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At 10:10 PM 10/13/2007, you wrote:<br>
<blockquote type=cite class=cite cite="">"hkhenson"
<hkhenson@rogers.com><br>
> The microwave beam is only about 1/4 as intense as sunlight<br><br>
If you just wanted it to produce enough energy to just run the cars in
the<br>
USA the solar satellite in Geosynchronous orbit would look larger than
the<br>
full moon as seen on the Earth, and the receiving antenna would
cover<br>
several of the larger states in the western USA. Just doesn't sound
terribly<br>
practical to me.</blockquote><br>
Let's put numbers on it.<br><br>
<a href="http://en.wikipedia.org/wiki/Image:World_Energy_consumption.png" eudora="autourl">
http://en.wikipedia.org/wiki/Image:World_Energy_consumption.png</a><br>
<br>
World oil is about 5 TW, coal about 4 TW, gas about 3 and that covers 85%
of energy sources. Displacing coal and gas with SPS power is fairly
easy, making synthetic fuels from air and water is harder and probably
won't be terribly efficient.<br><br>
<a href="http://energy.cr.usgs.gov/energy/stats_ctry/Stat1.html" eudora="autourl">
http://energy.cr.usgs.gov/energy/stats_ctry/Stat1.html</a><br><br>
The US burns 40% of the world's oil, so that's about 2 TW. That's
2000GW, or 200 10 Gw power sats.<br><br>
<a href="http://en.wikipedia.org/wiki/Solar_power_satellite" eudora="autourl">
http://en.wikipedia.org/wiki/Solar_power_satellite<br><br>
</a>"For best efficiency, the
<a href="http://en.wikipedia.org/wiki/Satellite_antenna">satellite
antenna</a> should be
<a href="http://en.wikipedia.org/wiki/Circular">circular</a> and about 1
<a href="http://en.wikipedia.org/wiki/Kilometers">kilometers</a> in
<a href="http://en.wikipedia.org/wiki/Diameter">diameter</a> or larger;
the ground antenna
(<a href="http://en.wikipedia.org/wiki/Rectenna">rectenna</a>) should be
<a href="http://en.wikipedia.org/wiki/Elliptical">elliptical</a> and
around 14 kilometers by 10 kilometers. Smaller antennas would result in
increased losses to
<a href="http://en.wikipedia.org/wiki/Diffraction">diffraction</a>
/<a href="http://en.wikipedia.org/wiki/Sidelobe">sidelobes</a>. "For
the desired (23mW/cm²) microwave intensity
<a href="http://en.wikipedia.org/wiki/Solar_power_satellite#_note-intensity">
<sup>[31]</a></sup> these antennas could transfer between 5 and 10
<a href="http://en.wikipedia.org/wiki/Gigawatts">gigawatts</a> of power.
To be most cost effective, the system needs to operate at maximum
capacity. And, to collect and convert that much power, the satellite
would need between 50 and 100 square kilometers of collector area (if
standard ~14% efficient
<a href="http://en.wikipedia.org/wiki/Solar_cell#Comparison_of_energy_conversion_efficiencies">
monocrystalline silicon</a> solar cells were deployed)."<br><br>
Considering the rectennas to be 140 sq km each, 200 of them would occupy
28,000 sq km. Nevada is ten times this large. (286,367
km2)<br><br>
Since the rectennas would mostly be built over cropland. harvested
cropland is about 300 million acres or 1,214.056 sq km.
28,000/1,214,056 = 2.3% <br><br>
Now to replace all energy sources in the US would take about 3 times this
much, but we are still only talking about 30% of Nevada.<br><br>
<blockquote type=cite class=cite cite="">> Both fusion and fission
generate neutrons.<br><br>
Not all fusion reactions produce neutrons. The fusion reaction between
non<br>
radioactive deuterium (Hydrogen 2) and non radioactive Helium 3
produces<br>
non radioactive Helium 4, an easily controlled proton, 18.3 mev of
energy,<br>
and most important of all, no neutrons.<br><br>
Unfortunately you need a higher temperature to achieve it than the<br>
deuterium tritium reaction most are talking about. Also, there is not
much<br>
Helium 3 on the Earth, although there is probably a lot of it that could
be<br>
mined on comets and on the ice moons of the outer planets. Obviously
this<br>
is not exactly a short term solution; if regular fusion is always 30
years<br>
away then Helium 3 will happen 30 years after that.<br><br>
> neutrons can be silently diverted into making Pu 239.<br><br>
That is true, in fact you don't even need to do any secret diverting,
all<br>
nuclear power reactors produce Plutonium, it can't be prevented.
However<br>
as we've already made thousands of tons of the stuff and you only
need<br>
about 10 pounds to make a bomb the cat is already out of the bag;
I'm<br>
not sure a little more Plutonium in the world will make things
substantially<br>
more dangerous than it already is.</blockquote><br>
It depends entirely on how much Pu 240 is in it. Reactor Pu has so
much that it's a bitch to use it. Talk to the North Koreans about
it.<br><br>
A method I knew about for a decade but only made public recently will
make really pure Pu 239. If you detonate a sphere of TNT using
light and an ellipsoidal surface where the pit is at one foci and the
flash at the other, it becomes really simple to do.<br><br>
Unfortunately.<br><br>
Keith</body>
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