Chlorine: Emissions

Coal grids double chlorine's carbon footprint

Coal grids double chlorine's carbon footprint 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 1.00 t CO2e per t range 0.7-1.6 · Europe 0.71 t CO2 per t (Euro Chlor 2022 eco-profile, updated Sep 2022); coal-heavy grids in China and India push the global average towards 1.0-1.6 Global emissions per year 80.0 Mt CO2e per year 2025 · 1.0 t x about 80 Mt chlorine; the whole ECU including caustic is about 160-170 Mt

Per t of chlorine, cradle-to-gate, mass allocation between chlorine, caustic soda and hydrogen. Intensity: Euro Chlor eco-profile 2022; global value indicative (basis: 2.7-3.0 MWh per t at 0.6-0.7 t CO2 per MWh, mass allocation 46% to chlorine). Global total: derived (indicative).

Share of footprint by lifecycle phase

Feedstock 5% Production / process 90% Movement 5%

Footprint by lifecycle phase

Phase	Intensity	Share	Main sources of emissions	Notes	Source
Feedstock	about 0.05 t CO2e per t	5%	salt mining and vacuum evaporation	salt about 0.06 kg CO2e per kg (Euro Chlor 2013 eco-profile) x 1.7 t, mass allocated	Euro Chlor eco-profile 2013
Production / process	about 0.9 t CO2e per t	90%	grid carbon intensity of the 2.5-2.8 MWh of electricity, plus steam for caustic	almost all indirect (scope 2)	Euro Chlor eco-profile 2022 (indicative global)
Movement	about 0.05 t CO2e per t	5%	short rail and road hauls	most chlorine moves by pipeline across the fence	indicative
Use	not applicable	–	chlorine is a reagent	disinfection by-products (trihalomethanes) in water are a health issue, not a climate one	WHO drinking water guidelines (indicative)
End of life	not applicable to chlorine itself	–	fate of PVC and chlorinated products	incineration of PVC releases HCl and risks dioxins; chlorinated solvents and CFC precursors have ozone and toxicity legacies	indicative

Other environmental impacts

Legacy mercury pollution from mercury cells; asbestos from diaphragms; acute toxicity in accidents; persistent organochlorines (PCBs, DDT, dioxins) from historic uses.

Levers to cut emissions

Renewable power purchase: power is about 90% of the footprint, so a zero-carbon grid cuts it to roughly 0.1 t per t
Oxygen-depolarised cathodes cut electricity by about 25-30% (indicative)
Demand response: chlor-alkali cells can flex load, earning grid revenue (indicative)
Use the hydrogen co-product (about 28 kg per t) as fuel or feedstock rather than flaring
Close mercury and diaphragm capacity

India

India's chlor-alkali runs on coal-heavy grid or captive coal power, so its footprint is higher than Europe's; producers are adding solar-wind hybrid power, for example DCM Shriram's 44 MW (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 electrolysis on renewable power	about 0.1-0.2 t CO2e per t (indicative)	depends on power price; flexible operation may lower cost	Indian producers adding captive solar and wind (DCM Shriram about 44 MW renewables, 2024)	Indian Chemical News June 2024; indicative

For a climate investor Chlor-alkali is one of the largest electricity users in chemicals, so firm low-carbon power is the main lever. Indian producers with captive coal are candidates for round-the-clock renewable power contracts and storage. Oxygen-depolarised cathodes and flexible operation are proven in Europe. What has to be true is cheap firm renewable power and buyers who pay for low-carbon PVC or caustic.