Thin film may lead the future PV market- but there are concerns on the life expectancy of these modules for 25 years.
Photovoltaics (also called ‘PV’) effect is the conversion of sunlight into electricity through a device known as the ‘Solar Cell.’ Semiconductor materials such as Silicon (Si) has a property to convert the direct sunlight in to electricity and hence most of module manufacturers use Crystaline Silicon cells to produce DC electricity. While Crystaline Silicon cells are having efficiency levels of around 14-18%, there are laboratory efforts underway to take this efficiency in the range of 22-23%. Very soon these cells will be available commercially. The currentl market share of Crystaline Silicon technology is about 85% of global PV cell market.
The cost of Silicon as semiconductor material is very high and contributes to about one third of the total module cost. In order to reduce the cost of PV modules, the thin film modules technology has got a good market presence in recent years. This technology utilizes only 1-2 μm of semiconductor absorber material, which is directly deposited on a supporting substrate such as glass, metal sheet or polymer. Amorphous silicon (a-Si) has historically been widely-used semiconductor for thin-film solar cells, while novel semiconductor structures like microcrystalline silicon (μc-Si), Cadmium Telluride (CdTe) and Copper Indium Gallium Selenide (CIGS), and their combinations are widely gaining popularity as thin-film alternatives. Thin film technology has a lower efficiency levels and it is in the range of 6-12%. there are efforts underway to increase the efficiency levels of thin film technology.
While most of Crystaline Silicon technologies have been tested for 25 year life time, there are still concerns over the life expectancy of thin film technology, there is no long-term performance data available for such technologies and hence there is a need within the market to develop confidence on the long-term performance of the thin film technology in Indian conditions.