Solar Power Stations?

[flux_29]

A practical methord of getting engery (from the sun) -without creating nuclear/coal/oil stations - or just a pipe dream?

- That's both land based, and solar colectors positioned in space.

 

[jkladis]

Still ridiculously expensive. Last I read, the manufacturing of enough solar cells to charge electric cars (assuming all U.S. cars were suddenly electric) would be 22 trillion.

 

[Brent]

They aren't really THAT efficient yet for large scale use like that. That's really the problem with solar arrays right now, the efficiency and expense.

We've just now reached 40% efficiency - http://www.renewableenergyaccess.com/rea/news/story?id=46765

It use to be a lot lower, like 12%, so we have a long ways to go. Once we get in the 90%+ efficiencies maybe something like this would be doable.

 

[Ariadne]

Brent said:
They aren't really THAT efficient yet for large scale use like that. That's really the problem with solar arrays right now, the efficiency and expense.

We've just now reached 40% efficiency - http://www.renewableenergyaccess.com/rea/news/story?id=46765

It use to be a lot lower, like 12%, so we have a long ways to go. Once we get in the 90%+ efficiencies maybe something like this would be doable.

Because of the band-gap of silicon and the spectrum of black-body radiation emitted by the sun, we'll never get anywhere near 90%.

Most photo-voltaic cells are closer to 12%, because it's so much cheaper.

There are already a bunch of solar power plants in Germany, IIRC, which has lower insolation then much of the US.

 

[Bill Morris]

What about the Sahara?

 

[Brent]

Toresica said:

Brent said:
They aren't really THAT efficient yet for large scale use like that. That's really the problem with solar arrays right now, the efficiency and expense.

We've just now reached 40% efficiency - http://www.renewableenergyaccess.com/rea/news/story?id=46765

It use to be a lot lower, like 12%, so we have a long ways to go. Once we get in the 90%+ efficiencies maybe something like this would be doable.

Because of the band-gap of silicon and the spectrum of black-body radiation emitted by the sun, we'll never get anywhere near 90%.

Most photo-voltaic cells are closer to 12%, because it's so much cheaper.

There are already a bunch of solar power plants in Germany, IIRC, which has lower insolation then much of the US.

I dunno, never say never, I was watching a show about this and in it (it took place in the future) they had discovered the secret to reach I think 87%, it wasn't real of course, but just shows that in 20 years or whatever, who knows, maybe we will discover a way.

 

[Ariadne]

Brent said:
I dunno, never say never, I was watching a show about this and in it (it took place in the future) they had discovered the secret to reach I think 87%, it wasn't real of course, but just shows that in 20 years or whatever, who knows, maybe we will discover a way.

It's a law of physics - silicon cannot generate electricity from light with energy of less then its band-gap - 0.7 eV.

There's really nothing wrong with using lower efficiency PV cells, though - you just need more of them.

 

[Brent]

But what about using a different material

 

[Ariadne]

That's generally how they make the really efficient ones but it's really expensive.

 

[Brent]

Ah, perhaps in time it will become less expensive, or they might discover new materials that will make it more effecient.

 

[Ariadne]

Possible.

But we really don't need fancy schmancy III-IV materials for solar cells - having low efficiency cells is fine, you just need to cover more area.

Heck, most PV cells aren't the most efficient available anyway, and there are a few solar power stations already.

 

[26138]

LCARS 24 said:
What about the Sahara?

I believe that the equator receives the most sunlight year-round, or at least the most consistent sunlight day-to-day, so that would probably be the best spot for solar power plants.

 

[All Seeing Eye]

Would it be possible to build a huge solar collector in space full of solar panels facing the sun and then use the 'space tether' idea to beam the power back down to Earth via a huge cable? the cable will obviously be connected to a ground station and tethered to the Solar station in orbit, the reason why I mention the tether idea is because the idea to beam power down via microwaves has been said to be too dangerous, should the beam miss its target and hit a town or city its gunna be quite catastrophic.

 

[flux_29]

- Post Deleted -

 

[Brandonv]

The Pentagon is looking into space based solar.

http://hardware.slashdot.org/firehose.pl?id=329675&op=view

Toresica said:
That's generally how they make the really efficient ones but it's really expensive.

Yeah, I've read that the really efficient ones use rare earth metals, making them no good for large scale use.

 

[farmkid]

Maybe the answer is to use something other than photo-voltaic cells. Some time ago, I read about a solar energy device someone was developing. It turned solar energy into electricity, but without PV cells. It had a series of mirrors that focused the Sun's light on a central engine of some sort (I don't remember the name) that converted heat into kinetic energy. As I remember, the goal was to build the system such that it was a 4' X 6' X 1' box that could produce electricity for some low amount of money per kilowatt. They were pretty close when I read the article. I don't remember what the efficiency was, but I think it was similar or better than PV cells and the system was much cheaper to build.

 

[All Seeing Eye]

^ Sounds similar to the solar power stations that use mirrors to focus sunlight onto a central water tower, the water heats up and drives a turbine etc etc