[permaculture] Re: Biodiesel (Not Biogas)

Toby Hemenway hemenway at jeffnet.org
Thu Mar 7 12:16:55 EST 2002

on 3/6/02 4:02 PM, storm at emstorm at sonic.net wrote:

> but I have a few
> questions about plant based substitutes for petroluem based fuels.

Eric has raised some good points. I'm all in favor of using waste and
by-products for fuel, such as fryer oil for biodiesel. But a simple
back-of-the-envelope calculation of how much farmland it would take to
substitute biofuels for even a modest fraction of fossil fuel shows that the
only answer is to drastically reduce consumption. Here's a thought
experiment: look at your car's fuel tank, think about how many times you
fill it per year and what volume of fuel that is. Then imagine how many
acres of, say, oilseed sunflowers you would need to grow each year to
provide that volume of refined oil for your own car. Then multiply by a few
hundred million cars.

I've forgotten where I read it, but to provide biofuel for America's cars
would mean using 3-5 times more farmland than is now used for all crops--all
in monoculture, fertilized, mechanically harvested, etc. etc. An absurd and
depressing notion.


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