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How Japan Plans To Build Orbital Solar Power Stations

timothy posted about 3 months ago | from the start-up-and-build-down dept.

Space 230

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."

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230 comments

Blofeld-San's new proposal approved (1, Interesting)

sandbagger (654585) | about 3 months ago | (#46842177)

Seriously, this is right out of a James Bond story. What amazing times we live in.

Re:Blofeld-San's new proposal approved (0)

Anonymous Coward | about 3 months ago | (#46842381)

beaming solar energy down to earth. sounds suspiciously like an ion cannon.

Dr. Evil: Back in the 60's, I developed a weather changing machine which was in essence a sophisticated heat beam which we called a 'laser.' Using these 'lasers' we'd punch a hole in the protective layer around the world which we called the 'ozone' layer. Slowly but surely ultraviolet rays would pour in, increasing the risk for skin cancer, that is...unless the world pays us a hefty ransom?

Re:Blofeld-San's new proposal approved (0)

Anonymous Coward | about 3 months ago | (#46842409)

But will they be able to withstand a tsunami?

Re:Blofeld-San's new proposal approved (3, Funny)

Joe_Dragon (2206452) | about 3 months ago | (#46842435)

Just trun on no disasters and it will be fine.

Re:Blofeld-San's new proposal approved (0)

Anonymous Coward | about 3 months ago | (#46842611)

FUND FUND FUND

Re:Blofeld-San's new proposal approved (1)

K. S. Kyosuke (729550) | about 3 months ago | (#46842855)

That would be a Sun-ami [wikipedia.org] , right?

Re:Blofeld-San's new proposal approved (2)

jcomeau_ictx (696704) | about 3 months ago | (#46842877)

_Dark Rivers of the Heart_ by Dean Koontz. the sat is nicknamed Godzilla and a programmer, Ellie, has a backdoor into it. great book.

If you're just beaming it down to earth anyways (3, Insightful)

mark-t (151149) | about 3 months ago | (#46842229)

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 (4, Interesting)

Maury Markowitz (452832) | about 3 months ago | (#46842359)

> 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 (1)

mark-t (151149) | about 3 months ago | (#46842613)

I get how collecting energy in space can be more efficient than collecting it on the ground, but if you actually have to beam it down to earth in the first place, you are going to have to transmit it through the same atmosphere that would reflect and absorb so much of the sun's energy in the first place. Although I can see the theory of not having a night giving additional power, for everything else you are still ending up trying to collect energy on the ground from space, which seems fundamentally no different than collecting it from the sun directly.

Re:If you're just beaming it down to earth anyways (4, Informative)

ubergeek2009 (1475007) | about 3 months ago | (#46842655)

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 (4, Funny)

Bengie (1121981) | about 3 months ago | (#46843039)

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 anyway (0)

Anonymous Coward | about 3 months ago | (#46843149)

Oops

Re:If you're just beaming it down to earth anyways (0)

Anonymous Coward | about 3 months ago | (#46843379)

Very, VERY wide beams. You just need something big to collect it. It wont actually even be noticeable, besides that, are you REALLY trying to relate a video game to reality?

Re:If you're just beaming it down to earth anyways (0)

Anonymous Coward | about 3 months ago | (#46843213)

So I guess the design of a fail-safe, automatically self-repairing multi megawatt microwave transmitter is a solved issue? How efficient would it be?

Oh sorry, so you'd be scheduling regular maintenance and repair trips? In geostationary orbit?? Or perhaps you were planning on sending up a 3D printer and just upload new parts? I'm having hard time keeping track of all the fantasies and delusions that software people have...

One tiny little question, the light pressure on this giant solar array, how will it be compensated? You know, the same light pressure that's supposed to drive solar sails to other stars? So, will we 3D print a reaction system to keep the panel oriented? Hmm? Oh OK, we'll just add some ion thrusters every few meters... Oh, how are you going to refuel it? More 3D printers?

Wait, something so large and thin would probably wave like a flag if the thrusters aren't all firing at the same time... Hmmm!

But isn't the Earth under imminent threat of being wiped out by the Death Asteroid? But I guess this large panel is immune to meteorites??

Re:If you're just beaming it down to earth anyways (2)

cpaalman (696554) | about 3 months ago | (#46843555)

>> So I guess the design of a fail-safe, automatically self-repairing.......

So I guess you didn't RTFA did ya now?

>> Oh sorry, so you'd be scheduling regular maintenance and repair trips? In geostationary........

Oh sorry, you couldn't be bothered to RTFA to answer your silly questions?

>> One tiny little question, the light pressure on this giant solar array, how will it be.......

One tiny little question, did ya RTFA?

>> Wait, something so large and thin would......

Wait, something so easy as RTFA is too challenging, but spouting off about engineering issues, to which I'm sure you are an expert, not so much.... Hmmm!

>> But isn't the Earth under imminent threat of being wiped out by the......

But isn't Earth under imminent threat from ignorant people who don't RTFA before spouting off??

Re:If you're just beaming it down to earth anyways (1)

LifesABeach (234436) | about 3 months ago | (#46843217)

I know it sounds goofy, but has anyone thought of an Aeral Wire Tether [wikipedia.org] ? At least there's some support evidence using this.

