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Carbon-intensive sectors with few low-emission options

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Road freight (9%), Iron & steel (7%), cement (6%), chemicals (4%), shipping (3%), aviation (2.5%), pulp & paper (2%), and aluminum (2%) are key energy-intensive sectors/industries as they require higher energy densities and/or intense heat and are therefore classified as “hard-to-abate” (due to the challenges in reducing their CO2 emissions), leading the charge to green hydrogen economy.


Many of the sector’s upstream & downstream processes involve using thermal energy from gas or coal for heating, which can be decarbonized by using hydrogen or electricity [MPP, 2023].  But, low-carbon industrial techs for energy-intensive industries are currently at different levels of readiness: those still in pilot & demo phase may be crucial for reaching 2050 emission targets [ERA, 2023].


Iron & Steel


Steel is an extremely valuable commodity.  About 50% of the world’s steel production goes to construction, the automotive industry comes next.  Steel is one of the world's most-recycled materials, with a recycling rate of around 60% globally [TWC, 2023].  Nevertheless, although energy consumption per ton of steel has been reduced by around 60% since the 1960s, steel is still one of the world’s dirtiest industries: in 2021, around 7% of the global GHG emissions (29% of the global industry) resulted from it.

Steel use, recycling & production processes


Much of today's steel production uses coal (about 70% of the world’s steel); the remaining 30% is made through electric arc furnaces (EAF), which emit lower levels of CO2 than blast furnaces.  Coal is used to power sintering & pelletizing plants, as well as coke ovens, releasing CO2 in the process.  On average, 1.83 tons of CO2 are emitted for every ton of steel [SU, 2022].


Carbon steel (0.05 to 2.1 % carbon by weight) accounts for 90% of steel production.  Low alloy steel is alloyed w/ other elements, usually molybdenum, manganese, chromium, or nickel, in amounts of up to 10% by weight to improve the hardenability of thick sections.  Figure 1 and Figure 2 show conventional steel production process and green steel production process, respectively.

Other energy intensive industries


  • Cement (temp. range: 1,400 °C to 1,650 °C): developing countries account for about 73% of the global cement production.  Energy use of the cement industry in China in 2005 was about 50% of the energy consumption of the building materials industry.  Cement is an ingredient of concrete, used by humans for shelter for more than 6,000 years: half of the concrete ever produced is less than 20 years old; today, the annual worth of the global concrete industry is about USD 1 trillion [SC, 2020].  Novel approaches & materials could help the cement industry transition to a decarbonized future [MCK, 2023].

  • Chemical (about 1 kWh to produce a 2 liter bottle): a small number of products make up a large amount of energy consumption in chemical sector: ammonia is used to produce fertilizers, which accounts for about 1.2% of world energy use, and more than 90% of this energy is used in the production of ammonia [GEL, 2023].

  • Pulp & Paper (about 9 MWh to produce 1 ton of virgin paper): around half of the total energy consumed by the sector is used in pulping and the other half is used in paper-making, mainly due to the large amounts of water to be evaporated in drying pulp & paper.  Efforts are needed to incentive the deployment of industrial heat pumps, and innovation on techs that reduce the amount of heat needed for pulp & paper drying. There is growing ambition on electrifying heat in the European paper industry [IEA, 2022].

  • Aluminum (temp. range: 680 °C to 750 °C): given the considerable amount of electricity consumed in the aluminium sub-sector (In 2021, globally averaged, about 14 MWh of electricity are required to produce 1 ton of aluminum. [STAT, 2022]), decarbonizing its power sources would help reduce indirect emissions [IEA, 2023]. Secondary aluminum production has a significantly lower carbon footprint (0.5 t CO2e/t Al vs up to 16 t CO2e/t Al).

  • Glass (temp. range: 1,500 °C to 1,600 °C): the energy requirements to produce 1 kg of glass are btw 2 to 3 kWh due to the high melting temperatures, and approximately 0.74 kg of CO2 is emitted in the process [SD, 2022].

Figure 1:  Steel production - conventional process

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Figure 2:  Steel production - green process

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Fig 1 Hard steel convent
fig 2 hard steel green
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