Interesting comment that inspired me to look into the grams of carbon dioxide emitted when running biodiesel fuel:
This page [1] says biodiesel emits 2,661 grams of carbon dioxide per gallon. Let’s say a 1988 F250 gets 15 mpg => 2,661 g/gal * 1/15 gal/mile = 177.4 gram CO2/mile.
Pretty cool it’s less than both the Chevy Malibu and Hummer but wonder how it compares to other petrol cars - it is just proportional to fuel economy but im not gonna run the numbers. In my head a pure gasser car would need to get above about 40mpg of petroleum fuel to emit less grams of CO2 than a 15mpg vehicle running pure biodiesel.
TLDR biodiesel is what’s up if you can’t afford an ev (and still has its place if you can).
Pure petroleum diesel still barely emits more co2 than gasoline anyway [2]
Disclaimer: only comparing carbon dioxide and not other greenhouse gas emissions
Edit: i'm seeing some numbers around that the average human exhalation per day is emits 1 kg of CO2, for reference. [3]
The thing with human exhalation is that this CO2 comes from the food we consume and gets captured again when food is produced thus having netzero influence on the actual CO2 in the atmosphere. Same basically applies to biodiesel. Of course that ignores energy spent to produce crops and other issues like fertilizer.
The problem is the fossil fuel that is concentrated carbon from millions of years of plants and now just adds to the CO2 in the atmosphere without a corresponding mechanism to take it out again.
If we create gasoline by capturing CO2 from the atmosphere there isn't a CO2 problem with using it for fuel. Processes exist, but all have some (major) inefficiency issues.
Biodiesel is interesting but if you end up using palm nuts as the oil source and the producers are clear cutting forests to plan palms then the climate story gets muddy.
Indeed, although palm nuts/oil as the result of clear-cutting is a straw man. I do agree, however, biodiesel is quite a varied product. There could be biodiesel made from palm or beef/meat byproducts (tallow), which could in theory come from a clear-cut area.
But it would likely constitute a very small volume of biodiesel (compared to soy for example [1]).
Soy ain’t perfect either (gmo, mono cropping etc etc) but certainly better than petroleum.
Edit/Note: I’m in the US and typically seek out data for the North American region. Maybe palm oil biodiesel is a bigger thing in other parts of the world (Africa, Europe, Asia?) - not sure. Would be intrigued if there is data supporting it either way. The US dataset below has “no data” explicitly stated for palm oils.
This page [1] says biodiesel emits 2,661 grams of carbon dioxide per gallon. Let’s say a 1988 F250 gets 15 mpg => 2,661 g/gal * 1/15 gal/mile = 177.4 gram CO2/mile.
Pretty cool it’s less than both the Chevy Malibu and Hummer but wonder how it compares to other petrol cars - it is just proportional to fuel economy but im not gonna run the numbers. In my head a pure gasser car would need to get above about 40mpg of petroleum fuel to emit less grams of CO2 than a 15mpg vehicle running pure biodiesel.
TLDR biodiesel is what’s up if you can’t afford an ev (and still has its place if you can). Pure petroleum diesel still barely emits more co2 than gasoline anyway [2]
Disclaimer: only comparing carbon dioxide and not other greenhouse gas emissions
Edit: i'm seeing some numbers around that the average human exhalation per day is emits 1 kg of CO2, for reference. [3]
[1]: https://impactful.ninja/the-carbon-footprint-of-biodiesel/
[2]: https://theicct.org/sites/default/files/Gas%20_v%20_Diesel_%...
[3]: https://www.sciencefocus.com/planet-earth/how-much-does-huma...