Sunday, March 27, 2011

Random thought: Greenhouse effect and solar energy

Comparing the effects of greenhouse effect and solar energy. I was thinking and I came to an odd thought: is it hypocritical/counter-intuitive to use solar energy to combat greenhouse effect.

Primer: The greenhouse effect that some believe is contributing climate change. Light penetrates the glass and heats the interior of the greenhouse (heating the surfaces it touches upon), the heat is then radiated into the air. Rather than letting it pass through the heat is absorbed into the greenhouse gases and then re-radiated outwards, sometimes back into the surface. End result is that the greenhouse is warmer than expected. More of the sun's energy remains upon the Earth rather than being reflected/radiated back into space.

The basis for solar energy is capturing sunlight and converting it into electricity. I know of two methods that they do this. The first is through photovoltaicism (probably spelled that wrong), whereby photons are absorbed by a metal and a current is generated. This is what you see on lawn lights and calculators. The second I know heats up a medium and then converts the heat energy into electricity, in much the same way as conventional electricity generation. This method uses mirrors instead of panels, to focus, rather than collect, the sunlight onto one spot. This spot is usually inhabited by something with a high specific heat capacity. something like molten salts. This way the energy is stored long after the sun has gone down. The heat is then used in some sort of engine to drive a turbine or otherwise generate electricity.

Overly simplistic thought: Greenhouse gases (CO2, CH4, etc.) trap the sun's energy and convert it into heat. Solar power traps the sun's energy and converts it into heat, and then into electricity or directly into electricity. This electricity will likely be used and will, eventually produce heat. So Is using solar power contributing to the problem rather than helping it.

The other green power sources don't run into this problem. Wind, geothermal,and tidal utilize energy already absorbed by the planet. This energy comes from within the earth, from the movement of the earth, from the movement of the moon around the earth, and from the sun (only the energy that would have originally been absorbed by the earth)

So, is solar power adding to the problem rather than solving it?

Edit/Update:  Something I forgot to mention. A relatively recent solar power idea that I've read about is to beam energy collected from space down to earth. This would likely be done from a geostationary satellite that gathers the sun's rays and transmits them down to a receiver platform on earth via laser or microwave. This is, in many ways worse than conventional solar power with regards to this article as solar energy that would have normally passed the Earth by would then be transmitted to the planet.

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