Why not spend $21 billion on solar power from space?

The Japanese government is prepared to spend some 2 trillion yen on a one-gigawatt orbiting solar power station—and this week Mitsubishi and other Japanese companies have signed on to boost the effort. Boasting some four kilometers of solar panels—maybe of the superefficient Spectrolab variety but more likely domestically sourced from Mitsubishi or Sharp—the space solar power station would orbit some 36,000 kilometers above Earth and transmit power via microwave or laser beam.

The benefit? Constant solar energy production as the space-based power plant never passes out of sunlight. The downsides? Only enough power for roughly 300,000 Japanese homes at a price tag of $21 billion, according to Japan's science ministry (about 127 million people live in Japan in some 47 million households, according to Wikipedia and the CIA's World Factbook). The Japan Aerospace Exploration Agency (JAXA) aims to have a system in space by 2030.

The first step will be launching a test satellite that will gather solar power and beam it back to Earth, probably in 2015. Already, ground tests show that some solar power (180 watts) can be beamed successfully.

Scientific American

Space based solar power system would have many problems that the Japanese will find out about when they try it.

One is the cost of getting the system into orbit and maintaining it.

Its one thing to build a solar system in the desert and if you have problems send a technicion in a truck out to fix it,
But the cost to send a person into geosynchronous orbit to do repairs is in the range of $5000 per pound.

Then there is the panels themselves. try taking a solar panel and shooting it with a .22 rifle.
There is a lot of debris and micrometeorites in space that will chew up space based systems. This means they have to use special panels that isolate damaged cells to keep the panels working that raises the cost by a factor of 500%
After a number of years the damage will become so bad you will have to replace the panels compleatly and that will increase the cost because you have to send the new panel into orbit plus remove the old panels and safely despose of them so that they will not cause damage to other satellites.
This will cost as much as putting the original satellites in orbit.

A space based system will cost a 100 times more then a ground based system. way more then using nuke power plants.

In 40 to 50 years if we have space habitats to build them and a moon base for raw materials solar power satellites will be cost effective

reply to post by ANNED


Damn, you need to put in a job application, since you know more about space than them :p

But i must agree, it's pretty much a PR stunt, but a needed one. Advancements will be made to current solar-cell technology, and there is a chance we can get stuff into orbit cheaper at that time than now.

Some points:
"spent" Solar cells will probably be pushed toward the earth to burn up in the atmosphere.
It would probably be very modular, making replacing "spent" cells "pretty easy"
The USA has lotsa space to put up some on-ground facilities, but japan has almost none - The nevada desert alone could probably fill all the needs, even with plug-in hybrids hitting the market yet i don't see much effort in it.

But IMO, windpower is better than solar. All the energy we consume eventually ends up in the atmosphere as heat, we might as well tap right back into that. And living in the windmill capital of the world i can safely say that they don't harm birds (The electromagnetic field is a huge warning lamp for them)

To me it seems like the next solar breakthrough is "just 5 years away"