# Caustic soda: Emissions

A power-hungry alkali whose footprint follows the grid

Source page: https://www.materialinsights.org/chemicals/caustic_soda/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 0.90 t CO2e per t range 0.66-1.5 · Europe 0.66 t CO2 per t (Euro Chlor 2022 eco-profile, updated Sep 2022); coal-heavy grids raise the global average Global emissions per year 81.0 Mt CO2e per year 2025 · 0.9 t x 90 Mt

Per t of caustic soda (100% basis), cradle-to-gate, mass allocation. Intensity: Euro Chlor 2022; global value indicative. Global total: derived (indicative).

#### Share of footprint by lifecycle phase
 Feedstock 5% Production / process 89% Movement 6%

#### Footprint by lifecycle phase

| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| **Feedstock** | about 0.05 t CO2e per t | 5% | salt production | salt 0.06 kg CO2e per kg (Euro Chlor 2013) | Euro Chlor eco-profile 2013 |
| **Production / process** | about 0.8 t CO2e per t | 89% | electricity for electrolysis and steam for evaporation | mostly indirect power emissions | Euro Chlor 2022 (indicative global) |
| **Movement** | about 0.05 t CO2e per t | 6% | ocean tankers and road tankers | long-haul exports raise this | indicative |
| **Use** | not applicable | – | neutralisation reactions | caustic can absorb CO2 (it is used in carbon capture scrubbing), but it is not a sink at scale | indicative |
| **End of life** | not applicable | – | caustic ends as dissolved sodium salts | alkaline effluent must be neutralised; red mud from alumina holds residual caustic | indicative |

#### Other environmental impacts

Alkaline effluents; red mud residue at alumina refineries; legacy mercury from mercury cells.

#### Levers to cut emissions

- Renewable electricity: cuts the footprint by up to about 90% (indicative)
- Oxygen-depolarised cathodes save about 25-30% of power (indicative)
- Mechanical vapour recompression for evaporation (indicative)
- Use co-product hydrogen as fuel

#### India

Indian caustic is made with coal-heavy grid or captive coal power; new capacity is often paired with renewable PPAs (DCM Shriram 2024).
 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 |
|---|---|---|---|---|
| **Membrane cells on round-the-clock renewable power** | about 0.1-0.2 t CO2e per t (indicative) | depends on firm power cost | Indian producers adding captive renewables, such as DCM Shriram's 44 MW (2024) | Indian Chemical News June 2024 |

 For a climate investor The decarbonisation opportunity is the same as for chlorine: firm, low-cost renewable power for a 6.4 Mt Indian industry, and energy-saving cell upgrades. Green caustic could find premium buyers in battery cathode precursors and export pulp, but no premium market is established yet.

## Other sections

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