Re:If you're just beaming it down to earth anyways (1)

alexander_686 (957440) | about 3 months ago | (#46843277)

I am missing your point. The article does mention using a tether to stabilize the solar array. Are you thinking about electric production? I can be used as such but unfortunately producing electricity robs one of delta, which drops your orbit – eventually into the atmosphere. There is no such thing as a free lunch. Most suggestions I have seen is to pump electricity into the tether to increase delta.

Re:If you're just beaming it down to earth anyways (1)

WillAffleckUW (858324) | about 3 months ago | (#46843401)

I know it sounds goofy, but has anyone thought of an Aeral Wire Tether [wikipedia.org] ? At least there's some support evidence using this.

Yes, I think al-Qaeda proposed that, as an interesting method of doing things.

seems fundamentally different than collecting it f (0)

Anonymous Coward | about 3 months ago | (#46843233)

It is different in a number of ways. You can transmit the power down in a band of the spectrum that has very little loss instead of the total integrated loss of the atmosphere. As long as your conversion doesn't waste more energy than would be lost in the atmosphere then this is a win. You can receive the down transmitted signal on a grid that is not incapacitated by environmental conditions like dust and heat like solar cells are. The cells in space won't get dusty/ scratched and need to be cleaned or polished twice a week. Hurray for spectrally avoiding losses.

Re:seems fundamentally different than collecting i (0)

Anonymous Coward | about 3 months ago | (#46843339)

Hurray for ignoring every other issue! Space Nutters, you gotta love 'em!

Re:If you're just beaming it down to earth anyways (3, Interesting)

MetricT (128876) | about 3 months ago | (#46843073)

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.

Re:If you're just beaming it down to earth anyways (1)

SailorSpork (1080153) | about 3 months ago | (#46843199)

They had these in SimCity 2000 [wikia.com] . You built Microwave power collectors that collected energy from orbital space stations.

Why I'm bringing it up on Slashdot (aside from the hoped-for karma boost from invoking PC game nostalgia) is that occasional disasters happened if the orbital satellites were ever off by a fraction of a percent and they beamed the energy into the nearby residential population instead.

I'd be very interested to know more details of how they plan to transport the energy to the surface.

Re:If you're just beaming it down to earth anyways (0)

The Cat (19816) | about 3 months ago | (#46843275)

Hey look, everyone! Someone came up with a new idea that might advance science and Slashdot immediately claims it will never work!

How far up your ass did you reach to pull "half the energy is lost on the way down" out and try to sell it as fact?

These are the same people who get their underwear all in a wedge when other people criticize science or oppose scientific advances.

Scientism followers are self-congratulatory fundamentalist paranoid hypocrites.

Re:If you're just beaming it down to earth anyways (3, Interesting)

alexander_686 (957440) | about 3 months ago | (#46842371)

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 (0)

Anonymous Coward | about 3 months ago | (#46842505)

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

We already don't.

Second, in theory cells in space should be more efficient then cells buried underneath the atmosphere.

If we had the energy to build the thing, we wouldn't have an energy problem.

Power could be beamed to drones, giving them unlimited endurance.

Sure, I guess if you don't need to run a profit, you can spend billions to keep a magical drone flying longer, you know, instead of just flying a few extra drones.

Re:If you're just beaming it down to earth anyways (4, Informative)

Maury Markowitz (452832) | about 3 months ago | (#46842511)

> 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 (1)

alexander_686 (957440) | about 3 months ago | (#46842789)

Your point on base load is a bit off point. Base load is cheap because it uses coal or nuclear. If you want be to carbon neutral or want to close down all of your nuclear plants, those things go away so your cheap base load goes away. And as of today we don’t have any good way to store electricity generated during the day for night time use. Yes – I will acknowledge that there are some interesting projects out there, but nothing cheap enough for prime time today. This would be a solution – abet an exotic one.

Space is theoretically more efficient. Period. You don’t have an atmosphere absorbing the sunlight. You point out some practical issues but that does not detract that space is theoretically more efficient. Poke around the interesting and you can find plenty of interesting solutions. Some are table top demonstrators while others boarder on science fiction. But I will stand that on theory it is better. I can’t say if we can overcome the practical aspects.

On solar for the military, you have to deal with nighttime storage issues and operations during the winter where there is little sunlight. Space based would avoid these issues. Solar is not a slam dunk.

Does space based power have formidable challenges? Yes. Will it likely happen? No. However we should all have a soft spot for long term projects that try to hit a home run with creativity. As a reminder, today is DNA’s 61st birthday. Without some wild and crazy experiments we would never have found the double helix.

Re:If you're just beaming it down to earth anyways (1)

Maury Markowitz (452832) | about 3 months ago | (#46843245)

> Base load is cheap because it uses coal or nuclear

Or wind, or hydro, or pumped storage, or tidal power or natural gas or geothermal or lots of things. Fallacy of the excluded middle.

Last night demand in Ontario dropped to 12.3 GW. That is less than the minimum amount of power the grid can generate. So in order to get rid of that power, they sold it for, literally, zero cents.

No one is going to build a device who's only selling point is that it produces more of this stuff.

> Space is theoretically more efficient. Period

The band gap of silicon solar cells is in the near IR, which means any light above that frequency is increasingly inefficient in capture. They capture less than 1/2 of the power from blue light, for instance. By down converting some of the light from higher frequencies, the atmosphere increases photocurrent. Typical cell designs are about 14% efficient in space and 16% on the surface.

