Large scale solar power - any negatives?

baldrick

Novice Member
I was just reading this story about plans to build massive solar farms in the North African deserts and it got me to thinking...

Today, the sun burns down on the desert land, heating the ground and this heat then radiates back into the air at night.

If you start to harvest this heat then the natural heating and warming cycle will cease, and I'm wondering if that could have some negative impact to the climate that makes the desert an obvious choice for a solar farm!?!?
 
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Solar

Well-known Member
Maybe, but solar panels don't harvest the heat, they use light.
 

baldrick

Novice Member
Maybe, but solar panels don't harvest the heat, they use light.
Photovoltaic type panels use light, but if you read the article you'll see that these farms are water based, with mirrors/panels focussing the sunlight onto pipes, super heating the water into steam to drive turbines...
 
Hmmm?

From now on, it seems to me we should ban all volcanoes from erupting.

Similarly, forest fires are utterly and totally forbidden too.
 
Hmmm?

From now on, it seems to me we should ban all volcanoes from erupting.

Similarly, forest fires are utterly and totally forbidden too.
 

baldrick

Novice Member
Hmmm?

From now on, it seems to me we should ban all volcanoes from erupting.

Similarly, forest fires are utterly and totally forbidden too.

Volcanoes and forest fires are natural and have been happening for millions of years. In fact, the only species they really impact is us because we don't like it when our houses get burnt to the ground! For all the rest it's just the normal cycle of things!

A desert has a surprisingly fragile eco-system that is derived from it's climate and I'm asking whether that climate could be altered by changing the fundamental properties of a desert?

All in all I have to mark your response as "sarcasm fail"!
 

Sparky83

Active Member
I'd have thought that regardless of the size of this array of solar panels that the shear size of the dessert would be so great that this wouldn't cause any issues.
 

DPinBucks

Distinguished Member
I'd have thought that regardless of the size of this array of solar panels that the shear size of the dessert would be so great that this wouldn't cause any issues.
Depends. Ice cream might be a problem unless you eat it quick.
 

baldrick

Novice Member
I'd have thought that regardless of the size of this array of solar panels that the shear size of the dessert would be so great that this wouldn't cause any issues.
Good point! I'm guessing one of these farms could cover hundreds if not thousands of acres so I wonder how large an area you need to impact before you could see changes?
 

ldoodle

Distinguished Member
Solar panels are fugly as hell. I wouldn't have them on my house even if they were istalled for free. I know this is not about home installation but I can't believe we're talking about runing landscapes!
 
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baldrick

Novice Member
Solar panels are fugly as hell. I wouldn't have them on my house even if they were istalled for free.

I guess if you can have them on an pitch of the roof that isn't really visible from the ground then they are a no brainer, especially as you can sell the power generated back to the power company for more than you buy it for...
 

ldoodle

Distinguished Member
I guess if you can have them on an pitch of the roof that isn't really visible from the ground then they are a no brainer, especially as you can sell the power generated back to the power company for more than you buy it for...

But they would be visible to me all the time. I'm surprised someone like Velux haven't invested in/created a solar power window panel, or some sort of roof tile.
 

John

Moderator
Solar panels are fugly as hell. I wouldn't have them on my house even if they were istalled for free. I know this is not about home installation but I can't believe we're talking about runing landscapes!

when was the last time you were in the Sahara ? . Not many out there to complain.
biggest problem would be the planet taking back what's hers
 

SBT

Banned
I guess if you can have them on an pitch of the roof that isn't really visible from the ground then they are a no brainer, especially as you can sell the power generated back to the power company for more than you buy it for...

A bungalow near me has just had them fitted.By the looks of the scaffolding i thought they was having a loft conversion, but these panels are massive,nearly the whole side of the roof is covered.I've only ever seen a roof with a few panels on but this looks really ugly.
 

