Re: Space Based Solar - was Re: useful analogy

From: N. Thornton (bigcat_at_meeow.co.uk)
Date: 09/10/04 

Date: 10 Sep 2004 02:07:34 -0700

william.mook@mokindustries.com (william mook) wrote in message news:<407c5321.0409091644.296da583@posting.google.com>...

> Inflatable Optics
>
> http://www.de.afrl.af.mil/News/2003/03-36.html
> http://www.nasatech.com/Briefs/Jan01/NPO20952.html

neither addresses the constant rain of very high speed particles in
space, and how one could maintain inflation in a film structure under
such conditions.

Also the max size achieved so far is 1m, not 27km, according to one of
those refs. I'm sure you have answers, you always do :)

> So, we can imagine putting all the pieces together. A 500 metric ton
> satellite that consists of a disk like balloon that inflates to a
> diameter of 2.7 km and intercepts 7.7 GW of sunlight. It produces 3.1
> GW of laser energy which it beams to earth in the form of 3 million
> beams of 1 KW each. A total of 5 million users are supported at the
> same time since not all users need full power all the time.
>
> Each user on the ground paid $500 for their simple receiver. The $2.5
> billion more than paid for the satellite, the launch, and the
> receivers.
>
> The 3.1 GW of laser energy is produced 8,766 hours per year. This
> generates 27.174 billion kWh of energy. At a cost of $0.08 per watt
> this generates a revenue of $2.1 billion per year! Four years of
> income is sufficient to pay for the development costs of both the
> heavy lift launcher AND the supersized satellite it carries.
>
> Humanity uses power at the rate of around 5,000 billion watts. So, a
> 3 billion watt satellite penetrates 1/16th of a percent of the total
> energy market. Twenty satellites could supply power to 100 million
> ground stations each 1 kW rating (although only 60 million would be on
> at once full power). At $500 per ground station this raises $50
> billion. Enough to pay for the entire system. Again, at $0.08 per
> watt this generates a revenue of $42 billion per year.

I have some questions.

Average power delivey of 600w, peak 1kW, seems inadequate. It may be
posible to live on that, but no-one will choose to when there are
other options. At present in UK houses use 1kW averaged, (I mean
electricity only) with peak delivery closer to 10kW. Some houses use
upto 25kW. The old 10kW rated services are considered inadequate -
even though IRL theyre still performing satisfactorily.

There are also gas supplies for heating, again multiple kilowatt,
typically mean 3kW averaged over the whole year, so more than that in
winter.

What the conversion efficiency is for various apps I dont know, but it
wont be 100%, so your power figures seem a fair bit out.

A 10kW peak beam would be adequate for most domestic properties, if
not used for heating. Add heating and you'd need to something like
double it.

I guess you modulate the beam power according to demand, which gives
you the diversity factor. But I think youre going to need to allow
more like 3kW for domestic properties as an absolute minimum, and one
that would not be accepted today, and 10kW+ where you supply heating
power too. To gain acceptance today you'd need to provide more like
10kW peak, with, guessing here, an average of maybe 6kW if youre
covering heating as well.

Now, you have a beam providing upto 1kW or 10kW, with guard beams.
What happens to the eyes of bystanders when a tiny speck of something
metallic drifts through the air, and while the guard beam is no longer
interrupted it gets into the power beam?

Also there is the cost of the ground based conversion and control
equipment. And the many business runing costs to factor in too.

> This is enough to sustain growth until market saturation. Also to
> sustain some research into ways of expanding laser energy use,
> resulting ultimately in personal laser rocket driven vehicles and
> laser powered homes, as well as laser powered package delivery.
>
> At this point the numbers are just silly, because the economic growth
> spurred by these developments create fantastic growth. Comparing what
> might be possible is akin to comparing horsedrawn carriages and
> gaslight era industry to modern fuel injected autos and electric
> utilities - there is scant recognition of similarities. So, speaking
> of it in any useful terms paints one as a mad man.
>
> So, I've learned to be quiet. :)

I think you need to address many questions yet. I'm not saying you
havent, but people dont buy these ideas unlses you can explain it all
to them. We need a site that explains every aspect, provides realistic
figures with full costings, and most importantly explains the numerous
questions people have.

What you propose is a very big leap indeed, and would only be
considered by people if you can answer all their questions. It is when
people cant answer the relevant questions but insist that it will work
that a reputation problem occurs.

Regards, NT

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