[ExI] SpaceX Super Heavy and Space Solar

[Keith Henson]

On Mon, Oct 21, 2024 at 4:44 PM Adrian Tymes via extropy-chat
<extropy-chat at lists.extropy.org> wrote:
>
> On Mon, Oct 21, 2024 at 6:01 PM Keith Henson <hkeithhenson at gmail.com> wrote:

snip
>
> 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."

>> snip
>
> Beam divergence:
> θ = 1.22 * λ / D = 1.22 * 0.1224 / 1,000 ≈ 0.00149 radians
> θ = beam divergence angle
> λ = wavelength
> D = initial beam diameter
>
> Beam width at Earth's surface:
> Width = 100 + 2 * 35,768,000 * tan(0.00149/2) ≈ 6,341 meters

I think you have the half angle but it does not matter.

 snip

>> 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?

snip

>  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.

I don't see any discussion of base vs. peak loads in that article.
>
> That said, in practice you wouldn't be offsetting literally everything right away.  Base load service is far more economical than peak load, and energy storage solutions are being investigated to take care of the discrepancy - but investigating power storage (on the ground, anyway) gets away from discussing the power satellite system itself.  I assume your calculations are primarily to serve base loads, which generate around the clock (or close to it).

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

If you work out the cost of a rectenna, please make it public.

Best of luck.

Keith
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