[LINK] Five Technologies That Could Change Everything

[stephen at melbpc.org.au]

Hi David / Rachel,

Good on yuz. You certainly do appear to have Linked well-researched and
intelligent thoughts re this Wall Street Journal article, as has Rachel.

The paper has already issued a correction regarding TomK's correct point:

"Corrections & Amplifications: One thousand megawatts are enough to power 
on average about one million U.S. homes. This article on space-based 
solar power incorrectly said 1,000 megawatts could power about 1,000 
homes. — Mr. Totty is a news editor for The Journal Report in San 
Francisco. He can be reached at michael.totty at wsj.com "

So, one respectfully suggests that you email the WS Journal author, that 
is, if you haven't already (michael.totty at wsj.com) regarding your points? 

I'm sure readers might be interested in his/their response if any. As the
WSJ is certainly a respected publication one might well expect a response.

Cheers,
Stephen

> OCTOBER 19, 2009  The Wall Street Journal Cover Story By MICHAEL TOTTY 
> 
http://online.wsj.com/article/SB10001424052748703746604574461342682276898.
html>
> 
> > The technology may sound like science fiction, but it's simple:  
> > Solar panels in orbit about 22,000 miles up beam energy in the form 
> > of microwaves to earth, where it's turned into electricity and
> > plugged into the grid. (The low-powered beams are considered safe.)
> > A ground receiving station a mile in diameter could deliver about
> > 1,000 megawatts - enough to power on average about 1,000 U.S. homes.
> 

The "low powered beams" are not considered safe at all, except maybe by 
the proponents. 
If all the energy could be kept tightly focussed on the ground antenna, 
the energy density over 1 sq.mile would be 49 milli-watts/sq.cm. 
according to my calculation.
 
 This is 245 times the maximum safe level set by the ICNIRP 
(International Commission on
Non Ionizing Radiation Protection):
        10 to 400 MHz              0.20
        400 to 2,000 MHz           f/2000
        2 to 300 GHz               1.0
 
 These figures are taken from their comprehensive review of the subject 
in October 1997 -
see http://www.icnirp.net/documents/emfgdl.pdf - and Table 7 "Reference 
levels for general
public exposure to time-varying electric and magnetic fields (unperturbed 
rms values)".
 
 Of course atmospheric and electrical turbulence in the atmosphere would 
probably spray the radiation all over the place, and power would drop 
dramatically during rain.
 
Unfortunately, recommended maximum safe levels always seem to go down, 
and the health risk which always seems to surface first in any non-
commercial study is Childhood Leukemia.
 
 David

--

Cheers,
Stephen