What's wrong with this idea?

--- In spacesettlers@y..., "bobunf" wrote:
> Electricity produced from solar on Earth is much more expensive
than
> electricity produced from coal, nuclear, oil, gas, hydro or even
> wind. Producing electricity in space will cost more than
producing
> it on Earth. The principal advantage to space is that solar
> insolation is about three times what it would be at any point on
the
> Earth's surface.
>
> But the cost of delivering, assembling and maintaining electric
> generating equipment to and in orbit much exceed the cost of the
same
> tasks performed on Earth by orders of magnitude. But even if
> constructing this facility in orbit cost the same as on Earth (a
> ridiculous assumption within the range of any foreseeable
> technology), there would still be three show stoppers:
>
> 1. The losses inherent in converting electricity to some form of
> beamable energy which must be at least 50% and probably higher.

Why must it be? Is this new research that you're quoting? Could you
post a citation for us? The body of research that underlies the
discussion on this group has been performed by scientists, published
in peer-reviewed journals and their results have been duplicateable.
Unless you can provide us with some support for your claim that the
losses must be >50%, then I think I'll rely on the proven numbers
thus far, which show a conversion efficiency of 85% from DC to radio
frequency. In the SSI list, Charles Radley was able to provide some
data which was summerized by William Mook, that breaks the whole
process down as follows.

DC to RF 0.85. . . . . . .Conversion at the SPS
Antenna 0.98 . . . . . . .Power sent from SPS
Atmosphere 0.98. . . . . .Atmospheric attneuation
Energy Collection 0.88 . .Earth Rectenna Efficiency
RF to DC 0.89. . . . . . .Conversion at the Rectenna
Grid .97 . . . . . . . . .Convert DC to AC with Inverter

Thus, .85*.98*.98*.88*.89*.97 = 62.02% overall efficiency delivered
into the grid.

And
> there will additional losses in the energy beamaiming and
focussing
> will not be 100% perfect all the time, and there will be
atmospheric
> losses.
>
> 2. Converting this beamed energy back into electricity is not a
> trivial problem. The best technology for doing this currently
would
> be using a steam turbine generator at less than 40% efficiency.

How did you come up with the conclusion that a steam turbine
generator is the best option? You really should dig deeper into the
research on the matter of SPS and associated technologies!

>
> 3. The solar energy which is not converted into electricity will
be
> deposited as heat onto the power satellite. With photovoltic
there
> is a theoretical maximum efficiency of 37%. If there's not enough
> energy in the photon to flip the electron, all the energy of the
> photon is deposited as heat. If the photon carries excess energy,
> that excess is deposited as heat. The best commercially available
PV
> cells today opearate at less than 20% efficiency, and they are
very
> expensive.
>
> At least 63% of the solar energy must be deposited as heat,
probably
> closer to 80% with current off-the-shelf technology. In addition,
> the energy lost in converting electricity to beamable energy will
> also be deposited as heat. More than 80% of the energy received
from
> the sun will be used to heat the power satellite, and convention
is
> not available in a vacuum.
>
> Using current technology I calculate the electricity delivered
from a
> satellite would cost about 15,000 times more than today's
> conventionally supplied electricity. A $100 electric bill would
rise
> to $1.5 million.

Please show us how you calculate your 15,000X factor. I really want
to understand your argument, but all of your conclusions are
unsupported, so basically, I'm left with you presenting no argument
other than wild assertions.

If it comes down to having to compare your unsupported asertions
against those of others who have actually done published research
and show that SPS, less lift costs and space development costs, is
more than economically competitive against any earth based power
solution, then hands down I'll support those who actually present
evidence to supoort their conclusions.

And a last thought, do any of the earth based solutions have to
completely support the infrastructure they use on earth, e.g.
housing for workers, food they eat, transportation network,
vehicles, and development.