PV Gap

Angela Said:

what are the different principles based on which electricity can be produced using SUNLIGHT(SOLAR ENERGY)?????

We Answered:

Photo-voltaic
Heat
Indirect via heat
Burning vegetation
Fossil fuels

Sunlight is white because it contains photons of a broad range (spectrum) of energies i.e. colours. So your question might be re-stated as "What are the different principles for solar energy suited to the different colours within sunlight?"

The obvious one is photo-voltaic cells that directly convert light into electricity. That covers the visible spectrum.

High-energy light, i.e. ultra-violet is best converted to electricity by using it to generate heat (infra-red) which then can be converted into electricity with the use of a turbine or Peltier effect heat pumps. The latter route can be directly used for infra-red, although most of it is stopped by our atmosphere.

Burning vegetation and fossil fuels (the latter derived from the former) are both ways of generating electricity from sunlight .. .they just take longer than the direct methods.. by 600million years in the case of petroleum.

Sylvia Said:

What are (if any) the negative effects of solar energy?

We Answered:

The only drawbacks are

(1) it's not really efficient yet--for most applications, the costs (resources) expended in constructing solar power devices are hard to recuperate in energy savings during the lifetime of the device.

(2) Batteries go hand-in-hand with solar power. (The sun doesn't shine all the time). Most battery technologies in use today involve nasty toxic chemicals.

Your fears about robbing the earth of sunlight are unfounded. Temperature would increase if we converted more of the sun's light to work (and then to heat) instead of letting it bounce away. Viewed in a very macroscopic way, agriculture is just solar power really. Plants convert sunlight to energy, which we use by eating or burning or whatever.