> You don’t have an atmosphere absorbing the sunlight

That's not efficiency, that's photocurrent.

Re:If you're just beaming it down to earth anyways (1)

mark-t (151149) | about 3 months ago | (#46842687)

But for point 2, you are still having to ultimately try to collect that energy on the ground anyways. It would be fine for collecting energy in space that you were using in space, but if you are beaming it to the ground anyways, I really don't see a fundamental difference between that and just collecting it from the sun from the ground.

That said, I can see how it could provide almost 24 hour access to energy (point 1), although I'm not exactly sure that you'd really collect sigificantly more energy doing things that way than you would just collecting energy on the ground directly from the sun in the first place, since in both cases, you are still dealing with ground-based collectors... and although the space-based collectors might be very efficicent, unless they actually approached 100% efficiency, I'm not sure that after transmitting the energy to ground-based collectors on earth, you'd get anywhere close to twice the amount of energy out of them just because you happen to be able to collect energy any time of day or night.

Re:If you're just beaming it down to earth anyways (1)

Rockoon (1252108) | about 3 months ago | (#46842719)

I really don't see a fundamental difference between that and just collecting it from the sun from the ground.

Why dont you? have you even considered how it would be transmitted? Apparently not, because you seem to think we will have a flashlight in space shining light on the earth.

Re:If you're just beaming it down to earth anyways (1)

alexander_686 (957440) | about 3 months ago | (#46842859)

Sunlight is broad spectrum and some of it will be absorbed by the atmosphere, clouds, etc..

The idea is to shift the energy from a broad spectrum to a wavelength, like microwaves, which are not absorbed. In theory one can squeeze more energy out. Now, we are talking about sunlight => electricity => microwave output => microwave reception => electricity, so there are known issues that need to be resolved.

Re:If you're just beaming it down to earth anyways (1)

jellomizer (103300) | about 3 months ago | (#46842841)

First. You can put the satellite so it will always be facing the sun... However, you will need a strip of power receivers that strips across the world. otherwise you will get a large block of rock call the Earth getting in the way of beaming the energy. You may be able to store it then blast it out every day. However energy needs of the world require longer spread out energy. That is why we don't power stuff by lighting.

Second. When you beam the energy back, that energy is going to go threw clouds and weather, perhaps fry a bird or two. So a lot of that energy gained will be loss.

Third. The military isn't really a model of effective energy. They will sacrifice a lot of power efficiency if it gives them a tactical advantage.

Re:If you're just beaming it down to earth anyways (1)

alexander_686 (957440) | about 3 months ago | (#46842941)

First, geosynchronous orbit. It will always point to the same spot on earth. (There are issues – see the article for depth.)

Secondly, microwaves are not much affected by the atmosphere, clouds etc. I don’t think the odd bird would have much effect. Not saying there won’t be an effect on the bird.

Third - well yes. It is the Department of Defense and not the Department of Energy which is pursuing this in the US. What may be impractical for daily electric consumption may be practical on the battlefield..

Re:If you're just beaming it down to earth anyways (1)

i kan reed (749298) | about 3 months ago | (#46842971)

Or a network of satellites that can transmit to eachother, and the nearest ones transmit to ground.

Re:If you're just beaming it down to earth anyways (0)

Anonymous Coward | about 3 months ago | (#46843657)

Than.

The word you are looking for is than. It's not really so terribly difficult, is it?

Re:If you're just beaming it down to earth anyways (2)

gstoddart (321705) | about 3 months ago | (#46842585)

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

Probably the ability to do it for more hours than you would have daylight?

If there exists an orbital path which can see the sun 24 hours/day, and that same orbital path lets you see the receiving stations, say, 18 hours/day ... you get more access to sunlight than you would otherwise.

Besides, it has the added benefit that if your neighbors get a little uppity, you let your mirrors slide a little off course and get a little more tightly focused ... bam, instant death ray. And, that's where the real money is. ;-)

Re:If you're just beaming it down to earth anyways (1)

kasperd (592156) | about 3 months ago | (#46843097)

If there exists an orbital path which can see the sun 24 hours/day, and that same orbital path lets you see the receiving stations, say, 18 hours/day

You can swap those and look for an orbit that can see the receiving station 24 hours/day and the sun more than 18 hours/day. Geostationary orbit would be an option covering both. To not have a period at night, during which you receive no power, you could have two satellites at different points in geostationary orbit pointed at the same receiving station. Then you will have two periods during the night where only one receive power, but you could position the satellites such that those periods happen when power usage is lowest. The tilt of the Earth's axis might even ensure that the problem of losing power at night is only an issue at certain times of the year.

I am just wondering when (if ever) geostationary orbit will get too crowded.

Re:If you're just beaming it down to earth anyways (0)

Anonymous Coward | about 3 months ago | (#46842619)

The satellite is basicly a concentrator. It's big so it can collect the inefficiently dispersed solar radiation and concentrates it into a laser beam that can be collected by a smaller ground based station. Theoretically the losses du to conversion can be mad up by using a bigger satellite array.

It's similar to putting a sun-tracking mirror array up to focus light onto your photovoltaic panels (collects more light for longer with a smaller photovoltaic).

