Assume in the year 2100 the world uses 15-100x as much energy as we use now, but most of it is from renewable sources. Would these cause any ecological damage? Wouldn’t all the solar panels damage the environment by taking away energy from the sun, or would all the windmills change the wind paths on earth? Ted Sargent says the earth provides 10,000 more energy in sunlight than we need, but what happens when we are using 100-1000x more energy than we are using in 2006?
No cites, but it seems to me that the changes would largely be a wash.
For example, large amounts of solar panels would absorb the sunlight, and convert it into electricity.
So the ground below where those solar panels are placed would get less sunlight, and would not warm up as much as previously. The electricity generated by those panels is transmitted via wires into houses, where people use it to light the room and power the computer they use to read SDMB. Both the room lights and the computer are inefficient, converting much of the electricity into heat, which is released into the air.
Thus the net result is that the sunlight is converted into heat on the earth. It is moved a bit, but still on the earth’s surface. This would be largely irrelevant in terms of the net effect on the earth.
It seems to me that similar situations would apply to wind power, tidal power, etc.
Solar panels being some variation on black, you might instead get heat islands at facilities.
But is there any reason to think energy consumption will increase by that much?
Even factoring in developing nations using much more, and the world’s population growing, surely advancing technology is getting ever more efficient. Cars (regardless of their energy source) are getting lighter, incandescent light bulbs are being replaced by LEDs, aircraft are conveying larger numbers of passengers each, etc.
I don’t think so.
The heat island effect is caused by black areas (paved roadways, mostly) absorbing heat, and then radiating it back in the area. But black solar panels absorb the heat, and convert it into electricity. They don’t radiate it back into the area. (If they were 100% efficient, that is. In practice, they aren’t this efficient, and some percentage is radiated back into the area.)
It depends a lot on the source of renewable energy. The controversy over hydroelectric dams is pretty well-documented (here’s a sample search on Google). I’m really not aware of any concerns over widespread use of solar panels.
Solar panels seem generally to be deployed more frequently on rooftops than in open ground anyway.
There is some concern over wind turbines chopping up birds and that representing an ecological concern. I have seen evidence that they are really not such a big problem to birds and others that say they are. Of course if you dramatically increased the number of turbines producing power it would stand to reason it would become a bigger issue.
There is also a NIMBY issue with wind turbines as some people consider them an eyesore but that is not an ecological issue.
Ack! :smack: I’m an idiot… I completely forgot about materials used to make solar panels!
Most solar cells are made with materials including things like gallium arsenide and cadmium, which introduces issues of taking care of these materials through the processes of obtaining them, manufacturing the solar cell, and disposal once the solar cell is no longer useable.
How Solar Cells Work
Gallium Arsenide from Wikipedia
Cadmium from Wikipedia
As great as renewable energy is, there’s rarely a real-world choice that doesn’t have downsides as well.
Of course there are ecological consequences of renewable energy (TANSTAAFL). The question is how do those consequences compare to non-renewable sources. The question of what happens when we’re using orders of magnitude more energy than we use today is provocative - what is our goal, anyway? Are we “high per capita” consumers comfortable with the prospect of everyone on earth “achieving” our level of consumption?
How much energy consumption would it take to disrupt tidal patterns, or solar energy balance? Next time you’re in an airplane during the day, look out over the landscape and observe how vast the shimmering waves of heat are - if we somehow capture a large fraction of that and convert some of it into motion, much of it will still get wasted and returned to the atmosphere as, well, heat. If we can do that without spewing particulates into the atmosphere, we’ll be much better off than we are today.
But still, what is the point?