New life for old manufacturing plants: Green steel technologies.

Decarbonization of the iron and steel value chain is crucial to achieving zero-emission targets.

Iron and steel are important raw materials in almost every aspect of modern life, from construction to transportation and energy.These are the  most energy- and emission-intensive industries on the planet.

Iron and steel production is one of the largest users of carbon, accounting for about 8 percent of annual CO2 emissions.

Emissions from steel production are generally difficult to reduce because current efficiency and reduction options are limited and some alternative technologies are expensive. Therefore, it is important to accelerate the global diffusion and commercialization of low-carbon steel production technologies, such as replacing carbon-based reduction with renewable electricity, green hydrogen, or carbon capture, storage, and utilization.

Steel Plant manufacturing process

Steel plants consist of multiple units and it depend on the manufacturing method one is opting for.

How old manufacturing plants can adapt these technologies?

Example case of Tata Steel based on assumption modeling


energy consumption at Tata steel


Step 1: Carbon and Energy Auditing

  1. A layout of the entire steel plant should be there to start auditing. Identify the method used for steel production and have a thorough understanding of all production units at the plant.
  2. From raw material flow to process flow, the checking of all parameters such as set-up time, pull system, production leveling, lot size, quality control circles, group technology, and total productive maintenance needs to be analyzed.
  3. The value chain must include the following: extraction of raw materials (drilling, blasting, and mining); processing (crushing, screening, and beneficiation); transport to port (rail or road); preparation of raw materials (sintering and granulation); iron production (blast furnaces); and steel production.
  4. Create a base-case “fossil fuel” value chain for typical materials and identify different opportunities for each ore type in the value chain.
  5. Map changes in energy use and emission profiles at each stage of the value chain and determine appropriate measures for each stage and the steel price per ton for each scenario.
  6. Determine the quantity and type of low-carbon and renewable energy alternatives required, as well as the reserve requirements, to ensure continued operation under each scenario.
  7. Identify “biggest benefit” opportunities to reduce emissions throughout the value chain, including alternative solutions with low CO2 and/or renewable energy at each stage of the value chain.
  8. identifying barriers at each stage of the value chain that limit the adoption of low-emission or renewable energy solutions and key current and future potential technological solutions; and identifying energy and processing risks and opportunities at each stage of the value chain, including an assessment of the time frame required to implement different solutions.
  9. calculating the overall amount of CO2 produced at each and every step of the process life cycle and reporting the same data for further evaluation. It can be done by installing sensors, IOT technology, and visualization tools to collect the sampling and data from the entire unit.
  10. culture of waste elimination, root cause analysis, mistake proofing, visualization (visual plant), respect for employees, simplification (focus on shop floor), and standardization of work.


Step 2: Identification of Obstacles or Limitations

Let’s assume the scenario of a plant where the steel-making process is completed in five steps.

The following factors are responsible for the gaps in CO2 emissions and energy consumption at Tata Steel:

Coke Making: Lower coke, gas, and tar yields; higher steam consumption; and higher fuel rates are largely responsible for the gaps.

High Coke Blow, Iron Making Sintering. Higher coke rate; lower hot blast temperature; higher steam consumption; poor solid waste recycling; lower top gas pressure (no TRT).

Steelmaking: lower recovery, large slag volumes, and higher consumption Mill: lack of hot charging.

Low furnace efficiency, high power consumption

Boilers and Power: inefficient boilers, low-pressure steam generation, poor power house generation efficiency, and large auxiliary power consumption

Auxiliaries Large bleeding losses, steam and compressed air leakages, a large fleet of smaller carriers consuming more diesel, and several auxiliary facilities like refractories and lime production, foundries, engineering shops, etc. (which are outsourced in modern plants)

The main process for producing CO2 and other harmful gases

The main process steps that produce carbon dioxide in the production of iron and steel are the production of coke and the production of hot metal in the blast furnace. Ancillary facilities, such as power plants, also produce large amounts of carbon dioxide.