Re:If you're just beaming it down to earth anyways (1)

CrimsonAvenger (580665) | about 3 months ago | (#46842627)

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

Without speaking to the economic feasibility of the idea in general, the advantages over a groundside installation are three-fold (or maybe 2.5-fold):

1) There's more solar radiation up there, since the atmosphere doesn't block it.

2) The sun doesn't set on the orbital installation nearly so often as on a ground station. A ground station has to deal with darkness half the time (more in winter, less in summer, of course), plus lessened efficiency early and late in the day, when the panels aren't aligned with the Sun. An orbital installation lose a few hours of daylight every six months at the equinox, and can remain aligned properly with the Sun at all times for maximum efficiency).

3) It takes up less of your limited real-estate to put the solar collector in orbit. Yes, you need a large area receiver on the ground, but, given microwave transmission from orbit, the area UNDER the receiver is still useful for farming, parks, that sort of thing (hell, people could live there safely, but the anti-solar-satellite whackjobs that WILL appear if someone tries this will scream to high heaven about the incredible dangers).

Re:If you're just beaming it down to earth anyways (1)

mark-t (151149) | about 3 months ago | (#46842733)

Point 1 is moot.... since you are going to try to transmit the energy back down to earth anyways... The atmosphere is going to be just as effective at blocking the energy from the satellites as it is from the sun... possibly even moreso, since the satellites will not actually be transmitting as much energy as the sun can potentially provide.

Point 2 I can see the merit behind... but unless the satellites approach a hundred percent efficiency, I'm still not sure you'd see significant gains over collecting energy from the sun directly using ground-based collection.

For point 3, see point 1.... you still need ground-based collection anyways... unless you are only using the energy in space, it does not make any sense to expect transmitting the energy from a satellite to earth to somehow magically be more efficient or superior to collecting the energy from the sun directly using ground-based collection.

Re:If you're just beaming it down to earth anyways (1)

CrimsonAvenger (580665) | about 3 months ago | (#46843015)

Nah, we can transmit down from the sat using a different part of the spectrum that the atmosphere is more transparent to.

As to the ground-based receptors - you can, for instance, block microwaves with a mesh that is mostly transparent to visible light. Which means a microwave receptor can be mostly transparent to visible light. Which allows you to use the land under the receptor (if you put it, say, ten feet off the ground) in pretty much any way you desire - grow wheat, corn, cows, etc.

Re:If you're just beaming it down to earth anyways (1)

Maury Markowitz (452832) | about 3 months ago | (#46843295)

> Nah, we can transmit down from the sat using a different part of the spectrum that the atmosphere is more transparent to.

That's not what he's saying. He's saying that you're more efficiently transmitting a tiny amount of the available power, instead of less efficiently transmitting *all of it*. Unless you propose covering a patch of the sky the same area as the surface of the Earth facing the sun, it is unlikely you will be able to change this.

> Which allows you to use the land under the receptor (if you put it, say, ten feet off the ground) in pretty
> much any way you desire - grow wheat, corn, cows, etc

Which we do all the time with solar panels already. It's called "solar crop sharing" or "solar cropping". Actually, there's a good article on this in the sidebar of the JAXA article that is the basis for this post.

Re:If you're just beaming it down to earth anyways (2)

DerekLyons (302214) | about 3 months ago | (#46842721)

A satellite in geosynchronous orbit is in daylight essentially 24/7/365. A solar panel on the ground.... isn't.

That being said, this is about as newsworthy as yet another Bennet Hazelton bloviation. Solar power sats have been spec'd out by any number of agencies or organizations with the engineering chops to do so, and they all come a cropper on the same issue - it's simply too goddam expensive to boost the satellite's components into orbit.* Even SpaceX's most fevered dreams of how low they can reduce the costs ends up being too expensive by a wide margin. Not to mention that even adding another 9 or two to the current dismal reliability** of space launchers not only vastly increases the cost, but due to the number of launches required still means you're almost certain to lose at least one of your payloads.

* No, building out asteroid or lunar mining technology isn't much help due to the immense cost of doing so.

** On average, somewhere between .94 and .96 for mature launchers.

Re:If you're just beaming it down to earth anyways (1)

CrimsonAvenger (580665) | about 3 months ago | (#46843267)

the current dismal reliability** of space launchers

** On average, somewhere between .94 and .96 for mature launchers.

And yet the Shuttle program was shutdown with a 98+% reliability rating - two failures in 135 launches.

Which is why we've been hitching a ride with the Russians on the much more reliable Soyuz, which has had only two failures in 120 launches....

Re:If you're just beaming it down to earth anyways (0)

Anonymous Coward | about 3 months ago | (#46842757)

What makes you think they want to send the collected energy back to Earth?

Re:If you're just beaming it down to earth anyways (2)

mark-t (151149) | about 3 months ago | (#46842975)

The article.

Mirrors in orbit would reflect sunlight onto huge solar panels, and the resulting power would be beamed down to Earth.

Re: If you're just beaming it down to earth anyway (1)

jxander (2605655) | about 3 months ago | (#46842955)

Pretty soon (for various values of "soon") we're going to need power in space.

NASA is planning asteroid capture. Assuming it goes well and we don't kill ourselves, the next step is to mine the asteroid and use the raw materials to build a bigger Space Station or Lunar Base. Both of which will benefit tremendously from orbital solar platforms.

