Energetica India 89 - May 2020

36 energetica INDIA- May_2020 The environment aspect refers to the ecological impact of these products upon disposal. Both PV modules and batter- ies contain metals as an active component. In PV modules, two different technologies are prevalent- crystalline silicon and thin-film. The major components of a crystalline silicon module are silicon, aluminium, copper, and silver. The thin-film mod - ules contain compounds of tin, cadmium, and lead, besides aluminium, copper and silver. In parallel, the battery sector is dominated by different chemistries of lithium-ion technolo- gy,the main metallic components of which are lithium, man- ganese, nickel, iron, and cobalt. They also containa solution of metals as electrolytes such aslithium hexafluorophosphate (LiPF6). Each of these metals has distinct environmental impact, entail- ing specific handling and disposal procedures.While alumin - ium and silicon are relatively less toxic, the heavy ones such as cadmium, tin, and lead are an environmental hazard. In addition to these visible metallic parts, some bulk components such as module glass are threats to the environment. Glass in PV modules contains antimony to improve the module’s stability under light irradiation. Antimony is a potent human carcinogenic. Intuitively, none of these damaged products should be dumped directly into the environment or sent for secondary consumption without proper treatment. However, this is the prevalent practice that leads to the second issue of resource management. As metals are vital for PV modules and batteries, they should be used efficiently.Some of them have limited reserves and are also used competitively in other industries. Researchers at the Council on Energy, Environment and Water (CEEW) have conducted an assessment on the criticality of different metals for Indian manufacturing industry (Gupta, Biswas and Gane- san 2016). The analysis identifies silicon, germanium, lithium, and cobalt as critical minerals, based on their economic im- portance in the renewables sector and the risk associated with their geographical reserves. Further, metals such as cobalt, nickel, and iron have relatively low supply risk,butare exten- sively used in other industries such as chemicals, aerospace, and electronics. Thecompetitive consumption of these metals in other industries coupled with limited availability and geo- political uncertainty in the supply chain can increase the cost of the end products. A PV module represents almost 50% of the overall cost of solar PV systems. Batteries, on the other hand, represent almost 70% of the total cost of two-wheeler electric vehicles and 50% of four-wheelers. The cost trajectory of these technologies will be driven by the availability of these critical minerals and their replacement by alternative materials or technologies. While the latter might take time, the supply SOLAR POWER