[ExI] SpaceX Super Heavy and Space Solar

[Adrian Tymes]

On Tue, Oct 22, 2024 at 12:22 AM Keith Henson <hkeithhenson at gmail.com>
wrote:

> On Mon, Oct 21, 2024 at 4:44 PM Adrian Tymes via extropy-chat
> <extropy-chat at lists.extropy.org> wrote:
> > Caltech did it for less than $1B:
> https://www.caltech.edu/about/news/in-a-first-caltechs-space-solar-power-demonstrator-wirelessly-transmits-power-in-space
> >
> Caltech has not delivered a cent worth of power.  If you want to know
> about the topic, go to the google group Power Satellite Economics and
> search for "fraud."
>

It was not intended to deliver.  It was intended to beam something -
anything, no matter how small - and it did just that.

Denouncing something as fraud, for not delivering what it never intended to
deliver, does not seem to be a correct usage of "fraud".

>> It's $200/kW.  I worked this out 10-15 years ago. It is fine if you
> >> don't like my number. What do you calculate as a rectenna cost?
> >
> > Nonlinear.  Something that costs $200 to set up a unit that does 1 kW,
> costs much less than $200,000,000 to set up a unit that does 1 GW.
> Economies of scale set in.
>
> It is 5 GW. How much do you think a 5 GW rectenna will cost?
>

A simple way to measure economies of scale like this, is to factor in a
discount on the per-unit cost for each doubling of units.
https://en.wikipedia.org/wiki/Experience_curve_effects suggests a minimum
of 10% (usually closer to 20%) per doubling, at least for labor costs -
which would seem to account for enough of this case that at least 10% of
the total cost seems warranted.  (Ordering the raw materials in bulk also
reduces per unit costs, which is factored into this.  There is of course a
limit, but even a 5 GW rectenna seems unlikely to hit that limit.)

So if it's $200 for 1 kW, getting to 4 GW (for sake of simplicity) is 22
doublings.  0.9 to the 22nd is about 0.098, or $19.7 per kW; times
4,000,000 makes just under $78.8M, or times 5,000,000 (to answer for 5 GW)
is just under $98.5M.

Which is still a lot, but much less than $1B.  And that's conservatively
assuming only 10% per doubling.  20% per doubling comes to about $1.48/kW
for a 4 or 5 GW project, for a total of about $7.38M for 5 GW.

This is a very, very simplistic modeling of economies of scale.  You might
come up with a more refined one starting from that article.  But assuming
that, just because 1 unit of something that's being custom manufactured
would cost $X to make, 5,000,000 units will cost 5,000,000 * $X is usually
incorrect.

>  Where do you get "an average of around 1.07 GW"?
>
> net generation of 9,337 GWh  Divide by hours in a year to get the average
> load.
>

That is a misleading approach.  See again: "base load" vs. "peak load".
There are sources of power in the mix that deliver relatively constant
amounts (some only at certain times of day), and others that scale up or
down depending on demand at that time.  It  is not the case that all power
systems in the mix always, constantly, and only deliver 1/3 of their rated
capacity.

For providing power half the time, the cost per kWh would double.
>

Like so.  If you have a system that delivers peak, not just base, load then
there are further operational considerations.  Solar power satellites can,
quite easily, deliver peak loads if configured to do so, but the
operational considerations - including payback - differ from the constant
load you've been assuming.  Constant load is how you measure base load only.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20241022/5afdf7de/attachment.htm>