Why solar panels manufacturing is costly?

Manufacturing of solar panels involves the following steps:

1) Quartz or silicon dioxide is heated up to 2000 degree Celsius to obtain metallurgical silicon ( purity of 99%) . Then high purity 99.999% pure Si is extracted through Siemens process. This process is energy intensive as well as have low yield per unit.

2) Ingot casting: Solar-grade or silicon material are melted in a crucible under controlled cooling. After sometime, the crystal–liquid interface moves upwards from the bottom of the crucible so as to obtain Si crystal ingot.

3)Wafer production: The peripheral section of ingots are cut to obtain cubic ingots which are wafered using multi wire saw machines. Wafers having thickness of 100 microns and dimensions of 10 x 10 cm2 to 15.6 x 15.6 cm2 are preferred. Approximately 30% of the silicon is wasted as saw dust kerf loss during this process. Wafer manufacturing makes up about 30% of the cost of solar cell.

4)Solar cell production: It involves selection of high quality wafers and doping them with impurities,followed by heating. Carefully metallic contacts are given on front and back sides.

5) PV module formation: Solar cells of similar characteristics are selected and soldered together. A polymer, Ethylene Vinyl Acetate(EVA) is pasted all over the soldered solar cell array to protect it from moisture. A sheet of transparent glass is placed over the front side of panel so as to protect it from dust and stones. Since the reflectivity of glass is high, an anti-reflective coating (TiO2 and Si1-xNx) is applied below the glass.The rear side of PV panel is covered with polyvinyl fluoride polymer commonly known as Tedlar to resist attack of chemicals, oils and stains. Then the module undergo different testing before being packed.

This is a general process layout for Crystalline Silicon solar cells. This process may be more complex than described. So manufacturing is costly as well as industry need huge initial investment.