Direct emissions – BOF plants are typically between 1.8 and 3.0 tons of carbon dioxide per ton of steel produced.
DRI-based EAF plants emit approx. 2–3 tons of carbon dioxide per ton of steel if carbon-based or 0.7–1.2 tons per ton if gas-based. Emissions from EAF plants made on the basis of scrap metal are mainly indirect: the emission of carbon dioxide is not produced by the steel plant, but by the power producers supplying the furnaces with electricity.
For a typical EAF, direct emissions are typically around 0.06–0.1 t/t; indirect emissions can add another 0.4t/t CO2.

Step 3: Market Dynamics and Economic Possibilities


  1. The implementation of scenarios in identified areas; In terms of mineral resources, consider co-locating energy solutions with other industries to increase profitability.
  2. The auditing process provides a clear perspective on how to grade process emissions, beginning with the most emitting phases of the process and progressing to the least emitting phases.
  3. Replacement of new methods and technology should be prioritized based on the circumstances discovered.
  4. They can prioritize which equipment or cycle process requires more attention in order to decarbonize the emission of CO2 and other harmful gases.
  5. The process must be limited from the beginning to the end.
  6. Every stage would require a different set of technologies and methods in order to control the emissions.
  7. Checking the availability of renewable energy solutions and hydrogen production (existing and planned),
  8. Land availability, environmental, and heritage aspects are affected by land use and support services. infrastructure requirements (port, railway, road, energy, water, and air transport).
  9. capital costs, infrastructure life, and the possibility of joint use; and support service requirements, workforce capabilities, and availability.


green steel

Cost Component:

Cost breakdown 

Cost components

Elements of  Cost Curve 


Energy (Electricity and Natural gas)

Energy (Coke oven gas, Blast furnace gas, Basic oxygen furnace gas, Corex as, Custom iron gas, Custom steel gas, Heavy fuel oil, Natural gas, Thermal coal, Other fuel and Steam) 




Raw Material 

Raw Material (Iron ore, Scrap, Limestone, Oxygen, Ferrosilicon and Reductants)

Iron ore (Lump ore, Sinter fines, Pellet feed, 3rd party pellet and 3rd party sinter) Reductants (Coking coal, Injection coal, Anthracite, 3rd party coke,

 Injection natural gas, Injection heavy fuel oil and Injection other fuels) Metallics and ferroalloys (3rd party scrap, 3rd party direct reduced iron, 3rd party pig iron, Ferroalloys, Aluminium, Zinc and Tin) Purchased semis (Purchased slab, purchased hot rolled coil, purchased cold rolled coil and Purchased billet) 


Credit (savings from recycled scrap and self-power generation) 

Credits (Blast furnace gas credit, Basic oxygen furnace gas credit, Corex gas credit, Custom iron gas credit, Custom steel gas credit, Steam credit, Scrap reverts, Fe reverts, Tar, Benzole and Slag) 


Other (fluxes and other consumables) 

Other consumables (Fluxes, Electrodes, Refractories, Oxygen, Inert gases, Industrial water, Bentonite, Cold rolling oil, Pickling acid and Paint) Other costs (Overheads, Sustaining capital, Interest on working capital, Rolls and roll shop, Parts and spares and other costs) CO2 costs 



  • The steel manufacturer will assess the future dynamics of the iron ore mining, ironmaking, and steel markets to assess the potential opportunities and risks arising from action or inaction under each scenario.
  • Jurisdiction and mineral resource differences, likely timelines, and drivers of change in each jurisdiction, including identifying who are likely to be first movers; energy cost and carbon pricing models to evaluate alternatives and determine sensitivity; cost competitiveness of renewable energy sources and hydrogen production risk; and the effect of action or inaction on
  • input availability, technology, and demand for crude steel; required technology impact and price points for energy and technology solutions to enable manufacturers to be cost competitive; and compares the cost per tonne of steel at each stage of the value chain for each scenario with the base case (including amortized capital costs).

