Ethanol From Waste Straw

>>>"NREL's research showed that one quad (ten billion gallons) of
>
> biodiesel
>
>>>could be produced from 200,000 hectares of desert land
>
> Err, this is nonsense.
>
> You can grow precisely nothing on desert land, that is why it is
> called "desert".
>
> To convert desert land into arable land is a massive undertaking,
> involving major infrastructure investments, e.g. irrigation and
> transportation.
>

You're probably right as far as the scale. I assume the plan would
involve using salt water algae, with the water coming from the sea and
possibly returning to it -- and likely as not, such a project would face
big and controversial environmental impact statement debates! (Deserts
actually can have rich ecosystems of their own type -- lots of lizards,
burrowing insects, cactus, turtles, etc.).

> The cost of this project would be comparable to the cost of
> building a constellation of solar power satellites.

Again, you're probably right. However, creating algae ponds in the
desert using lots of concrete or whatever you is fairly low risk
technically compared to creating space settlements and then SSPS in the
sense that people have been building irrigation canals and ponds and
moving water around for centuries. So even though people who frequent
this newsgroup might be convinced the space option is better for a lot
of reasons and low risk in many senses, when it comes down to
convincing, say, pension fund managers etc. to put up money for
projects, I would think the desert ethanol farmers will have an easier
time getting funding -- especially since the work can proceed
incrementally, building one pond and then moving on to the next - versus
building Island One, a lunar mass driver, space manufacturng systems
etc. and then finally building a first SPS. An incremental project based
on widely know engineerign techniques is almost always going to seem
less risky than one which has a lot of new prerequisites that have to be
built first in remote locations with high operating costs. Now oviously,
if the SPS units were launched from Earth using advanced PV, then the
project might actually be lower risk -- but then it is more expensive
and loses any possible benefits of space based manufacturing regarding
pollution etc. Yet, it would seem as a proof of concept, people may
never support a big SSPS initiative involving space settlemtn, mass
drivers, etc. unless at least one SPS has been launched from Earth and
used to power a factory or whatever for some time (even if
uneconomically) -- just to prove that part of the concept. (Yes, I'll
acknowledge it'll probably work -- but IMHO smart money would want to
see it done once anyway.)

--Paul Fernhout