Solar Energy is about the future as well as the present. With unlimited potential, Solar Energy is a clean, efficient, and sustainable form of renewable energy. But Solar Energy is also a sound financial decision. With Solar panels powering your home, you\'ll see this every month when your electricity bill arrives. Finally, Solar Energy is a green decision - you\'ll feel good knowing that you will leave the world a greener, better place for your children.

Today, the worldwide demand for solar photovoltaic (PV) energy is greater than supply. It is one of the fastest growing forms of renewable energy. As manufacturing becomes more efficient, the cost of PV systems continues to drop. Prices have reduced 25 fold over the last 20 years.

Commercially, even electrical utilities are looking to Solar for a more stable cost structure. Research has shown that solar can even be effective in Northern climates. In California, electricity rates are increasing at a rate of 6.7% per year. Solar provides a hedge against future rate hikes. And in many countries, you can sell your surplus electricity back to the utility, generating a credit on your bill.

Not only is solar affordable, it is even more economical when you consider the alternative: the high costs of fossil fuel pollution and global warming. In recent opinion polls, solar energy scored higher than all other forms of energy when participants were asked what type of energy is best for future generations. Photovoltaic systems produce electric power with no carbon dioxide (CO2) emissions. The Carbon emission offset is calculated at approximately 7.5 tons of CO2 over the twenty-five year guaranteed life of one PV module

All in all, solar photovoltaic energy generation has a very bright future indeed.

 
About Photovoltaics

About Photovoltaics | Solar Energy | Typical System | Energy Production | Carbon Emissions

Anyone who has used a modern mathematical calculator can grasp the concept of photovoltaics (PV). It is simply the process of converting energy from the Sun into electricity that can power everything from household appliances and lights to commercial buildings and power plants.

In precisely the same way as the small solar cells on hand-held calculators eliminate the need for batteries, PV can provide the world with a clean, reliable source of electricity and reduce our reliance on ever-depleting fossil fuels.

The PV technology of the 21st century makes it possible. It employs layers of micro-fine crystalline silicon to convert ordinary sunlight into small electrical charges. This process is then multiplied thousands of times over to create, smaller than ever before, modules and systems that can generate enough electricity to power entire towns.

It\'s important to note that PV is different from the solar thermal energy used for heating or in hot water production. A single PV cell consists of two or more thin layers of semi-conducting material, most commonly crystalline silicon. When the silicon is exposed to light, small electrical charges are generated and conducted away by metal contacts as direct current (DC).

View an animated demonstration.

In order to maximize energy collection and conversion, single cells are connected together and housed in a module. These modules are the building blocks of the PV systems and are, in turn, connected together to generate usable volumes of electricity. In some instances, an inverter is also used to convert high voltage DC into lower voltage AC power.

Types of PV technologies

There are essentially two types of PV technology, crystalline and thin-film. Crystalline can again be broken down into two types:

• Monocrystalline Cells - These are made using cells cut from a single cylindrical crystal of silicon. While monocrystalline cells offer the highest efficiency (approximately 18% conversion of incident sunlight), their complex manufacturing process makes them slightly more expensive.
• Polycrystalline Cells - These are made by cutting micro-fine wafers from ingots of molten and recrystallized silicon. Polycrystalline cells are cheaper to produce, but there is a slight compromise on efficiency (approximately 14% conversion of incident sunlight).

Thin film PV is made by depositing an ultra thin layer of photovoltaic material onto a substrate. The most common type of thin-film PV is made from the material a-Si (amorphous silicon), but numerous other materials such as CIGS (copper indium/gallium diselenide) CIS (copper indium selenide), CdTe (Cadmium Teluride), dye-sensitized cells and organic solar cells are also possible.

Types of PV Systems

PV technology was first applied in space, by providing electricity to satellites. Today, PV systems can be used to power just about anything on Earth. PV systems operate in two basic forms.

Grid Connected PV Systems
These systems are connected to a broader electricity network. During the day, the solar electricity generated by the system is either used immediately or sold off to electricity supply companies. In the evening, when the system is unable to supply immediate power, electricity can be bought back from the network.

Off Grid PV Systems
These systems are used in isolation of electricity grids, and may be used to power radio repeater stations, telephone booths and street lighting. There is also a growing market for mobile PV in the boat and caravan leisure market. Off Grid (also known as Stand-Alone) PV systems also provide invaluable and affordable electricity in developing countries, where conventional electricity grids are unreliable or non-existent.