Solar

Well-known Member
Photovoltaic type panels use light, but if you read the article you'll see that these farms are water based, with mirrors/panels focussing the sunlight onto pipes, super heating the water into steam to drive turbines...
I did read it, and the method they are using is concentrated light to directly heat the water and drive the turbines, which actually uses a very small amount of light compared to regular solar panels.

Just youtube "solar death ray" for an example of how efficient it is.
 

baldrick

Novice Member
I did read it, and the method they are using is concentrated light to directly heat the water and drive the turbines, which actually uses a very small amount of light compared to regular solar panels.

Just youtube "solar death ray" for an example of how efficient it is.

Agreed, but by capturing the light they will create a shadow on the ground and that ground will be cooler than if the sun had been shining on it.

The heat that has been extracted from the light will be piped away and converted to kinetic energy in the turbines so come sunset the ground will be considerable colder than it would have been before the farm was built and the heat that would normally have radiated back into the atmosphere will be doing good work as electricity powering my TV!
 

Sparky83

Active Member
baldrick said:
If you start to harvest this heat then the natural heating and warming cycle will cease, and I'm wondering if that could have some negative impact to the climate that makes the desert an obvious choice for a solar farm!?!?

If what your saying is correct and the heat isn't able to radiate back into the air at night, would this then slow down the process of global warming?

Like I said before tho, this would surely need to be on a massive scale to cause any problems.
 

DPinBucks

Distinguished Member
If what your saying is correct and the heat isn't able to radiate back into the air at night, would this then slow down the process of global warming?...
Actually, the opposite. If heat's prevented from radiating away, it will increase the rate of warming.

The fact is, all forms of energy capture will affect the environment.
  • Solar power will, as the OP suggests, disrupt the cooling/warming cycle of the area.
  • Tidal power will probably have the least impact, but even that will affect the ecosystems which depend upon a twice-daily gradual rise and fall;
  • Wave power will smooth out the sea surface in the 'shadow' of the power stations, and that will affect surface currents and land erosion;
  • Wind power will create areas of calm behind the turbines, with all sorts of potential effects on weather and possibly climate;
  • Nuclear power will release extra heat.
The point to remember, as I keep banging on about, is that climate is chaotic; sensitive to changing circumstances. So we don't really know what the effects will be, except that extra energy equates to increased disruption.

It's possible to argue that the amounts of energy we are taking out of the winds and waves is minuscule, and that's true up to a point. But the same arguments applied to coal in the 19th century and oil in the 20th. Growth will make for bigger and bigger capture stations, unless we start to realise that all these things except nuclear are simply expensive diversions, and give up on them except where local circumstances make them feasible.

There was a report published recently, I forget where, which stated that tide & wave power seem to be stalled in development, and that only wind is showing any signs of fulfilling its promise by the time the deadlines start to rear their heads in about 2050.
 

Solar

Well-known Member
[/LIST]The point to remember, as I keep banging on about, is that climate is chaotic; sensitive to changing circumstances. So we don't really know what the effects will be, except that extra energy equates to increased disruption.
I wouldn't have though so, the amount of energy we harvest will be on a microscopic scale compared to the amount radiating from the sun itself.
It would take a solar panel half the size of Africa to slightly disrupt the climate I would imagine.
 

DPinBucks

Distinguished Member
I wouldn't have though so, the amount of energy we harvest will be on a microscopic scale compared to the amount radiating from the sun itself.
It would take a solar panel half the size of Africa to slightly disrupt the climate I would imagine.
Well, as I say, we don't know for sure, but climate is chaotic, which means that it can be very sensitive to changing circumstances.

Another term is metastable, which means that it's stable within certain small boundaries, but give it a big enough nudge (which may in practice be very small), and it could shift unpredictably. The trouble is, we rarely know where those boundaries are; certainly not with weather or climate.
An example is a pencil standing on end. Push it very slightly and it will rock back upright. But very slightly more and it will fall, releasing quite a bit of energy.

Oh, and if past experience with the growth of coal and oil consumption is anything to go by, we may well up with panels which are half the size of Africa (OK, that's an exaggeration, but don't underestimate how big these things could get)
 
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