ALL ABOUT SOLAR POWER ( but didn't know what to ask )

Photovoltaics (PV)
Photovoltaics are solid state semiconductor devices that convert light directly into electricity. A photovoltaic device (generally called a solar cell) consists of layers of semiconductor materials with different electronic properties. In a basic polycrystalline cell, the bulk of the material is silicon doped with a small amount quantity of boron to give it a positive or p-type character. A thin layer on the front of the cell is doped with with phosphorous to give it a negative on n-type character. The interface between these two layers contains an electric field and is called a junction.

Light consists of particles called photons. When light hits the solar cell, some of the photons are absorbed in the region of the junction, freeing electrons in the silicon crystal. If the photons have enough energy, the electrons will be able to overcome the electric field at the junction and are free to move through the silicon and into an external circuit. As they flow through the external circuit they give up their energy as useful work (turning motors, lighting lamps, recharging batteries, etc.) and return to the solar cell. A number of solar cells are usually arranged into a solar module to provide usable power in a handy package.

The PV process is completely solid state and self contained. There are no moving parts and no material is consumed or emitted.
(Source: Solarex (now BP Solar)


What does PV power cost?
Although this depends on the application, roughly the cost of PV is 100 times that of coal fired power production. This means that we don't have large numbers of solar power stations around the world. However when the infrastructure required for moving coal fired power to the location where its to be used, against the cost of having a solar power generator right there on the spot, solar power becomes a much more economic consideration. Initial purchase cost of approximately Aust$11.00 a Watt (2003 prices) to purchase one of the larger sized solar cell modules, has to be measured against the very long life term of the module (50 years is not unrealistic).

What about Cloudy weather?
Solar modules dramatically reduce power production in cloudy weather. Light overcast typically reduces power to 30%, and heavy overcast to 10% of normal rating. During these times, adequate batteries are required if continuous power supply is needed.
What about the environment?
Climatic change is a certainty when we release into the atmosphere carbon previously tied up in fossil deposits. The advantage of solar power is that once the solar module is produced, it keeps supplying electricity long after the embedded energy used in manufacture has been paid back. For rural areas, the long runs of cable required to transport mains power, as well as the transformers continuously running whether power is needed or not, means that as much as 50% of the power being produced is wasted.
What about Carbon Credits?
In Australia we have put together a scheme for creating carbon credits for users of solar power. Solarcom can assist with claiming these carbon credits as a rebate to help pay you for your decision to use solar. Typically we claim AUS $0.50 per installed Watt of BP Solar solar modules, which represents 5 years worth of solar power generation.