Beamed solar power

I've got a brainstorm and so I thought I'd share it with you.  I should mention a speculation alert and also an amateur alert.  I'm not especially qualified to discuss these matters, however, I am hopeful that some of what I post here from time to time might prove useful to someone who is.  In such a case as that, anyone is quite welcome to use these ideas and run with them, if it turns out to be an idea worth pursuing.

The idea is an offshoot of a post, which I made recently about lunar thrusters.  I got into a quandary about it because gyrotrons seemed to be too big, as we see below:

From Parkins' doctoral thesis

Besides, I don't know how useful this would be.  How long can it be fired?  It needs to be continuous, obviously if it is to supply thrust for a rocket off the lunar surface.  It would be incorporated into the device, but that is a lot of mass too.  Kinda defeats the purpose of not just burning the hydrogen and using that as reaction mass.

So, here's the idea:  The gyrotron can be pointed down to the ground, which can be used to generate power on the ground.  It would power itself off the lunar surface and all the way to a geosynchronous orbit.  From there, it will in a position to send its power to the ground.  Thus, the thing that powers it off the moon can now be used to power things on the ground, and sell it!

Then you get the benefit from mass reduction by not using oxygen, which would be otherwise lost to space. You save a piece of hardware that can continue providing useful service for years.  Now, the big question is this: can you manufacture all this on the lunar surface?  You would need a large solar power array, that can lift itself into space by way of this gyrotron.  Therefore, you will also need to manufacture the array on the lunar surface as well.

That part may not be too hard, but the gyrotron could be.

But that's not all. You need to make the rest of the hardware too, like a heat exchanger and rocket nozzle. You would need to be able to obtain all the raw materials from the lunar surface.  Some stuff may have to imported from Earth, but if you do that, you sort of defeat the purpose.  Therefore, you would have to do as much as this through in situ resourcing as possible.

Assuming all of this can be done, so what?  Wouldn't it still be too expensive?  Well, I can't answer that question, but here's the opportunity, if you can:  It costs about 60 cents per kilowatt hour equivalent in order to power an automobile.  That is assuming a 25 mile per gallon vehicle with gasoline selling for $4.00 a gallon.

Why 60 cents?  Take a battery powered auto.  Typically, they get about 4 miles per kilowatt hour.  For 25 miles, let's say that it uses 6 kilowatt hours of electricity.   If it cost 4 dollars to go those 25 miles, then the comparable cost in electricity is 4.00 as well.  Divide 4 by 6 and you get about 60 cents per kilowatt hour equivalent.

Now, all you have to do is compete against that 60 cent a kilowatt hour and you've got it made.

Not only would you need to get the satellite in orbit, you'll need to find platinum on the moon.  Your lunar platinum would be used to power the hydrogen fuel cell cars on the ground on Earth.  Here's how it could work:  Use the electricity beamed from space to synthesize methanol.  You need a source of carbon dioxide.  Easy, that is waste, anybody will let you have that.  You can synthesize the methanol from seawater and carbon dioxide.  Then transport the methanol and electrolyze it back into hydrogen at the point of sale.

Operating a fuel cell vehicle at less than 16 cents per mile would give you a competitive price with gasoline powered cars.  Since fuel celled vehicles get about 60 miles per kg, the cost per kilogram would need to be less than $9.60.  Terrestrially produced hydrogen is less than that.  But not by much.  If you can beat the 60 cents per kilowatt hour, you can beat terrestrially sourced hydrogen.  The cost per mile for the beamed energy produced hydrogen could make this an attractive alternative.

Of course, the cost of fuel celled cars are much higher, no doubt because of the cost of precious metal catalysts, such as platinum.  But that could change if rich sources of platinum are found on the moon.