Tuesday, June 14, 2011

Amorphous Silicon Solar Cells

The efficiency of amorphous solar cells is typically between 6 and 8%. The Lifetime of amorphous cells is shorter than the lifetime of crystalline cells. Amorphous cells have current density of up to 15 mA/cm2, and the voltage of the cell without connected load of 0.8 V, which is more compared to crystalline cells. Their spectral response reaches maximum at the wavelengths of blue light therefore, the ideal light source for amorphous solar cells is fluorescent lamp.

Crystalline Silicon Solar Cells

Among all kinds of solar cells we describe silicon solar cells only, for they are the most widely used. Their efficiency is limited due to several factors. The energy of photons decreases at higher wavelengths. The highest wavelength when the energy of photon is still big enough to produce free electrons is 1.15 μm (valid for silicon only). Radiation with higher wavelength causes only heating up of solar cell and does not produce any electrical current. Each photon can cause only production of one electron-hole pair. So even at lower wavelengths many photons do not produce any electron-hole pairs, yet they effect on increasing solar cell temperature. The highest efficiency of silicon solar cell is around 23 %, by some other semi-conductor materials up to 30 %, which is dependent on wavelength and semiconductor material. Self loses are caused by metal contacts on the upper side of a solar cell, solar cell resistance and due to solar radiation reflectance on the upper side (glass) of a solar cell. Crystalline solar cells are usually wafers, about 0.3 mm thick, sawn from Si ingot with diameter of 10 to 15 cm. They generate approximately 35 mA of current per cm2 area (together up to 2 A/cell) at voltage of 550 mV at full illumination. Lab solar cells have the efficiency of up to 20 %, and classically produced solar cells up to 15 %.

Solar Cells

Solar cells are in fact large area semiconductor diodes. Due to photo voltaic effect energy of light (energy of photons) converts into electrical current. At p-n junction, an electric field is built up which leads to the separation of the charge carriers (electrons and holes). At incidence of photon stream onto semiconductor material the electrons are released, if the energy of photons is sufficient. Contact to a solar cell is realized due to metal contacts. If the circuit is closed, meaning an electrical load is connected, then direct current flows. The energy of photons comes in "packages" which are called quants. The energy of each quantum depends on the wavelength of the visible light or electromagnetic waves. The electrons are released, however, the electric current flows only if the energy of each quantum is greater than WL - WV (boundaries of valence and conductive bands).

Saturday, April 16, 2011

GreenPower options

Origin GreenPower is generated predominately from solar, wind and biomass sources. All of our GreenPower products meet the stringent accreditation rules of the Government's GreenPower program.
How does it work?

When you purchase one of our Government accredited GreenPower products, we'll have the chosen percentage of your electricity consumption matched into the electricity grid with electricity from GreenPower accredited renewable sources such as wind, solar, hydro and biomass.

Why solar electricity?

With an Origin solar electricity system, you'll:
Save money on your energy bills by generating your own clean electricity
Find it easy – your system comes fully installed and we'll organise everything from your paperwork to connection to the grid
Get a grid-connected solar energy system that best meets your needs
Enjoy competitive prices
Be helped by our team of dedicated solar energy specialists
Relax, knowing your solar panels come with a 25 year power output warranty
Enjoy peace of mind that your system will be installed by a BCSE grid-connect accredited installer, who will personally sign off on the installation report at the time of commissioning
Rest assured, knowing you're dealing with Australia's number one green energy provider.
Be rewarded with feed-in tariffs. If your solar system generates more power than you need, you have the potential to be reimbursed for any electricity your system feeds back into the grid, thanks to State Government feed-in tariffs (FITs). A feed-in tariff is a buy back rate paid on a net basis for any excess power your system produces that you don't first use in your home. Feed-in tariffs are designed to encourage more Australians to generate their own electricity and vary by state.

Solar energy for industry

INTRODUCTION
Sunlight is a clean, economical and safer alternate source to fossil fuel and batteries. It is a free and inexhaustible fuel source. It reduces electricity costs, as well as the number of batteries used into landfills. As it is environment friendly so many industries prefer solar energy as compared to fossil fuel.

Solar Power
Solar power has been used by industries for a long time but its demand increased in 1970 when the governments and industries were forced to use other sources of energy than oil. After research photovoltaic cells came into existed and solar energy took place of fossil fuel.

Solar energy platform in industries.
It is an open area of space with a large number of great big magnifying mirrors pointing towards the sun. These systems concentrate sun rays to a surface and heat the fluid that flows from one location to another through the common pipeline on which they are focused. This type of arrangement heats oil that is in the pipes which is then used to heat water to create steam. Oil is used because it can maintain heat and the steam obtained are used to drive the generators to get electricity.
Such an arrangement will be able to heat oil that is coming through pipes which will then be used to heat up water that will create steam. Oil is commonly employed as it can by character preserve the heat very well and at last the steam manufactured may be used to run generators to get electrical energy. Pressure which is involved in heating up the liquid can also be used to run many machines. The heat can increase the size of the fluid against the pistons of the motor which results in mechanical power. This power can be used to run generators which will then provide electricity.

Advantages of solar energy

• Reduced energy budget
As the energy is being used from a natural source it reduces the budget of a company.

• Reduced CO2 emissions
Solar source of energy is environment friendly there is no carbon emissions caused during the conversion of solar energy.

• Greater energy independence

• The solar energy is abundantly available on earth and it can be used for many years for the generation of energy.

• Solar power plants can be connected to the big existing present power sources to create a hybrid power system for energy formation in dry summer days.

• Solar power panels are long-lasting and do not need much repairs. Usually life time of solar power panels is up to 20 to 25 years, which give good reason for the initial cost of solar panel.

• Solar power supply systems are not at all noisy, they are soundless and efficient in their working hence protects pollution. ,.

• Solar panels are capable of linking with other type electric generators for e.g. gas turbines, wind, hydro etc. Batteries can also be charges for constant electricity supply.

• It will minimize amount of carbon-monoxide, greenhouse gasses and other pollution released into air. The more electricity from solar panels is used the more it is beneficial for environment to reduce pollution from our atmosphere.

Solar energy for industry

Industrial Solar Energy

Solar energy is the energy that comes from the sun. Every day the sun gives an enormous amount of energy to the earth. The sun emits amount of energy in one second more than ever used from the beginning of life on earth.

Solar Energy and Personal Empowerment

 Harnessing the Sun: How Solar Energy Empowers Individuals and Communities Solar energy isn't just about powering homes; it's about ...