Polycrystalline Silicon — Polycrystalline
Hardware Components
Polycrystalline, or Poly-Si, is a type of silicon solar panel made from molten silicon cooled rapidly so that it forms many small crystals (multi-crystalline) within a single cell [IEC 61215]. Typical module efficiency is 15-17%, lower than monocrystalline because the inter-crystal boundaries impede electron flow [ITRPV 2024].
The simpler casting production process made polycrystalline manufacturing cost historically 5-10% lower than monocrystalline. This cost difference was its main attraction from the 2000s through the mid-2010s.
However, the market trend of 2018-2026 reversed this dynamic. The efficiency of monocrystalline PERC rose significantly while its production cost fell drastically — narrowing the price gap to the point of no longer being economically significant. As a result, polycrystalline's global market share fell from around 30% in 2018 to below 5% in 2024, displaced by monocrystalline and TOPCon as the mainstream [ITRPV 2024].
Practical implication for Indonesian rooftop installations: an efficiency of 15-17% means polycrystalline requires a larger roof area for the same kWp capacity than monocrystalline (efficiency 19-23%). For a limited roof, this area difference becomes a more crucial deciding factor in technology selection than a mere price-per-watt comparison [IRENA, Renewable Power Generation Costs, 2023].
Indonesian PLTS Application Example
For a 5 kWp PLTS system in Surabaya (PSH 4.9 kWh/m²/day [NASA POWER 1984-2023]), 15%-efficiency polycrystalline panels require a module area of about 33 m², whereas 21%-efficiency monocrystalline requires only about 24 m² — a 9 m² difference for identical capacity. In the field, this difference is often the reason a factory facility manager switches to monocrystalline even when the price per watt is similar.
Sources & References
- International Technology Roadmap for Photovoltaic (ITRPV), ITRPV 15th Edition 2024, VDMA Photovoltaic Equipment (2024)
- IRENA, Renewable Power Generation Costs in 2023, International Renewable Energy Agency, 2024 (2024)
- IEC 61215, Crystalline silicon terrestrial photovoltaic (PV) modules — Design qualification and type approval, latest edition
- NASA POWER LARC, Surface meteorology and Solar Energy data set, climatology 1984-2023 (1984-2023)
See Also
Monocrystalline
(Monocrystalline Silicon (Single-Crystal Silicon))Monocrystalline, or Mono-Si, is a type of solar panel made from a single-crystal silicon ingot — one continuous crystal structure with no grain boundaries. The efficiency of monocrystalline modules is currently in the 19-23% range, with premium cells reaching 24-26% [ITRPV 2024].
TOPCon
(Tunnel Oxide Passivated Contact)TOPCon is a silicon solar cell architecture that adds a tunnel oxide layer and a thin polycrystalline silicon layer on the rear side of the cell to suppress charge-carrier recombination. Commercial TOPCon module efficiency reaches 22-24%, with laboratory cell records exceeding 25% [ITRPV, International Technology Roadmap for Photovoltaic, 2024 edition].
Derating Factor
The derating factor is a reduction factor that makes a solar PV (PLTS) system's actual output lower than its nominal STC capacity. Derating covers cell-temperature losses, surface soiling, module mismatch, DC and AC cabling, and inverter efficiency. For Indonesia's tropical climate, the combined derating is usually in the 80-85% range.