If we can get some power here on earth in the meantime, all the better.

Re: If you're just beaming it down to earth anyway (0)

Anonymous Coward | about 3 months ago | (#46843357)

Wow, what's for lunch at Menninger's today?

Agreed: Start Here First (1)

xdor (1218206) | about 3 months ago | (#46843115)

Re:Agreed: Start Here First (1)

mark-t (151149) | about 3 months ago | (#46843159)

Not a terribly useful link if one does not subscribe to new scientist. Only the first paragraph is readable. The rest requires a subscription.

Re:Agreed: Start Here First (1)

xdor (1218206) | about 3 months ago | (#46843329)

Yeah, I noticed that after I posted it... here's more about the foundation trying to do it:

http://en.wikipedia.org/wiki/D... [wikipedia.org]

Re:If you're just beaming it down to earth anyways (1)

R3d M3rcury (871886) | about 3 months ago | (#46843495)

Well, in Japan's case, you have the problem where there isn't much ground to collect energy from. Sure, here in the US, we have great big wide open spaces where we could put solar collectors.

And we'd really rather that they not start trying to collect more land...

Re:If you're just beaming it down to earth anyways (1)

Pinky's Brain (1158667) | about 3 months ago | (#46843667)

Plenty of ocean though ...

Re:If you're just beaming it down to earth anyways (0)

Anonymous Coward | about 3 months ago | (#46843573)

I went to a conference on this topic and have lots of experience in RF/DC conversion.

I personally am torn on the topic in terms of cost/MW, but John Mankin made a case for it at the conference but I'm still of the opinion we could just solve the problem by installing more ground based solar. Japan is a bit more unique in this problem as they don't have as much land available to them for solving the problem via brute force. The main arguments for space based solar otherwise are the following:

a) 24/7 sun exposure. You can have the main transmitter satellite in geostationary orbit providing a lot of Sun light exposure and by using the large mirror arrays the solar-to-RF conversion station will always receive sun light even when in Earth's shadow. You also avoid the cloud cover problem by placing the solar array in orbit.
b) increased solar flux. You don't have the atmosphere absorbing half the light so you get much more sunlight per m^2.
c) no pollution supposedly.

Of these 3 points really only A holds completely true. Transmitter and receiver losses from DC-to-RF-to-DC conversion efficiency and side lobe losses obviously play a big role but the gains from the increased solar irradiance and 24 hour exposure supposedly makes up for it. With B you still get microwave transmission losses through clouds, especially clouds with very high moisture content. It's going to absorb most of the beam if it's a large rain cloud, but this is resolved by using a phased array beam to pick a receiver station with no cloud cover. Then there's point C - no pollution. It could take an awful lot of rockets to put all that equipment in orbit, considering the cheapest way for an unmanned flight would be using solid rockets.

So if we take all these issues into account is it really worth the cost and effort? When we could not build rockets and just put solar panels with batteries on every rooftop or cover a desert with them. Receiver stations will still be on the order of a km or more wide because a phased array beam at the desired frequency can only be so narrow, also the power density of the beam can't be too high otherwise you start cooking things or forming a plasma cloud in the upper atmosphere which will gobble up all the RF energy.

I can probably keep going on about all the issues. Best of luck to JAXA, I would love to see this work.

But what does an actual physicist think? (0)

Anonymous Coward | about 3 months ago | (#46842235)

http://physics.ucsd.edu/do-the... [ucsd.edu]

Besides, the Japanese like to announce grandiose projects that are just vaporware.

http://www.cnn.com/TECH/9705/2... [cnn.com]

We just had a 3D printing smackdown story, why are geeks such naive daydreamers?/

Re:But what does an actual physicist think? (3, Insightful)

Virtucon (127420) | about 3 months ago | (#46842591)

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. [politico.com]

Re:But what does an actual physicist think? (1)

roman_mir (125474) | about 3 months ago | (#46843001)

Sure, people need goals and objectives and they need the FREEDOM to set those goals and objectives in their own lives by themselves, they don't need ANY activist, destroying privately generated wealth on insane collectivist ideology proposals, be that wars or Moon landings.

If somebody wants to land on a Moon privately, let them build a company and collect money from like-minded individuals to fly there. Let free people actually be free people for once.

Re:But what does an actual physicist think? (0)

Anonymous Coward | about 3 months ago | (#46843385)

Oh boy, you're nuttier than Planter's Party Mix!

Re:But what does an actual physicist think? (0)

Anonymous Coward | about 3 months ago | (#46843597)

Sure, people need goals and objectives and they need the FREEDOM to set those goals and objectives in their own lives by themselves, they don't need ANY activist, destroying privately generated wealth on insane collectivist ideology proposals, be that wars or Moon landings.

Nonsense. The success of 19th century Gilded Age did not come from people given freedom. The US went from backwater former colony to global economic super power because only a few elites had freedom. Elites being the government and robber barons, most of whom were connected to government (i.e Carnegie had a nice relationship with the feds because he helped them in the Civil War, the Pinkertons rose to prominence because they offered security to the feds)

If you weren't one of the elites, you had very little freedom. You a common worker? Then the company town is good enough for you. If you try to join or create union we'll send the Pinkertons after you, or we hire cheap Chinese workers to replace you

Speaking of Chinese, there's another bunch that had little freedom. The government actively wrote laws against them, because they know if left with freedom to start their own businesses, the Chinese would out compete most Caucasians. For example, it used to be illegal for a Chinese immigrant to own land in California, so they can't own their own farm. There were also laws against what type of boats and sails you can use (read: not the efficient Chinese ones), greatly limiting the Chinese ability to participate in the fishing industry. Stuff like this kept the wages of Chinese low, allowing the robber barons to hire them and build up the American economy, most famously with the construction of the transcontinental railroad.

