that biofuels are actually an effective method to reduce the carbon impact of aviation. Life-cycle analysis is pretty hard. We can broadly say that most biofuels are carbon neutral in the gross sense, but the carbon cost of their production could mean that they have an equivalent or even greater overall carbon impact than fossil fuels. It requires energy to transport and process biomass, and changes in land use can have second-order effects – like impacts on food production. It is, in fact, pretty darned complicated. Reducing this to "everyone except me is an idiot sucker" is not even slightly helpful.

WalterBright 3y ago
> A "C atom from a biofuel" may in isolation be indistinguishable from one sourced from a fossil fuel, but it is exactly not the same in terms of its impact How does it result in less CO2 in the atmosphere?
- jamiek88 3y ago
  Because the fuel is grown and used instead of refined fuel from ancient oil. Carbon neutral. Standard fuel: I dig up one carbon. I burn this carbon. One carbon is now in atmosphere. Biofuel: I grow one carbon. one carbon is now taken from the atmosphere. We are at minus one carbon. I burn this carbon. We are back to net zero carbon taken or added.
  - WalterBright 3y ago
    Every reply to me makes the same mistake. The fix: Grow a tree. Burn a tree you dug up. Net zero carbon.
    - progman32 3y ago
      Until that tree that was just planted dies and decays back into co2. I understand that there's ways to prevent this from happening for a while, but I'm not convinced that the economics of that work well enough to offset the high quantity demand of aviation fuel. We already grow lots of trees to use in houses etc. In any case, your comments helped me understand the greater picture. I still think biofuels are a good idea for the near future. They may be an economic hack, but I think they'll work. We likely disagree on this.
      - WalterBright 3y ago
        > Until that tree that was just planted dies and decays back into co2. Unless you build a house with the wood. Wood is a great building material. Unlike concrete, which releases CO2 in its production, wood construction reduces CO2. Besides, you'll never ever create enough biomass to fuel the economy, and you'll wreck the environment trying.

WalterBright 3y ago

> A "C atom from a biofuel" may in isolation be indistinguishable from one sourced from a fossil fuel, but it is exactly not the same in terms of its impact How does it result in less CO2 in the atmosphere?

jamiek88 3y ago
Because the fuel is grown and used instead of refined fuel from ancient oil. Carbon neutral. Standard fuel: I dig up one carbon. I burn this carbon. One carbon is now in atmosphere. Biofuel: I grow one carbon. one carbon is now taken from the atmosphere. We are at minus one carbon. I burn this carbon. We are back to net zero carbon taken or added.
- WalterBright 3y ago
  Every reply to me makes the same mistake. The fix: Grow a tree. Burn a tree you dug up. Net zero carbon.
  - progman32 3y ago
    Until that tree that was just planted dies and decays back into co2. I understand that there's ways to prevent this from happening for a while, but I'm not convinced that the economics of that work well enough to offset the high quantity demand of aviation fuel. We already grow lots of trees to use in houses etc. In any case, your comments helped me understand the greater picture. I still think biofuels are a good idea for the near future. They may be an economic hack, but I think they'll work. We likely disagree on this.
    - WalterBright 3y ago
      > Until that tree that was just planted dies and decays back into co2. Unless you build a house with the wood. Wood is a great building material. Unlike concrete, which releases CO2 in its production, wood construction reduces CO2. Besides, you'll never ever create enough biomass to fuel the economy, and you'll wreck the environment trying.