How Japan Plans To Build Orbital Solar Power Stations

the_newsbeagle (2532562) writes "Solar power stations in orbit aren't exactly a new idea — Asimov set one of his stories on such a space station back in 1941. Everyone thinks it's a cool idea to collect solar power 24 hours a day and beam it down to Earth. But what with the expense and difficulty of rocketing up the parts and constructing and operating the stations in orbit, nobody's built one yet. While you probably still shouldn't hold your breath, it's interesting to learn that Japan's space agency has spec'd out such a solar power station."

Comments

If you're just beaming it down to earth anyways

[mark-t]

why not just collect it from the ground in the first place?

What's going to make collecting energy on the ground from a satellite more efficient than collecting it from the sun?

Re:If you're just beaming it down to earth anyways

[Maury Markowitz]

> why not just collect it from the ground in the first place?

Exactly.

> What's going to make collecting energy on the ground from a satellite more efficient than collecting it from the sun?

In theory you don't have night, so you get twice as much hours of sunlight. Add "cosine error" and the lack of weather, and you're up to five times.

But then you have to throw away half on the way down to the earth. And then the panels last half as long in space. So in the end it's a *very* small *theoretical* advantage.

Which is, of course, utterly wiped out by the cost of launch. And everyone knows this. But the guys proposing these things are not power companies, but space companies. As is the case here, it's JAXA, the Japanese space agency. Everyone outside the space field is completely aware of the fact that this is an utterly ridiculous idea.

Re:If you're just beaming it down to earth anyways

[alexander_686]

2 reasons.

First, you don’t have to worry about your power going out at night. These things are so far away that the earth’s shadow will rarely fall on the array.

Second, in theory cells in space should be more efficient then cells buried underneath the atmosphere. I am not sure if they can overcome the practical problems to make it actually more efficient.

Side note – the US military is also looking at this. Beaming power to remote locations could be more efficient then hauling fuel. Power could be beamed to drones, giving them unlimited endurance.

Re:If you're just beaming it down to earth anyways

[Maury Markowitz]

> First, you don’t have to worry about your power going out at night

But that's not a problem we actually have. Baseload power is currently selling for 2 to 3 cents, peak power is up into the 20's. No one is going to build a space-o device to provide something we have trouble giving away.

> cells in space should be more efficient then cells buried underneath the atmosphere

Actually, the opposite is true. Cells, silicon ones anyway, are more efficient under the air. It has to do with their band gap.

> Beaming power to remote locations could be more efficient then hauling fuel

The problem is that all you're doing is replacing the array of solar panels with an array of dipoles. The increase in energy density is about 50%, so you need a field that's almost as big as normal PV. There's really no advantage here.

Re:If you're just beaming it down to earth anyways

[ubergeek2009]

The power will be transmitted as microwaves, which aren't scattered by the atmosphere as easily as visible light.

Re:If you're just beaming it down to earth anyways

[Bengie]

I would not want to be a bird or in an airplane if I passed under this satellite. They'll have to make sure they have some really good fail-safes in place in case it pivots any. I've played SimCity 2000, I've seen what a microwave power plant can do.

Re:If you're just beaming it down to earth anyways

[MetricT]

It's not a completely stupid idea, just a mostly stupid idea.

But it might make financial sense for powering McMurdo Base, for instance. The cost of hauling diesel down there is almost as ludicrous. Remote outposts and stuff.

Or if your government decided to send a small team of special forces into hostile territory, that would be a convenient way to provide them power. And you could use "cheap solar power for everyone" as good cover for launching something.

Not going to happen

[Maury Markowitz]

The numbers don't work. Period.

http://matter2energy.wordpress.com/2012/03/17/the-maury-equation-redux/

SimCity 2000?

[VorpalRodent]

If there's anything I've learned from video games, it's that this is a bad idea.

Re:Blofeld-San's new proposal approved

[Joe_Dragon]

Just trun on no disasters and it will be fine.

Corn fields?

[Hamsterdan]

Just imagine if they aim that thing at corn fields? I can see the headlines, major city destroyed by popcorn tsunami...

They should put it at L5

[karlandtanya]

Words: Bill Higgins and Barry Gehm c. 1978
Music: "Home on the Range"

Oh, give me a locus where the gravitons focus
And the three-body problem is solved,
Where the microwaves play down at three degrees K
And the cold virus never evolved.

CHORUS: Home, home on LaGrange,
Where the space debris always collects.
We possess, so it seems, two of man's greatest dreams:
Solar power and zero-gee sex.

We eat algae pie, our vacuum is high,
Our ball bearings are perfectly round.
Our horizon is curved, our warheads are MIRVed,
And a kilogram weighs half a pound. CHORUS

You don't need no oil, nor a tokamak coil,
Solar stations provide Earth with juice.
Power beams are sublime, so nobody will mind
If we cook an occasional goose.

INTERLUDE (to Oh, What A Beautiful Morning)
All the cattle are standing like statues.
All the cattle are standing like statues.
They smell of roast beef every time I ride by,
And the hawks and the falcons are dropping like flies...

I've been feeling quite blue since the crystals I grew
Became too big to fit through the door.
But from slices I sold, Hewlett-Packard, I'm told,
Made a chip that was seven foot four. CHORUS

If we run out of space for our burgeoning race
No more Lebensraum left for the Mensch,
When we're ready to start, we can take Mars apart
If we just find a big enough wrench. CHORUS

I'm sick of this place, it's just McDonald's in space
And living up here is a bore.
Tell the shiggies "Don't cry," they can kiss me goodby,
'Cause I'm moving next week to L4!

Re:But what does an actual physicist think?

[Virtucon]

While I agree with your comments I do have to point out that it's nice to set goals and to think out of the box when it comes to new ideas. Back in the 1960s we had this President that set a goal for the US in reaching the Moon, which we did. People need goals and objectives to strive for otherwise they become hopeless derelicts like Cliven Bundy.

Re:Satellites have eclipses

[Teancum]

The cost of sending 10 metric tons to LEO and about 5 metric tons to GEO is claimed by SpaceX to be slightly under $60 million USD, or about $6k/kg. That seems to be at least a competitive price (few companies say they can beat SpaceX on launch costs). From this figure, sending 10000 metric tons to GEO would be something like $120 Billion. Some cost savings could definitely happen, although the reusable Falcon 9 with all parts being reused on multiple flights is still about $7 billion each, or dropping that price down to about $14 Billion.

Regardless, a guy who knows the figures for the solar power industry, Elon Musk, who also happens to own a spacecraft launching company as well as a completely separate solar panel manufacturing company (in the form of Solar City) has repeatedly said that spaced based solar power for terrestrial consumers makes absolutely no sense and is something he refuses to become involved with because he thinks it will be a financial disaster if anybody tries to get one going.