Step 4: New methods and implementation for possible solutions


  1. Moving to new technologies and processes to produce low-carbon steel may require the development of new supply chains and business models to provide the necessary production inputs (e.g., green hydrogen).Prioritizing activities that improve the manufacturer’s ability to develop tools to model, analyze, and optimize single-input, multi-output integrated systems and multi-input, multi-output integrated technology
  2. Identify appropriate points of contact between and among human capital and all departments involved in the production, processing, supply, storage, and use of clean hydrogen, and explain the responsibilities and potential regulatory barriers of the outcome.
  3. This shift could create new opportunities for developing countries to integrate into green steel supply chains. Developing countries should be supported to take advantage of these opportunities, taking into account that the demand for steel products will be concentrated in developing markets in the future and the need to ensure a fair transition to a low-carbon economy.
  4. After implementation, we can measure the parameters of reduction for overall operations and processes.
  5. Concentration of steel production at the most efficient installations.
  6. Rebuilding or modernizing plants to improve efficiency
  7. Process step removal
  8. Energy optimization in existing processes.
  9. Use of natural gas instead of coke in blast furnaces.
  10. Recommendations for changes to support the deployment of pure hydrogen and identifying geographic zones or regions where the deployment of clean hydrogen technology could be effectively and economically implemented to transition existing infrastructure to clean hydrogen to support the decarbonization of all related economic sectors.

Roadmap for IR4.0


  1. A roadmap towards IR4.0 is required, as is a strategy to dwell on the new and discard the old concepts at every stage of the life cycle process.
    Cost-effective solutions need to be built around the audit report.
  2. Reduction in ash percentage in BF coke to 17.5% by using low-ash coal reduction in alumina content in blended fines by 0.20% through improvements in crushing and screening facilities
  3. The “F” Blast Furnace is being upgraded, while the “B” Blast Furnace is being closed.
  4. Waste heat recovery from ammonia incinerators can be achieved by installing a waste heat boiler in a new incinerator of 10 TPH capacity.
    Improvement of condenser vacuum at Power
  5. By renovating primary cum deep coolers and reducing leaks, CO gas yield can be increased to 330 Nm3/tdc. waste oil injection into blast furnaces along with tar (10 barrels per day).
  6. Energy-saving items at Oxygen Plant (replacement of an electrical heater by a steam heater; replacement of a heat exchanger by a direct cooler).
  7. Columns of air separation units (ASU1 and ASU2) were replaced with new columns with structured packing.

Examine low-emission steel manufacturing technologies and methods for producing green steel.


low emission steel making technology

Replace coking coal with biofuel:

Biofuel, although carbon-based, does not produce greenhouse gases when burned, so it has a lower environmental impact. Using biofuels in BF-BOF can reduce carbon dioxide emissions by half. Although it is a mature technology, the challenge is its feasibility on a large scale, which depends on availability.

Reducing carbon emissions through electric arc furnace (EAF)

 Waste-based EAFs: 

Increasing the proportion of waste-based EAFs maximizes secondary flow and recycling by melting more waste. High-quality waste products are mainly required for the production of high-quality products, which are mainly produced in an integrated way. However, if high-quality chip is not available, low-quality chip can be mixed directly with reduced iron to provide high-quality feed.

Direct Reduced Iron (DRI):

In this process, the metal is reduced directly from the ore in its solid state without the need to melt it. Natural gas is used as a reducing agent, which helps reduce carbon dioxide emissions by 50% compared to the traditional BF-BOF route. DRI can be mixed with lower-grade residues to provide certain properties. The challenge is the dependence on the availability of natural gas.

DRI and EAF use hydrogen: 

In the production phase of DRI, fossil fuels are replaced by hydrogen produced by renewable energy. It is a technically proven production method that enables virtually emission-free steel production.


The green hydrogen market is expected to grow from USD 676 million in 2022 to USD 7,31million by 2027. The CAGR is 61.0% during the forecast period. Factors influencing the market include falling costs of renewable energy generation from all sources, advances in electrolysis technologies, and high demand for FCEVs and the electric industry. Green hydrogen offers a sustainable alternative to fossil fuels in several end-use areas.

Green hydrogen based on alkaline electrolysis accounted for the largest share of the total green hydrogen market.

Alkaline electrolysis-based green hydrogen accounted for 61% of the total green hydrogen market by volume in 2021. Alkaline electrolysis is the most widely used technology for green hydrogen production worldwide.


