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Author Topic: Could we capture more energy from the Sun?  (Read 4783 times)

Alan Blake

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Could we capture more energy from the Sun?
« on: 14/10/2009 11:30:03 »
Alan Blake  asked the Naked Scientists:
   
Hi Guys
 
I have a question related to the Earth's dwindling natural resources of energy...
 
I understand that when the Earth revolves around the Sun in its orbit it absorbs less than 1% of all the energy emanating from the Sun. So more than 99.9% of the Sun's energy - as far as the Earth is concerned - is "wasted".
 
Bearing in mind that the Sun is the ultimate source of all our energy sources then this is a great source of energy going to waste - which if harnessed could presumably supply all the Earth's energy needs.
 
Obviously we need to find cheap and easy ways of capturing and using the energy already received from the Sun - but why are we not also capturing more of the Sun's energy which is passing us by?
 
For instance - we are sending space craft up into orbit all the time circling the Earth - why cant we send up mirrors that could direct the suns rays to receptors on the Earth - or place many mirrors on the surface of the Moon which could trap the Sun's energy and redirect them to receptors on Earth.
 
Surely this "free" energy from the Sun which is currently wasted could be sufficient to solve the worlds dwindling gas and oil supplies - without any harmful effects?
 
Alan Blake 

What do you think?


 

Offline Freeman

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Could we capture more energy from the Sun?
« Reply #1 on: 14/10/2009 10:04:42 »
Alan Blake  asked the Naked Scientists:
   
Hi Guys
 
I have a question related to the Earth's dwindling natural resources of energy...
 
I understand that when the Earth revolves around the Sun in its orbit it absorbs less than 1% of all the energy emanating from the Sun. So more than 99.9% of the Sun's energy - as far as the Earth is concerned - is "wasted".
 
Bearing in mind that the Sun is the ultimate source of all our energy sources then this is a great source of energy going to waste - which if harnessed could presumably supply all the Earth's energy needs.
 
Obviously we need to find cheap and easy ways of capturing and using the energy already received from the Sun - but why are we not also capturing more of the Sun's energy which is passing us by?
 
For instance - we are sending space craft up into orbit all the time circling the Earth - why cant we send up mirrors that could direct the suns rays to receptors on the Earth - or place many mirrors on the surface of the Moon which could trap the Sun's energy and redirect them to receptors on Earth.
 
Surely this "free" energy from the Sun which is currently wasted could be sufficient to solve the worlds dwindling gas and oil supplies - without any harmful effects?
 
Alan Blake 

What do you think?

Greetings Alan.

Could you be talking about a system like this:

Space-based solar power (SBSP)
http://en.wikipedia.org/wiki/Space-based_solar_power [nofollow]

Good Reading. ;)
Cheers
Freeman
 

Offline teragram

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Could we capture more energy from the Sun?
« Reply #2 on: 15/10/2009 17:35:08 »
Why not use the "Space Elevator" as conceived by Yuri Artsutanov, Arthur C Clarke in "Fountains of Paradise", and others, to carry the energy back to earth via cables, rather than a microwave transmitter? Transmitters would need to be very carefully controlled directionally, and may produce a dangerous situation if control was lost.
 

Offline Freeman

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Could we capture more energy from the Sun?
« Reply #3 on: 15/10/2009 18:49:50 »
Why not use the "Space Elevator" as conceived by Yuri Artsutanov, Arthur C Clarke in "Fountains of Paradise", and others, to carry the energy back to earth via cables, rather than a microwave transmitter?

The biggest problem with that project is the cable itself.

Quote
Transmitters would need to be very carefully controlled directionally, and may produce a dangerous situation if control was lost.

I do not see the problem with that.As the distance is so great the microwave beam will not be highly focused.
Now in regard to the cable system.With all the space debris floating around out there traveling a tremendous speeds, if one piece were to hit the cable it will be problems [Understatement: HUGE].
 

Offline teragram

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Could we capture more energy from the Sun?
« Reply #4 on: 16/10/2009 16:27:22 »
I am aware that the "space elevator" is a rather far fetched idea, unlike others by Arthur C Clarke. To start with, the only way to achieve it is to start from a satellite in geostationary orbit and build a shaft from it toward the earth. But this would result in the centre of mass of the assembly migrating to a lower (non geostationary)orbit. therefore the structure must be extended at the same rate in the opposite direction, out into space. Clarke was, of course, aware of this. The finished item would be a 72,000kilometre assembly. How much energy and material would this project consume? However, I understand that leading authorities, including I think NASA are considering this idea. If it ever did come into being, why not use it to carry cables to earth? I realize that a 36,000Kilometre twin cable is quite a challenge from the transmission efficiency point of view, but is a microwave wave link better?
« Last Edit: 16/10/2009 16:30:05 by teragram »
 

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Could we capture more energy from the Sun?
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