"Let free people actually be free people for once"? That's totally un-American

Re:But what does an actual physicist think? (1)

robmv (855035) | about 3 months ago | (#46842833)

“Anything one man can imagine, other men can make real.”
  Jules Verne, Around the World in Eighty Days

Re:But what does an actual physicist think? (0)

Anonymous Coward | about 3 months ago | (#46842963)

That's such a glaring fallacy I'm surprised anyone past high school would say it. I can imagine living 200 years with the body of a 25 year old, I can imagine a leisure society where everyone actually benefits from our technology, I can imagine flapping my arms and flying to the Moon.

Sounds a little scary (1)

mi (197448) | about 3 months ago | (#46842241)

From TFA:

Several giant solar collectors in geosynchronous orbit are beaming microwaves down to the island from 36 000 km above Earth.

What if they miss the aim one day by half a degree — the beam hits outside of whatever is supposed to process it dirtside? What will the effect be — and how far away must that island be located for reasonable level of safety?

Re:Sounds a little scary (1)

Virtucon (127420) | about 3 months ago | (#46842657)

Not as scary as Godzilla.

SimCity (1)

Neruocomp (513658) | about 3 months ago | (#46842259)

Because well all know what happens

How is it beamed down again (1)

Anonymous Coward | about 3 months ago | (#46842291)

Oh yeah, microwave. Nice, a high energy microwave death ray in space. Good idea.

Re:How is it beamed down again (1)

lister king of smeg (2481612) | about 3 months ago | (#46842635)

Really they don't plan to use it a giant space based death that could easily be pointed at North Korea, Shanghai, no its just to beam a metric shit-ton of power to them really, oh the on board missiles and armor plating are just there to keep the space junk from breaking it.

Why? (0)

Anonymous Coward | about 3 months ago | (#46842319)

How is shooting up a panel to orbit better than leaving it on the gound? Ok, it's direct sunlight 24/7, but that's like what, a 8x increase in output? Compared to the 100000x inrease in cost, it's not really worth it.

Re:Why? (0)

Anonymous Coward | about 3 months ago | (#46842729)

Because it's in space? That automatically makes it cool and better somehow. Because of the space propaganda we saw as kids, I suppose.

Not going to happen (4, Insightful)

Maury Markowitz (452832) | about 3 months ago | (#46842321)

The numbers don't work. Period.

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

Re:Not going to happen (0)

phillk6751 (654352) | about 3 months ago | (#46842477)

That equation is assuming PV cells are being used in the orbital station...if you RTA, they appear to want to collect light, and direct it towards earth to a ground-based generator that will convert the light into electricity.

Re:Not going to happen (1)

phillk6751 (654352) | about 3 months ago | (#46842541)

Oops my bad...i should have RTFA...i saw the pic and thought they'd be reflecting light....this idea probably wouldn't work....wow

Re:Not going to happen (1)

Maury Markowitz (452832) | about 3 months ago | (#46842885)

> Oops my badi should have RTFA...i saw the pic and thought they'd be reflecting light

No, you're right, that's definitely what the image implies.

As to the concept of using mirrors, some points

One is that conventional cells max out at about 1.1 "suns", meaning that if you shine more than another 10% light on them you flatline the power. It has to do with the speed of the charge carriers, they can only move so fast and after you get to some point where the incoming photo creates an electron that immediately hits a hole from the last photon.

But that said, you can still double the total production because you can get sunlight at night. Actually it's more like 4 times because you can dispense with the "trackers" on the ground and use fixed-mount panels, which saves a whole lot of money and space. So personally, I'm more than a little surprised this isn't the path people are exploring.

Re:Not going to happen (1)

bsolar (1176767) | about 3 months ago | (#46843265)

Can't you "disperse" the concentrated light on more panels once it reaches the ground station to avoid the 1.1 "suns" limit? Another way might be to avoid photovoltaic panels and use the concentrated light to boil water.

Re:Not going to happen (1)

rsborg (111459) | about 3 months ago | (#46842487)

The numbers don't work. Period.

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

So you're assuming this isn't a weapons platform? I mean, there aren't any real strategic benefits to being on the top of a gravity well, are there [1]?

[1] http://en.wikipedia.org/wiki/T... [wikipedia.org]

Re:Not going to happen (0)

Anonymous Coward | about 3 months ago | (#46842633)

Quoting sci-fi to justify fantasies is the last resort of the incompetent. If you have the energy to put something up in orbit, you have the energy to use it directly as a weapon, no need to go through a complex Rube Goldberg contraption...

Re:Not going to happen (1)

rasmusbr (2186518) | about 3 months ago | (#46842715)

When you consider the energy cost of launching the equipment into space (0.5*mass*speed^2) you also find that the system is possibly an energy sink depending on how heavy the equipment is and how efficient your space launch system is. You'd basically need a really good and optimized space elevator to even have a chance at having an energy source.

