eevBLAB 127 - Starlink as a Satellite Energy Utility?

[EEVblog]

Viewer question, just for fun: Could an array of Starlink satellites capture and transmit enough power to earth to be a financially viable energy utility? 2 minutes on DaveCAD.

[Simmed]

just even saying 100 launches to get 7000 satellite into space
my wallet hurts so bad it even vomits blood

[SiliconWizard]

TLDR; Nope.

[EEVblog]

Turns out a friend of mine has started a satellite to earth power company 
It's in stealth mode at the moment, but he contacted me and said his companies idea will pass all my calculations.
He's a wickedly smart dude, but I'd bet he's wrong.

[Lord of nothing]

Hi I did not watch the Video yet but how about reflect the Sunlight by the many Starlink Sat to an central Point in an Area like Optical Solar Farm work by reflect the Light to an Central Point who get hot?!

[Psi]

Having a satellite that can fit into starship and yet unfolds/unrolls to have a stupidly huge solar surface area seems doable.
but getting the energy down to earth efficiently and safely, without microwaving birds or accidently setting fire to things sounds practically impossible unless there is new tech.

If we had a way to safely move energy from space down to earth at over 95% efficiently it would probably be practical assuming SpaceX succeeds with starship.  The efficiently is the killer, what are you going to do with all the waste heat, that's quite a lot of thermal radiators. 

[Haenk]

Having a satellite that can fit into starship and yet unfolds/unrolls to have a stupidly huge solar surface area seems doable.
but getting the energy down to earth efficiently and safely, without microwaving birds or accidently setting fire to things sounds practically impossible unless there is new tech.

If we had a way to safely move energy from space down to earth at over 90% efficiently it would probably be practical assuming SpaceX succeeds with starship.

At the same time, how about using the same amount of money to bring that into space - and install something 100 times the size on earth? I know, this sounds crazy and likely would not attract billions of investment money...

[Psi]

I said practical not profitable   Definitely not profitable for utility power.

Depending how it was implemented, if you could push power to any spot on earth within a few hours/days notice, then perhaps that would have some profitable use cases. Mostly for military applications though.

I guess at lower power levels, and if one sat could beam power to many ground sources, there could be a use case to power remote cell sites and weather stations where there's no power available, but it would have to be better in some way than solar + batteries and that is a tall order.

Ground solar + batteries really does win out in pretty much every situation.

[Lord of nothing]

How about Laser who heat something that generate Steam?
The question is how precise can a Laser beam stearate to point them on an 1m x 1m cube?

[madires]

We have already two James Bond movies showing why lasers or focused sun light beams could be a bad idea.

[golden_labels]

Hi I did not watch the Video yet but how about reflect the Sunlight by the many Starlink Sat to an central Point in an Area like Optical Solar Farm work by reflect the Light to an Central Point who get hot?!

The mirrors concept has also been covered, even by Dave.

Above all, it’s basic geometry. A 100 m² plane intersecting light coming from sun is offering exactly the same 100 m² area no matter if we put it on Earth or in space. There is no magic there and we get no power boost for sending stuff on orbit. However, compared to placing stuff on Earth, we get enormous costs, huge resources waste, short life-span even in perfect conditions, and complexity. We also need to deal with much larger losses from transmission.

How about Laser who heat something that generate Steam?

Making it a laser doesn’t increase transmission efficiency. Putting more energy in a tighter bean gives higher energy density, but all this energy still experiences the same losses.

Assuming you meant lower-case steam,⁽¹⁾ there is an additional problem. Heat energy obtained doesn’t magically stay there. It is instantly radiated back. This isn’t a problem for traditional power generation. There the heat remains in a closed system, going “back and forth.” But in an open system it’s just going away.

The question is how precise can a Laser beam stearate to point them on an 1m x 1m cube?

Unless you wish to mount a 20 cm diameter laser or shoot Earth with X-rays: it can’t, even for a 100 km orbit. Get a laser pointer, mount it on something stable, point at a wall 100 m away. Go to that wall, measure the spot diameter.

A laser beam can be approximated by a straight cylinder only up to Rayleigh range. After that we move to a regime where it more resembles a diverging cone. For a 1 mm wide beam of IR light, this distance is a few meters.

If your first thought now is to circumvent the problem with lens focus laser, bad news. Simple geometrical optics don’t hold on that scales. EM radiation’s wavey nature shows its claws.

This has its good sides too. An extraterrestial civilization can’t cook Earth with lasers shooting from their home planet.

⁽¹⁾ Not to be confused with uppercase Steam, Valve’s platform.

[thm_w]

Hi I did not watch the Video yet but how about reflect the Sunlight by the many Starlink Sat to an central Point in an Area like Optical Solar Farm work by reflect the Light to an Central Point who get hot?!

That was what his previous video was, the guy was also smart but somehow refused to believe basic calculations.