Solar Photovoltaic Technology

Two technologies that are currently used to harvest solar energy are the solar photovoltaic and solar thermal methods. Basically, solar photovoltaic technology (PV) involves the conversion of solar rays into electricity, which can then be fed into a grid or used separately to power lighting, heating and cooling systems as well as a wide range of appliances. Solar thermal technology, on the other hand, harnesses sunlight directly to produce solar power, which enables appliances such as solar cookers and water heaters to function without conventional electricity.

What is photovoltaic technology and how does it work? Solar PV technology uses arrays of solar cells to receive sunlight and convert the same into electricity. A solar cell is basically a fine silicon wafer. PV solar panels come in mono crystalline, poly crystalline, amorphous and thin – film varieties. Currently, crystalline silicon panels are the most commonly used PV systems. However, silicon is expensive and in short supply.

High production costs make silicon panels too expensive for the average consumer in India. Companies are researching alternatives such as thin film systems as well as other non – silicon options to bring down the cost of production and make PV solar panels widely accessible. Photovoltaic systems are developed using specific combinations of solar cells. Basically, PV systems are available in two designs, which are flat – plate and concentrator panels. As of now, all PV solar panels sold in India are constituted of crystalline silicon cells.

Solar shingles also use PV technology. These power generators are designed to look like regular roof shingles and the advantage is that they are quite often capable of providing power even when the roof is partially shaded.

PV Solar panels do not necessarily need direct sunlight, they can function in daylight. Hence, photovoltaic technology can produce some electricity even under cloudy conditions. A PV cell is made up of one or more layers of semi – conducting material, which is normally silicon. When the cells receive sunlight, an electric field develops across the layers resulting in a flow of electricity. The intensity or strength of PV cells is measured in terms of the energy they generate in maximum sunlight and is referred to as kilowatt peak or KWP.

PV systems connected to the grid require hardly any maintenance apart from ensuring that they are kept clean and are not in the shade from surrounding trees.

Photovoltaic technology can be used to power consumer appliances as well as large electrical systems in the commercial sector. Solar PV water pumping systems are used for irrigation and drinking water distribution. You can benefit from solar panels installed on your roof or wall so long as your house is not in the shadow of other buildings or large trees. Shade reduces the output of solar modules. Also, these panels can be heavy and the surface on which they are installed must be strong enough to support them.

This technology is more or less environmentally benign. Though the manufacturing process of PV panels is polluting to a certain extent, these panels are eco – friendly to use. Solar photovoltaic power does not emit greenhouse gases.

Thin – film technologies are being adopted by a few solar panel manufacturers because they use no polysilicon. Thin films cost less to produce than silicon cells as they are made up of wafer thin layers of photosensitive material and the manufacturing process consumes less energy. Thin films can be embedded in roof shingles, windows and sidings. Over the past two years or so, thin film production has increased almost four times, accounting for over 10% global market share.

Worldwide production of PV cells increased 51% in 2007. Globally, SunPower panels are reported to be the most efficient solar PV panels on the market. The other major global producers are Kyocera, Sharp and Q – Cells. With rising oil prices and growing awareness of the need to adopt environment friendly energy sources, the market for photovoltaic technology is poised for healthy growth.