For decades, scientists have explored the possibility of using space-based solar cells to power the Earth. Some see orbiting power stations as a clean and stable energy source that promises to slow global warming, while others dismiss the idea as an expensive and impractical solution to the world's energy problems. While the discussion goes on, researchers at the Japan Aerospace Exploration Agency (JAXA) have begun to develop the hardware.
JAXA, which plans to have a Space Solar Power System (SSPS) up and running by 2030, envisions a system consisting of giant solar collectors in geostationary orbit 36,000 kilometers above the Earth?s surface. The satellites convert sunlight into powerful microwave (or laser) beams that are aimed at receiving stations on Earth, where they are converted into electricity.
On February 20, JAXA will take a step closer to the goal when they begin testing a microwave power transmission system designed to beam the power from the satellites to Earth. In a series of experiments to be conducted at the Taiki Multi-Purpose Aerospace Park in Hokkaido, the researchers will use a 2.4-meter-diameter transmission antenna to send a microwave beam over 50 meters to a rectenna (rectifying antenna) that converts the microwave energy into electricity and powers a household heater. The researchers expect these initial tests to provide valuable engineering data that will pave the way for JAXA to build larger, more powerful systems.
JAXA says the orbiting solar arrays, which have the advantage of being able to collect energy around the clock regardless of the weather on the ground, will need to transmit microwaves through the earth's atmosphere at frequencies that are not affected by the weather. The researchers are now looking at using the 2.45GHz and 5.8GHz bands, which have been allocated for use with industrial, scientific and medical devices.
JAXA ultimately aims to build ground receiving stations that measure about 3 kilometers across and that can produce 1 gigawatt (1 million kilowatts) of electricity -- enough to power approximately 500,000 homes.
[Source: Hokkaido Shimbun]
Bondrake
Well, at least someone has been up on their SimCity technology progression. Just remember that putting these in crowded cities eventually leads to microwaves setting fire to your beautiful creations! :-P
[]ChrisNo
Wasn't this one of the short stories in Asimov's _I, Robot_?
[]Dave
Won't this microwave all the birds? Yum, fried chicken falling out of the sky.
[]jason
That's great! I wrote my first and only newspaper article on SPSS back in 1990. Peter Glaser, who I interviewed for the article, is one of the founders of the concept and I think has the patent. And Gerrard O'Neill did some important stuff. The biggest problem is the integrity of the unit in space. O'Neill said it should be made from material from the moon, to make it cost effective. Other cool issues too.
[]Robert
Ridiculous! There's ample solar power already hitting the earth's surface, it's just a question of harvesting it. In the USA a 100km x 100km area of desert can provide all the country's electricity using concentrating solar power (CSP),
Same for the Sahara - to provide power for the whole of the EU.
Utility-scale plants are being built in USA, Egypt, Australia, Algeria, Spain, India and China. As the oil price climbs, these plants will get more and more competitive, and investors will pile in. By the time Japan gets close to making their space system work, it will be obsolete. (even if it hasn't already been ditched because of safety concerns)
see http://www.trec-uk.org.uk and http://www.trecers.net for stuff that works. Unless you like just fantasising about things in space!
[]Matt Hughes
Um... 1 gigawatt? From geostationary orbit? The free space loss alone is -191dB, which means their satellite will have to be broadcasting at least 10^19 gigawatts of power!! That represents about 3*10^19 SQUARE KILOMETERS of solar arrays.
Has anyone told these guys that it's impossible?
[]Matt Hughes
Whoops, my error. I was assuming a pair of isotropic antennas. 5 to 10 square km would suffice, but still, that's too many.
[]Mark Allums
Matt Hughes:
Haven't you heard of MASERs?
Robert:
Satellites are greener than surface-based arrays. I expect the Sierra Club would object to surface solar in the desert.
[]Mark Allums
Yes, Robert, I did remember that the receiving antenna has to go somewhere too. Still a a bit eco-friendlier than desert arrays. And more flexible, too.
[]iriart
Maybe,I think it well be done.
[]Werner
This should provide power for longer, since the satellites still get sunlight after the ground gets dark.
[]Shoovi
...we're gonna to fry/die ;)
[]Yeh it's going to be nice weapon as someone above pointed out. Except this, how about worming up upper atmosphere layers huh?
qraal
A microwave SPS system can't be used as a weapon - you just can't get a tight enough power beam. Even a laser will suffer drastic defocussing over 36,000 km making its weapon potential pretty minimal too (that and the fact the lasing process wastes ~ 80% of their power as heat.)
