The chemicals sector has a significant carbon footprint for two reasons. One, most chemicals use oil as the main feedstock, and thus comes with an embodied carbon. The other part of the industry’s CO2 emissions come from the production processes of chemicals - mostly due to the amount of energy used to produce key building chemical blocks such as ethylene, and in some cases also from CO2 emissions that are actually part of the reaction process - the prominent example is the production of hydrogen from methane.
The global chemicals sector (excluding emissions from the fertilizer value chain) generates about 600 million tons of CO2 emissions annually. Of this, ethylene production alone emits about 220 million tons of CO2 emissions per annum, methanol about 150 million tons per annum and polypropylene about 120 million tons emissions per annum.
The world uses millions of tons of synthetic fertilizers every year. And the fertiilzer production value chain has a very high CO2 footprint. A part of the CO2 emissions in fertilizer production happens during hydrogen production, which is currently done through steam reformation of methane. CO2 emissions also take place during the production of ammonia. About 850 million tons of CO2 are emitted annually by the fertilizer industry value chain, with about 350 million tons from the production of hydrogen and 500 million tons from the ammonia production process.
Decarbonizing the sector would require decarbonizing hydrogen production - possibly through green electrolysis - and also reducing the energy requirements for ammonia production, or electrifying ammonia production and using renewable power for the electrification. All these efforts are in their initial stages.
The 2020-2030 period will witness decarbonization efforts and innovations through reducing the amount of energy needed for chemicals production, electrifying some of the production processes (for instance, ethylene and ammonia production), recycling end chemicals and plastics so that lower amounts of chemicals need to be produced in the first place, and use of bio-based raw materials instead of petroleum. Currently, there’s significant progress in three of the four - energy efficiency in chemical production, recycling, and bio-based chemical alternatives. Electrification of key chemical production processes is at a very early stage but could see action post 2025.
Worldwide, production of primary chemicals emits about 1 billion tons of CO2 annually. If we include emissions from hydrogen production for ammonia, the total primary chemical industry emissions increase to about 1350 million tons of CO2, or about 2.5% of total annual global greenhouse emissions.
Of the above, about 500 million tons can be attributed to ammonia production alone. Further, 210 million tons are from the production of ethylene, 125 million tons from methanol production, 110 million tons from the production of polypropylene, and about 40 million tons from the production of benzene/toluene/xylene (BTX). Hydrogen production from natural gas, used mainly as a feedstock for ammonia production, results in an additional 350 million tons of annual CO2 emissions.
Adding emissions from upstream activities related to petrochemicals in oil & gas, downstream production of organic and inorganic chemicals, and emissions post-use disposal of chemical products, the total emissions from the global chemical industry is over 3 billion tons of CO2 per annum.
A large portion of the CO2 emissions in the primary chemicals production happen owing to the use of fossil sources for heat energy required for these thermochemical reactions. In addition to these energy related emissions, there are significant process CO2 emissions from the chemical reactions for hydrogen production - these happen owing not to fuel use for energy but from the thermochemical processes that produce hydrogen.
Heat is the dominant form of energy used in the chemical industry production setup, with electricity currently playing only a minor role. The heating infrastructure is configured for use of fossil fuels - mainly natural gas and oil. The processes for producing hydrogen, ammonia and the other basic chemicals are well established and their infrastructures highly invested into.
None of the above emissions is easy to abate.
Compared to other prominent industries with similar emissions (textiles, for instance), the chemical industry has been under less scrutiny and pressure thus far on the decarbonization front.
But the scenario is changing fast. Globally, the key chemical industry stakeholders are beginning to take note.
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