Every penny of space research that isn't spent towards making space launch cheaper and more efficient should be looked at with some suspicion.

Re:Not going to happen (0)

Anonymous Coward | about 3 months ago | (#46842947)

Maury,

Thanks for the well reasoned article, I don't think your apples=apples approach works here. The Japanese don't have a Nevada to put vast solar arrays into, and everything they get by way of oil or coal has to be shipped to them at an additional cost. They also have a reluctance to embrace any further nuclear technology. I'm certain this changes what they are willing to pay to be energy independent.

I'm not certain if the nameplate rating or the insolation should be affected most in your equation, but the energy received from the sun in space is stronger before it is weakened by passing through the atmosphere. Your Insolation numbers seem to indicate a 6 hour day on earth with a 24 hour day in space, while that may in fact be the real world numbers for collecting sunlight, I think the panels are being hit with different amounts of energy depending on which side of the atmosphere they are on. I don't know that the additional sunlight gained counters the transmission losses later, but it is a factor.

Since one of the biggest factors in your arguement (not counting cost to orbit) is the lifetime of the panel I wonder if concentrated solar wouldn't work better, the mirrors wouldn't degrade at the rate the panels do. Yes could just as easily use concentrating solar on earth (conentrated solar thermal seems a better bet than PV anyhow) but the money spent on sending new panels to space would be cheaper than replacing an entire array. If I had a component that degraded 3x faster in space than on earth, I believe I would choose a design that maximizes the utility of that component. Mirrors have been in use continually on earth since the 60s and 70s in solar thermal applications with no degradation.

Tekfactory posting as AC because work filter hates /.

Re:Not going to happen (2)

Maury Markowitz (452832) | about 3 months ago | (#46843643)

> The Japanese don't have a Nevada to put vast solar arrays into

It is important to note that the safely limits for microwave radiation is about 10 mW/cm^2. It is widely assumed that this number would be increased for a SPS system, and the baseline figure is 23 mW/cm^2. That compares to about 90 to 110 mW/cm^2 for "bright direct sunlight" under AM1.5 to AM1 conditions.

Let's examine the numbers. The article speaks of a collector "3 kilometres long". Let's assume, for the math, that this is the diameter of a circular collector, so that would be pi x 1500^2, or about 7 million square meters. In Japan, which is just about exactly AM1.5, that's 900 W/m^2, so that's 6.3 GW of power falling in that area. If covered with conventional panels with an arial efficiency of 16%, which is common these days, then this array using ground-mounted panels would generate 1.8 GW of power.

Now how much power is their design supposed to generate? 1 GW.

So you see the problem Now admittedly the *daily* energy produced would be about 24 GWh for the SPS and about 10 to 16 GWh for the solar panels (the upper limit assumes trackers). But I think you will agree that the small increase in size needed to cover that gap in total production, assuming you even want that (no one wants power at night, we're sleeping) is never ever ever ever going to cost less than the satellite. Even in Tokyo!

> but the energy received from the sun in space is stronger before it is weakened by passing through the atmosphere

About 25%, which is mostly reflection and scattering. Some of that you get back as diffuse blue-sky radiation. Overall it's much smaller than you might think - you can see the sun after all, think about what that actually means. Offsetting this is the drop in efficiency of the cells due to the spectrum, which is from 16 to 14%. This makes up a good chunk of what's left. In the end, it's pretty much a wash, maybe a few percent, at best.

> Your Insolation numbers seem to indicate a 6 hour day on earth with a 24 hour day in space

Those numbers include EVERYTHING. And I mean EVERYTHING, I mean everything from direct sunlight to diffuse sunlight to reflections off snow to dust on the panels to clouds in the sky to whether or not its cloudier in the morning or afternoon where you live to losses in the wiring to reflections off the glass on the front. If you can think of a loss mechanism, its accounted for in there.

> the mirrors wouldn't degrade at the rate the panels do

Go read the wiki article on space debris (which I basically wrote) and look at some of the images. Are you still so sure?

Trust me, I've looked at this issue six ways to Sunday. It cannot possibly work.

Re:Not going to happen (0)

Anonymous Coward | about 3 months ago | (#46843131)

We have a nut job with a blog marked naming equations after himself as insightful? Really slashdot? I may be an anonymous coward but at least my opinion isn't clickbait.

Re:Not going to happen (0)

Anonymous Coward | about 3 months ago | (#46843475)

As opposed to the very reasonable proposal of sending more material into space than the entire species has launched in total so far, is totally not nuts and certainly not clickbait either....

Japan might need to (1)

bigpat (158134) | about 3 months ago | (#46842335)

If Japan wants to move away from nuclear power, then space based solar might be the only alternative. Reliance on foreign oil has been a big drain on their economy since shutting down their nuclear power plants after the 2011 Tohoku earthquake and tsunami. The tension with China over the senkaku could be a direct result of increasing pressure to do oil and gas exploration in the surrounding waters. Regardless of Global Climate Change because of burning fossil fuels, we would all be better off if Japan could move away from fossil fuels, either back to nuclear and/or with more geothermal and even space based solar.

Only six challenges to build an SPS? (1)

Ihlosi (895663) | about 3 months ago | (#46842339)

What about "Not having the thing clobbered by space junk"?

