# Solar energy questions
**URL:** https://boards.straightdope.com/t/solar-energy-questions/675061
**Category:** Factual Questions
**Created:** [November 29, 2013, 12:55pm UTC](https://boards.straightdope.com/t/solar-energy-questions/675061 "2013-11-29T12:55:19Z")
**Posts on this page:** 2
**Page:** 2
### Author:  [@Try2B\_Comprehensive](https://boards.straightdope.com/u/Try2B_Comprehensive)
#### Post date: [December 2, 2013, 4:36am UTC](https://boards.straightdope.com/t/solar-energy-questions/675061/21 "2013-12-02T04:36:31Z")
> [@WarmNPrickly](#):
>
> As I aid, it doesn’t matter if you put it on parking lots, rooftops or in one big spot in the desert. The material all needs to be made. It isn’t just about building infrastructure, it’s about the cost of raw materials. When everybody want’s lots of tellurium, indium and cadmium the price will skyrocket.
Cadmium and tellurium specifically are used in the manufacture of thin-film solar panels. As it turns out, those kinds of panels are currently cheaper to manufacture than silicon panels on a $ per watt basis. Trouble is that they are not very efficient (and they don’t last as long), and so they aren’t especially well-suited for rooftops or anyplace where space is limited. Plus, cadmium is a carcinogen and so thin films present a disposal problem. Still, with silicon panels you have copper and very small amounts of silver to worry about, among other things. But look around- out built environment is vast. We aren’t running out of what is required. Plus I think in the long run it makes more sense to use resources that generate power for 50 years and then get recycled instead of endlessly burning mountains of fuel.
> [@](#):
>
> Germany is an interesting example. They are making a good show for there efforts. I am curious as to how much power they are importing. I’d be all for that sort of effort in the US, but this effort is also heavily subsidized. It isn’t really solar power working because it is cost effective. It is solar power working because it is subsidized by the government. Good luck getting that here.
It is partly a myth that the solar industry runs on subsidies. Sure, Germany has credits and feed-in tariffs and so on, but at the same time those are in recognition of the fact that the costs of the current power generation regime aren’t properly accounted for. In California and the Southwest, in many locations solar panels produce power more cheaply than the utilities charge for it. The main issue is that solar generation requires an up-front investment. If big investors take on that risk, or if big companies lease the panels and handle the costs through long-term financing, there is money to be made right now. Luck isn’t really required. Where we’ll need luck is in preventing the right wing lunatic fringe from sabotaging the effort based on some conspiracy theory involving Socialism and government tyranny or some such nonsense.
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### Author:  [@kanicbird](https://boards.straightdope.com/u/kanicbird)
#### Post date: [December 2, 2013, 4:10pm UTC](https://boards.straightdope.com/t/solar-energy-questions/675061/22 "2013-12-02T16:10:22Z")
> [@Chronos](#):
>
> It’s not a matter of conversion to heat-- It’s already heat. There’s nothing special about infrared. A hot object can give off light of any wavelength, and light of any object, when absorbed by an object, will increase its temperature. The only reason we think of infrared specifically as heat is that that’s the dominant “color” emitted by objects at temperatures we’re familiar with, like warm-blooded animals or campfires. But for an object at about 6000 degrees, like the Sun, the light emitted (through exactly the same process) is mostly in the visible light range.
>
> So, ultimately, any sort of solar power scheme is a heat engine, with the Sun (at ~6000 degrees) as the hot reservoir, and the ambient environment on Earth (~300 degrees) as the cold reservoir. And thus, the maximum efficiency of any solar power scheme is the Carnot efficiency for those two temperatures.
Thanks, this makes sense, but the real thank you is the change in perspective this just gave me on how to view solar.
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