Polysilicon: Emissions

Why coal power makes polysilicon a carbon-heavy material

What this tab covers The greenhouse-gas footprint per tonne, split by lifecycle phase (feedstock, production, movement, use, end of life), the global total, other environmental impacts, levers and low-carbon routes, India's position, and where the investment opportunity lies. Emission intensity 35.0 t CO2e per t range about 10 (hydro-powered) to about 45 (coal-powered Siemens) · derived: Siemens about 48 kWh/kg x about 0.6 kg CO2/kWh (about 29 t) plus silicon metal at about 11 t CO2e/t x 1.1 t (about 12 t) and steam; FBR about 20-25 t; weighted 76/24 Global emissions per year 50.0 Mt CO2e per year 2025 · about 35 t x about 1.43 Mt

Per t of solar-grade polysilicon, cradle-to-gate. Intensity: China Polysilicon 2026 report (power use; 0.6 kg CO2 per kWh sensitivity); silicon tile; derived (indicative). Global total: derived (indicative).

Share of footprint by lifecycle phase

Feedstock 34% Production / process 63% Movement 3%

Footprint by lifecycle phase

Phase	Intensity	Share	Main sources of emissions	Notes	Source
Feedstock	about 12 t CO2e per t	34%	silicon metal from coal-fired arc furnaces (about 11 t CO2e per t Si)	4-5 t on Norwegian hydro (silicon tile)	silicon tile (derived, indicative)
Production / process	about 22 t CO2e per t	63%	electricity for deposition and hydrogenation (48-55 MWh/t Siemens, 11-20 FBR); steam	each 1 kWh/kg saved is about 0.6 kg CO2/kg	China Polysilicon 2026 report
Movement	about 1 t CO2e per t	3%	silicon metal and polysilicon transport within China and by sea	Indicative	Indicative
Use	not applicable	–	solar panels made from it avoid far more emissions over 25-30 years than their manufacture emits	Avoided emissions counted at the power system level	Not applicable
End of life	not published	–	module recycling recovers glass and aluminium; silicon recovery is small	Indicative	Indicative

Other environmental impacts

Chlorosilane and HCl safety; forced-labour concerns in Xinjiang (Conway 2023; US UFLPA); large water use (about 8 t per t for Siemens).

Levers to cut emissions

Switch Siemens to FBR (11-20 vs 48 kWh/kg)
Run plants on hydro, solar or wind power
Low-carbon silicon metal (hydro, charcoal reductants)
Reactor efficiency: leaders below 40 kWh/kg, ceiling about 35

India

India has no polysilicon output; new plants on coal-heavy Indian grid power would emit about 35-45 t CO2e per t unless paired with dedicated renewables (derived, indicative).

Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.

Low-carbon routes

Route	Intensity	Cost premium	Status	Source
FBR granular on clean power	about 15-20 t CO2e per t on grid; under 10 t on hydro (derived, indicative)	none; lowest cash cost (GCL RMB 25.31/kg)	GCL 480 kt; Tongwei 10 kt FBR pilot	China Polysilicon 2026 report; PV Tech (Apr 2025)
Hydro-powered Siemens (Wacker, Sichuan and Yunnan plants)	about 10-15 t CO2e per t (indicative)	higher in Europe; low in Chinese hydro provinces	Wacker Burghausen; Chinese plants in Leshan and Yunnan	Conway (2023); indicative

For a climate investor Polysilicon is India's largest missing link in solar manufacturing. The ALMM wafer mandate from June 2028 creates protected demand, and MNRE is preparing a PLI for more than 10 GW of polysilicon, though its size and terms were not public by October 2026. China has over 3.2 Mt of capacity running at about 40% and prices near RMB 32/kg in mid-2026, so an Indian plant only works with low-cost round-the-clock renewable power, FBR or best-in-class Siemens technology, and policy that holds for a decade. Clean power would also cut the footprint from about 35-45 t CO2e per t on the Indian grid to roughly 10-15 t, which may earn a premium in EU and US markets. Watch Adani (2028 target), Reliance (Jamnagar) and the PLI's final terms.