The advantage over surface solar is there's no diurnal cycle, no atmospheric attenuation and no clouds. That means it's producing up to 12 times more energy per annum than ground-based systems, even with sun-trackers, depending on your latitude.
And in case you didn't get it the first time Solar Power Satellites are GREEN - more so than ground-based solar. Both use nasty toxic chemicals to make PVs - BUT SPS uses less PVs and thus less nasty toxic chemicals.
[]Sebastian
me parece impresionante pero creo que se puede utilizar como arma o estoy equivocado.
[]T.Pott
Sebastian:
[]Es Verdad!
ISS Alum
The US National Security Space Office published a report last year:
http://spacesolarpower.files.wordpress.com/2007/11/final-sbsp-interim-assessment-release-01.pdf
Anyone seriously interested should read this before forming too many opinions about space solar power.
Two points:
[]- JAXA is doing the kind of research needed to prove the economic viability of space solar power
- microwave power beams are designed to be worthless for weapons and have minimal environmental impacts for a simple reason - such effects would reduce power transmission efficiency
Jeff
In the end as all the countries install their own SSP systems and eventually double the concentration on light that would normally strike the earth, how green would this be?
Seems like the earth would eventually be brown and burnt after all.
Using the light that strkes the earth would seem to be the best idea but if the sun ever has a substantial drop in output I suppose this could be a benifit.
[]Mo
As pointed out by some about microwave exposure to human and animals within its cone. As suggested it would be like microwaving life on the surface with its attendent damage, like eye cataracs, tissue damage, cancer, etc. etc. This insanity...it must be caused by eating whale meat procured illegally.
[]bacullen
all the theoretical work was done in the 70's. conversion efficiencies in the 65% range AFTER the PV cells. Looked marginal then probably still marginal for uS or EU but Japan may be another story.
[]Rhinoxwind
Although it sounds ridiculous but i think it is worth to try as Japan already has artificial island. Land probebly is not a problem in US or China. Some countries has little land but high energy consumption, it is a pretty good technology for them. Unless the big size countries give their land for free to make a better world.
[]Rhinoxwind
Forgot to raise a question if someone could answer me, i know this question is a bit stupid.
If it is days in the periodic meteror shower, Will the solar panel in the space get damage as I assume it has a pretty large surface area or it has some other laser beam ti shot the meteror down?
[]kb5tlq
to those of you that feel that the toxic input-ouput of this effort would further damage the eco-system, I MIGHT point out that gasoline WAS once concidered a WASTE product of lamp oil production? have you looked at how (and of what) the dashboards of your own cars are MADE?
Yes, SAT based transmission would be inefficient as that PV's are at present approx. 10% efficient in the conversion, But they would have about 200,000 billion acres in which they could play!
ground based systems could easily be maintained AND secured while being cross connected to minimize outages caused by maniacs with guns, bombs, etc.
AND, they could be used by the normal human being, AKA you and I.
think of this,
you have you TV and DVD set-up in you Yurt, Tee-Pee, or the basic cave. how can (with the advent of satellites) anyone be
controlled by their gov.'s or the ones who want to be
their masters (AL-QIADA and others) if they have access to power and info at their command?
Yes, this will be an Apollo level effort, but look at what was gained for all of mankind for the puny amount that was spent then, as compared to what is being spent per diem for 1 person to go 1000 km around the "civilized countries" by automobile today?
[]richard schumacher
Not necessarily PV; Solar thermal can be about 40% efficient. Yes, impacts will cause steady degradation, so it will require periodic maintenance and repair. Nothing's perfect.
[]andrew
There are telephone poles and street light poles in almost every city. It would be a simple thing to equip all of them with wind turbines. I'm talking about the smaller egg beater shaped type. Every building should have pvc's and wind turbines also. Voila. 66% of all the power we need with no green house gasses. Need more power? No problem. People are unemplopyed all over the world. Pay them to run on treadmills and peddle bicycles conected to generators. This results in no unemployment, a healthier population and lower health care costs. tadaa. Problem solved.
[]dextercath96
Thank you for this reliable information about solar power. I would like to develop alternative energy like solar power generator. I am happy that Japan is developing this kind of solar power equipment. Read http://www.sunpowerport.com. Can I know our ideas about it? Thank you.
[]seba
check this video about SSPS by JAXA http://www.youtube.com/watch?v=D56vRfv71OA
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