What? No Vanquish reference? (0)

Anonymous Coward | about 3 months ago | (#46842389)

http://youtu.be/Gb-QEJ6y0QI?t=1m57s

SimCity 2000? (3, Insightful)

VorpalRodent (964940) | about 3 months ago | (#46842411)

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

Re:SimCity 2000? (0)

Anonymous Coward | about 3 months ago | (#46843113)

Just turn off disasters. Then there's no downside to this technology!

Re:SimCity 2000? (0)

Anonymous Coward | about 3 months ago | (#46843225)

Bah, even without disasters the plant will decay after 50 years, just like everything else.

Except hydroelectric. We need a mountain, a mountain made entirely of waterfalls!

no where left to hide may as well stay here.. (0)

Anonymous Coward | about 3 months ago | (#46842459)

& recover our spirit of honor & compassion.. the healing begins as soon as the bleeding stops (ama). little miss dna cannot be wrong.. history is racing up to correct itself & us.. what a gig.. thanks moms

Corn fields? (5, Funny)

Hamsterdan (815291) | about 3 months ago | (#46842481)

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

Re:Corn fields? (0)

Anonymous Coward | about 3 months ago | (#46842769)

Mmmmmmmmm popcorn tsunami...

How Japan Plans To Build ... (1)

jeff13 (255285) | about 3 months ago | (#46842523)

How Japan Plans To Build Orbital Solar Power Stations?

With giant freakin' robots! Obviously.

They should put it at L5 (4, Funny)

karlandtanya (601084) | about 3 months ago | (#46842539)

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!

Energy and materials cost (1)

WillAffleckUW (858324) | about 3 months ago | (#46842609)

The problem is that solar is really cheap.

Really really cheap.

Back when we founded the Solar Energy Society of Canada in the 70s, it was really really expensive.

Now it's cheaper than oil and competitive (if you removed the artificial cheap land leases and tax subsidies for coal) with coal.

So, getting a solar array up into space takes a lot of energy and resources per solar panel (even if film). Transmission also has a cost, and you have to build ground-based receivers - if they miss (drift) it becomes a nightmare.

The same total cost of materials and energy would be better used turning radioactive lands in Japan that nobody will live in, farm on, or work in, into solar panel grids placed over grazing land for experimental animal hybrids, quite frankly.

Not unless we have a space elevator (1)

wisebabo (638845) | about 3 months ago | (#46842617)

I'm afraid that even if Space X comes to the rescue and gives us a 2-order magnitude (factor of 100) reduction in launch costs it still doesn't make economic sense. As other posters have mentioned, why not just put it on earth? The relative lack of efficiency is more than made up for by not having to pay $$$ per kg to get it into geo-sync orbit. (However a great many cool, exciting and useful things like semi-affordable trips to space for the semi-rich and really good planetary exploration will become possible with a 2-order magnitude reduction in launch costs so let's hope that Space X can give us fully reusable launch systems!).

No, the only way this makes economic sense is if we have a space elevator (or cheap, lightweight nuclear fusion engines*, or anti-gravity, or giant swans pulling us in winged chariots to the heavens). Now there may be other applications (military? propulsion system for interstellar vehicles?) for having a large power station in geo-sync orbit but many of them don't make sense either (a simple bucket of sand at orbital velocities could do major damage to it).

*but if we have nuclear fusion, why would we need solar?

Solar-pumped laser(s) instead of microwaves? (1)

kheldan (1460303) | about 3 months ago | (#46842741)

How feasible/practical would this be? What would the efficiency be compared to converting sunlight to electricity, then to microwaves at high power (MW? GW? TW?) then having to 'receive' those and convert them to DC power?

Why not in stratosphere ? (0)

Anonymous Coward | about 3 months ago | (#46842775)

Stratosphere is far easier and cheaper to get to, it is above clouds, and down path is way shorter. Let's try to do that in the stratosphere !

its always sunny somewhere (1)

roubles (716740) | about 3 months ago | (#46842799)

If the goal is just to collect sunlight 24 hours a day, you could just build solar power stations across the globe. It would be a heckuva lot cheaper than building one in space. But maybe that makes too much sense.

Another thought that comes to mind is that the loss in power during wireless transfer would be significant. I'd love to see the calculations that show that this is more practical than collecting the energy on different locations on the surface of the earth.

Lastly, with all this talk of "supposed" global warming, I don't think we are going to do ourselves any favors by pointing concentrated microwave beams at earth ;-)

Parabolic mirrors directed to a ground station (0)

Anonymous Coward | about 3 months ago | (#46842845)

Why not bend light around the earth via some strategically placed orbital mirrors?

It would be like Satellite TV, in reverse.

Profit (0)

Anonymous Coward | about 3 months ago | (#46843449)

1. Solar powerplant in space
2. Generate antimatter by the spoon full
3. ...
4. Profit!?!

Imagine... (1)

Elledan (582730) | about 3 months ago | (#46843659)

Just imagine the massive nuclear power (fission and fusion) infrastructure (including reprocessing) one could construct for the cost of this project. No matter how one looks at it, this kind of space-based PV only gets attention because it seems so cool. In the end we can get a more reliable power infrastructure for less money simply by investing in what is a proven and known to be safe (though not idiot-proof, sadly) technology.

But hey, space. I'm sure it's far more cool and less controversial :)
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