# Silicones: Emissions

Coal-powered silicon smelting dominates the footprint

Source page: https://www.materialinsights.org/chemicals/silicones/emissions/

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 7.50 t CO2e per t range about 4 (silicon on hydropower) to 10 (silicon on coal power) · derived: 0.44 t silicon x 11 + 0.95 t methanol x 1.8 = about 6.5 t, plus about 1.0 t for methyl chloride, direct process, hydrolysis and distillation, and transport Global emissions per year 24.0 Mt CO2e per year 2025 · about 3.25 Mt x 7.5 t CO2e/t (derived, indicative)

Per t of siloxane (DMC equivalent), cradle-to-gate. Intensity: silicon tile and methanol tile (indicative); derived. Global total: derived.

#### Share of footprint by lifecycle phase
 Feedstock 85% Production / process 13% Movement 1%

#### Footprint by lifecycle phase

| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| **Feedstock** | about 6.4 t CO2e/t | 85% | silicon smelting with carbon reductants and coal power in China; coal- or gas-based methanol | silicon alone about 4.8 t CO2e/t siloxane | derived from silicon and methanol tiles |
| **Production / process** | about 1.0 t CO2e/t | 13% | methyl chloride synthesis, direct process heat, distillation and hydrolysis | steam and power | indicative |
| **Movement** | about 0.1 t CO2e/t | 1% | container and tank shipping | small | indicative |
| **Use** | not applicable as emissions; use-phase savings often larger | – | durable; enables solar modules, insulation sealants, efficient electronics | industry LCAs claim use-phase savings exceed production emissions several-fold (indicative) | indicative |
| **End of life** | low CO2: combustion turns silicones mostly to silica, releasing about 1.2 t CO2 per t from methyl groups (calculated, indicative) | – | landfill, incineration | volatile siloxanes from personal care go to air and water; recycling to DMC is at pilot scale | calculated (indicative) |

#### Other environmental impacts

Persistent cyclic siloxanes (D4, D5, D6) in water and sediment; chlorosilane accident risk; silicon smelting air pollution.

#### Levers to cut emissions

- Silicon metal from hydropower or renewable power cuts the largest emission source (silicon tile: about 4-5 t CO2e/t Si on Norwegian hydro vs 11-15 t on Chinese coal).
- Bio-based or low-carbon methanol (biomethanol, e-methanol).
- Chemical recycling of silicone waste back to DMC (pilots by Elkem, Wacker and others; indicative).
- Biocarbon reductants in silicon furnaces (Elkem; indicative).

#### India

India's silicone footprint is embedded in imports from China. Rapid growth in solar module, EV and construction demand will raise India's silicone use; no domestic monomer plant was found in sources reached.
 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 |
|---|---|---|---|---|
| **Silicones from hydropower-based silicon (Norway, Canada, Brazil)** | about 4 t CO2e/t siloxane (derived, indicative) | not published | commercial (Elkem, Wacker supply chains; indicative) | derived from silicon tile |
| **Silicone recycling to DMC by depolymerisation** | not published | not published | pilot and early commercial in Europe and China (indicative) | indicative |

 For a climate investor Most silicone emissions come from making silicon metal, so cleaner silicones mean cleaner silicon: smelting on renewable power with biocarbon. For India, the near-term opening is downstream formulation for solar, EV and construction, where qualification creates margin; upstream monomer plants would face Chinese cost competition. What has to be true: secure low-carbon silicon supply and customers that pay for lower embodied emissions.

## Other sections

- [Summary](https://www.materialinsights.org/chemicals/silicones/index.md)
- [Overview](https://www.materialinsights.org/chemicals/silicones/overview/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/silicones/correlation/index.md)
- [Production route](https://www.materialinsights.org/chemicals/silicones/routes/index.md)
- [Production](https://www.materialinsights.org/chemicals/silicones/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/silicones/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/silicones/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/silicones/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/silicones/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/silicones/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/chemicals/silicones/characteristics/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/silicones/links/index.md)