> However, regarding hemp qua fuel: inasmuch as hemp still has to be cultivated,
> there's an energy cost associated with that. Assuming hemp is as efficient as
> soybeans at generating oil (that seems like a conservative estimate), and
> assuming similar cultivation/processing costs (not sure this is true), a first
> approximation of the energy credit (or debt) ought to be easily calculable. I
> don't have the numbers at present. But we don't see a lot of soybean-powered
> cars, do we? Now if hemp were incredibly better as a fuel, or incredibly cheaper
> to cultivate, this use might still pan out. I'm curious to know if the book you
> mention goes into this, or just handwaves about it.
I don't have the numbers either, but I know that from all
appearances, hemp is pretty easy and cheap to grow if you don't have
to hide it from the police.
But fundamentally, hemp -- or soybean -- oil as a substitute for
gasoline, isn't going to happen for a while because they are
solutions to a non-problem. Solutions that have to compete against
an existing infrastructure which has no apparent need to accommodate
them, and without the ability to provide any apparent advantages.
Now, it is a given that eventually we will run out of fossil fuels.
When the supply actually runs low enough to drive the cost of
fossil-fuel-derived gasoline high enough, something will be done.
Today, though, we are not at that point and we have no reason to
believe we're anywhere particularly close to it.
And unless someone in the meantime finds it worthwhile to put a major
effort into tuning external-combustion engines (what we should have
done in the first place), the "something" that will most likely be
done is finding a way to make gasoline from some other raw material.
Perhaps hemp oil or soybean oil.
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