PV Gap

Lucy Said:

i have questions about the energy, SOLAR POWER?

We Answered:

Solar cells consist of two semiconductors stuck together.

Silicon has 4 outer electrons so forms 4 bonds. If you put a tiny bit of something with 3 outer electrons in one block of Si, then that will be missing a bond.

If you put a tiny bit of something with 5 outer electrons in another block of Si then that will form 4 bonds and it turns out the thermal energy at room temperature is enough to 'exite' the spare electron into the conduction band so it can move around.

You bring the two blocks into contact and the excited electrons flow from one block to the other. Remember the first one had some stuff with only 3 outer electrons in? Well, it wants to fit in with teh rest of the Si, so it needs 4 electrons. That's where those spare ones go.

You've taken electrons from one block and put it in the other - you've moved charge, which creates a voltage/electric field.

If you shine light on the semiconductor, the light is absorbed by electrons which use the energy to get up into the conduction band. Now that you have an electric field, this will push them in one direction. Electrons moving in one direction is a current!

That's how you convert light to electricity.

It's hard to explain without quantum physics though, it's an entirely quantum process.




Advantages/benefits: doesn't require fuel. Silent. Can be put up almost anywhere (eg on top of a roof...), good in areas where there isn't a grid connection.

In the longer term prices will come down and it'll be an idea technology.

Erin Said:

Solar Power/Energy Question?

We Answered:

The world as you know has many various regions each with its own climate, elevation, and people.

The best war for the energy crisis to be solved is definitely renewable energy.
Solar energy should be used in deserts, coastal regions, and other places with lots of sunlight.
Hydro electric should be used in places with flowing, forceful water that WILL NOT impede migratory fish like Salmon and others.
Geothermal is good in places like Iceland that are very close to the lower layers of the earth's crust or sea floor.
Wind energy should be used in places, obviously, with lots of wind like coasts and flat lands such as Kansas.

In my opinion, Biofuels are not good for long term sustainability. The impact it has on food production and subsequent rainforest destruction to increase that food production(corn and other plants) is not worth the benefits they may present.

The best solution for the worldwide energy crisis is to use combinations of these sources, to keep from be overreliant on any one source. Although some of these sources are quite expensive, solar for example, with increased use, they will be developed to be more efficient and less expensive.