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There are no carbon neutral fuels 'with' agriculture. Afaik, no bio-fuel scheme, including ethanol from sugar cane in Brazil, is carbon negative. I might be wr

There are no carbon neutral fuels 'with' agriculture. Afaik, no bio-fuel scheme, including ethanol from sugar cane in Brazil, is carbon negative. I might be wrong or out of date, but my last dive into this resulted in an understanding that we'd be better off just using turning the carbons required to grow the things we would eventually turn back into energy and using it. Agriculture as it currently stands globally is a carbon source from an LCA perspective, and that includes biofuels.

marcosdumay 4y ago
A bio-fuel can not be carbon negative, by definition. At most it can be neutral. And yes, none is neutral either. > my last dive into this resulted in an understanding that we'd be better off just using turning the carbons required to grow the things But this is a huge jump, without subsidizing evidence, and known to be false. Just because the fuel emits carbon, it doesn't mean it emits as much carbon as natural gas. Only corn ethanol fails at this and emits more than the original fuel.
- RosanaAnaDana 4y ago
  Well we dont use natural gas to move things around I suppose is the point. My last foray into this was almost a decade ago, but when I did the work, I know that the physical movement of things (in the case I was working on it was jet fuel from oilseeds) was a very significant factor in the overall analysis. The moving of thing A from location X to location Y to convert it into product B, then to move product B to location Z to convert into product C ended up being more than enough to flip the whole thing over. I think the next biggest factor was the grid mix for the conversion steps. I think another conclusion was that if we could do it all on-site, it did pan out. If farmers could use marginal land, didn't have to move the seed offsite, and had the additional equipment to convert from oil -> bio-diesel, it might make sense for some growers. All of that understanding may well be obsolete now. TLDR: Moving heavy stuff around burns a lot of fuel. If you have to move things from place to place, its just not worth it.

marcosdumay 4y ago

A bio-fuel can not be carbon negative, by definition. At most it can be neutral. And yes, none is neutral either. > my last dive into this resulted in an understanding that we'd be better off just using turning the carbons required to grow the things But this is a huge jump, without subsidizing evidence, and known to be false. Just because the fuel emits carbon, it doesn't mean it emits as much carbon as natural gas. Only corn ethanol fails at this and emits more than the original fuel.

RosanaAnaDana 4y ago
Well we dont use natural gas to move things around I suppose is the point. My last foray into this was almost a decade ago, but when I did the work, I know that the physical movement of things (in the case I was working on it was jet fuel from oilseeds) was a very significant factor in the overall analysis. The moving of thing A from location X to location Y to convert it into product B, then to move product B to location Z to convert into product C ended up being more than enough to flip the whole thing over. I think the next biggest factor was the grid mix for the conversion steps. I think another conclusion was that if we could do it all on-site, it did pan out. If farmers could use marginal land, didn't have to move the seed offsite, and had the additional equipment to convert from oil -> bio-diesel, it might make sense for some growers. All of that understanding may well be obsolete now. TLDR: Moving heavy stuff around burns a lot of fuel. If you have to move things from place to place, its just not worth it.