Solar Panels Question

[blueg33]

If everyone had solar panels would it make the world darker or colder, or both?

Discuss

[Happy82]

Both because we'd have no energy to light or heat homes.

[scubadude]

Happy82 said:

Both because we'd have no energy to light or heat homes.

ROFLAC

Brilliant, thankyou- I needed that Happy, just spat my lunch over my keyboard.

[annodomini2]

Neither.

Most of the light is either:

1. Absorbed as heat
2. Reflected back into space.

We are just converting some of it into electricity to be converted into heat somewhere else.

[Steven Quas]

It will make the World slightly colder assuming the panels are more reflective than whatever they shade. You could get the same effect with using mirrors instead of solar panels...

Steven Quas

Hamburg

[MartG]

If the panels absorb more solar energy ( inluding visible, IR, and UV ) than the existing surface they are placed on then the net effect will be to add energy to the Earth's ecosystem. Conversely if they are less absorbant then they will tend to cool it.

Of course it is made more complex by the fact that surfaces absorb energy in one wavelength and re-radiate it in another e.g. dark surfaces absorbing visible light and re-radiating it as IR ( i.e. heat ) which is retained by the atmosphere.

I'm surprised though that none of the global warmists have advocated everyone painting their house roof white to reflect solar energy back out into space - I guess they'd rather just tax us instead

[Seeker UK]

MartG said:

If the panels absorb more solar energy ( inluding visible, IR, and UV ) than the existing surface they are placed on then the net effect will be to add energy to the Earth's ecosystem. Conversely if they are less absorbant then they will tend to cool it.

Of course it is made more complex by the fact that surfaces absorb energy in one wavelength and re-radiate it in another e.g. dark surfaces absorbing visible light and re-radiating it as IR ( i.e. heat ) which is retained by the atmosphere.

I'm surprised though that none of the global warmists have advocated everyone painting their house roof white to reflect solar energy back out into space - I guess they'd rather just tax us instead

But, the electricity generated would be used generating some heat. Effectively, you're delaying the heating effect.

[MartG]

Seeker UK said:

But, the electricity generated would be used generating some heat. Effectively, you're delaying the heating effect.

The electricity is only ( a small ) part of the total light energy absorbed by a panel - most of it is re-radiated immediately as heat.

You could also argue that if the electricity was used to power an LED spotlight ( high efficiency, not much energy wasted as heat ) pointing upwards, then very little of the energy converted to electricity would be retained within the earth's ecosystem, with most of it escaping as light into space

[hairykrishna]

MartG said:

I'm surprised though that none of the global warmists have advocated everyone painting their house roof white to reflect solar energy back out into space - I guess they'd rather just tax us instead

Lots of discussion of it. Example; http://link.springer.com/article/10.1007/s11027-00...

[Nimby]

FWIW I pointed my IR thermometer first at our PV panels and then at the concrete roof-tiles bordering them and there was no temperature difference (to 0.1C). So presumably they were each absorbing and re-radiating about the same amount of energy - at IR wavelengths anyway.