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Comment by sravfeyn | Hacker News Reader

This might be one of the most trivial questions, but I always tried to find the answer, failing always.

How is it that Solar energy is 'clean' and 'renewable', (or for that matter, any natural source of energy that plays a significant role on earth ecology), for if we make use of solar energy, will it not break the environmental equilibrium (temperatures, weather patterns etc) thereby making it 'unclean'? I see that using solar energy doesn't create any direct poisonous residue, but what about the unintended indirect effects? Did researchers already prove that there won'e be any effects or that the effects are far less significant than existing energy sources? (I would like to read actual research, apart from opinions/thoughts)

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Why would you think there's a possible break in environmental equilibrium due to solar energy. They amount of solar energy entering the atmosphere won't change. The only thing that changes is instead of the energy being wasted, it will be used to generate electricity. Conservation of energy guarantees this.

You asked for research, so here's a link from UCS. While they don't address that particular point, they do point out various potential problems. http://www.ucsusa.org/clean_energy/our-energy-choices/renewa...

> They amount of solar energy entering the atmosphere won't change

True

> The only thing that changes is instead of the energy being wasted

The solar energy that is falling on earth and that is not yet captured by the solar panels is doing a good number of direct things, such as Photosynthesis (not that Photosynthesis is stopped by putting solar panels, but one example of direct things Sun is doing), and an unknown number of indirect things such as Heating the atmosphere by scattering back from earthly-surface (causing many ecological reactions). Would you consider all these effects waste?

If we do know all these effects and also know that redirecting this solar energy into our energy needs won't significantly annihilate the effects, then it's good. I am curious to know about studies in this regard. If there are no studies and my question itself is pointless, I want to be enlightened, because I haven't had a satisfactory explanation yet.

One argument might be that, all the solar energy that's captured and used by us will also generate heat back into atmosphere and thereby not changing the ecological reactions in earth atmosphere - but I just made it up

You missed the point. He meant the energy you are talking about as 'wasted'.

All renewable energy sources that I can think of are processes that used to be (Energy -> Heat) and we turn them into (Energy -> Electricity -> Heat), where Energy is gravitational potential, EM radiation, etc.

The two changes are that the electricity is sometimes stored (so we have some small amount of energy cooped up in batteries instead of out in the world as heat) and that we often move the electricity before turning it into heat. The latter probably exacerbates the heat island effect, although I wouldn't expect it to be worse than pushing electricity from other sources into major cities. The former hardly seems like a problem given that global warming is a concern.

The amount of energy extracted, even if we were to go to all-solar, is a small fraction of the incident solar energy.

We used to say the same about CO2 emissions.

As long as a solar panel is lower albedo than the object it's installed on, the effects you're mentioning will be an improvement over the baseline effects of human development. If you start replacing fields with solar farms you may have to worry, but for a rooftop installation a solar panel will absorb more energy than the average tar or asphalt shingle roof surface.

Even on fields its not an issue (especially if you replace fields where sheep graze), as the sun still wanders around, and the animals can stand below the panels comfortably.

I've been waiting for that point to emerge, eventually used to denounce "clean renewables" by the same people now promoting them.

When scaled up to the hoped-for levels, we face the prospect of "solar strip-mining" whereby vast areas of land where sunlight used to reach ground is now blocked. How bad would it be?

Just to bracket the subject with a SWAG (corrections welcome): total USA electricity consumption is 534,938,184,000 watts. Practical maximum for solar is about 1,000 watts per square meter (a very optimistic collection & conversion rate). That works out to a minimum of 200 square miles (534 km^2) devoted entirely to solar collection, or 2,000 mi^2 for a more realistic solar efficiency. The upside is the latter is just 0.05% of total USA land area, hopefully with most of that being used on already-erected roofs.

What the climactic effect of 534,938,184,000 solar watts being converted into electricity instead of heat or photosynthesis is, I'll hope someone else figures out whilst I do lunch.

Nothing would happen?

Currently that amount of solar energy is converted into heat by reflection.

With solar, it would be converted into electricity, and later back into heat when used in a computer or for cooking.

The electricity always ends up as heat.

_Where_ is relevant. Point is every kilowatt of solar electricity you use is 1-10 m^2 of ground denied that energy. If the collector is on top of your house, fine - probably will help with your home cooling (gettin' hot here in GA), but over other space you've just deprived a nano-ecosystem its energy supply (no big deal for home use, but significant when it's upwards of a couple thousand square miles).

Well solar is still poisonous, but only during the manufacturing phase.

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