**7. Future trends**

DWS has become the standard for mono-crystalline wafers, while it is expected to have a market share of >80% by 2022 for multi-crystalline wafers [2]. SWS for multi-crystalline wafers is expected to phase-out by that time. With DWS, the kerf loss would also become <80 μm by 2022, which would in turn reduce the poly-Si consumption per wafer below 15 g. 3BB design for front-contacts are expected to phase-out by 2020 with 50% share for 5BB design. With continuous improvements in Ag pastes and screens, the FS finger width is projected to reduce to 30 μm by 2022. Wet-chemical processing tools have crossed throughput of 8,000 wafers/h in 2018 and would touch 9,000 wafers/h by 2020. Thermal processing equipments have reached throughput of 5000 wafers/h in 2018 and expected to cross 7,000 wafers/h by 2020. The metallization and I-V testing/sorting section is expected to have a throughput of >7,000 wafers/h by 2022.

Al-BSF-based cell technology which has a market share of >60% in 2018 is expected to reduce to <20% by 2025. With more emphasis on high efficiency solar cells concepts, share of PERC technology is expected to be >50% by 2022. Production efficiency of Mono PERC is expected to be >22% by 2022, while for multi PERC it should touch 21% by the same time. An important aspect related to multi-PERC is the mitigation of LeTID-based problem to minimize the loss of efficiency after installations of the modules in the field. Si HJ cells with efficiencies of >22% in 2018 after expected to reach stable efficiency of 23% by 2020, with a market share of around 10% by 2022. High efficiency bifacial cells with an additional advantage of tapping the solar radiation from the rear-side is expected to have a market share of 20% by 2022. N-type back contact solar cells are expected to cross 24% efficiency by 2020.