Two electrodes are immersed in a basic electrolyte solution (such as sodium or potassium hydroxide) and separated by a membrane, a non-conductive permeable membrane, in alkaline electrolysis. Because hydrogen ions do not readily diffuse into the electrolyte solution, alkaline electrolysis produces purer green hydrogen than PEM electrolysis and is therefore more widely used.

hydrogen steel making

Use of Green Steel

Green Steel: This refers to a steel production process that reduces greenhouse gases, lowers costs, and improves steel quality. This can be done by using gas instead of coal, recycling steel, etc.



Steel cannot be green in its entirety:According to a report by the NGO Global Energy Monitor, the transition from traditional (coal) blast furnaces to electric arc furnaces is “stagnant” and far behind decarbonization.


Green Hydrogen is a renewable energy source.

Price of Green Steel: Producing clean hydrogen at scale will require billions of dollars of investment in renewable energy production.

Market intervention

A differentiated low-carbon steel product that allows supply and demand dynamics to create a premium for a more efficient supplier

Diversification of assets reduces exposure to medium- to long-term market development toward a low-carbon future. • New vehicles extend intellectual property beyond individual units.

  • Carbon taxes or similar mechanisms to reduce the benefits and costs of carbon-intensive production
  • industrial self-regulation and critical-scale carbon reduction obligations
  • Carbon-based import tariffs protect local markets against carbon leakage (i.e., competition from high-carbon imports);
  • Carbon efficiency requirements in public and/or private procurement

Financial resources • State or voluntary support for added value in low-carbon steel production can reduce uncertainty in technology investment development. • Late R&D support can bring technologies currently in a test phase to market.

pressure from investors on steel companies to disclose and improve their carbon emissions. securities programs or other financial instruments to manage the potential depreciation of high-carbon production assets.


Boost high-quality production. Iron ore mining companies are already prioritizing the production of higher-quality ores, but they need to do more. Ores with more iron and fewer impurities allow producers to efficiently produce crude steel with a higher refining value. Demand for such ores is increasing as steelmakers move away from BF-BOF plants and toward DRI-EAF.

Production technology. The basic natural gas The DRI/EAF manufacturing method is already well-established and widely used in certain markets that benefit from a plentiful supply of cheap natural gas. In the future, changing the process to a fully hydrogen process is technically possible, although the overall costs are still high and the technology has not yet been widely proven. On the other hand, it is considered relatively easy to convert the natural gas DRI/EAF production method to hydrogen.


Green hydrogen pricing will eventually fall, making it a cost-effective option to consider. 

Digital Transformation at Core


The graphic above highlights the most important trends in metal production today. These trends are driven by various technologies, including automation and robotics, artificial intelligence (AI) and machine learning (ML), the IIoT, and analytics. faster and more efficient processing.

digital workforce via digital connectivity (mobility in conjunction with VR and AR).

Integrated enterprises, platforms, and ecosystems for supply chain problem identification and root cause analysis

Next-generation analytics and decision support to increase operational agility and efficiency

Capabilities for Sustainable Steel Transformation

Virtual Twin Experience: This provides an accurate virtual representation of your supply chain and operations, allowing you to test and optimize processes and resources before implementing them in the real world.

Sales and Operations Planning: Bridging the Gap between Business Strategy and Operations with CO2 KPIs that can be factored into the optimization strategy and used for compromises during planning and reporting

Master Production Scheduling (MPS): helps refine supply and demand data and forecasts to deliver accurate and timely production plans across the manufacturing supply chain, including improving delivery efficiency for customer orders with more realistic delivery expectations.

Detailed Programming: Helps to plan material flow, combine orders, and create lots to create ideal batches to achieve the right balance between optimal production efficiency and best delivery capability.

Collaboration empowers steelworkers to innovate by bringing people together in a structure that drives discovery, analysis, and better collaboration.

Manufacturing Operations Management (MOM): A comprehensive core platform for managing and synchronizing cutting-edge operations all over the world.

AI/ML-based platform: It helps create the value network of the future through closed and intelligent decision automation in all parts of the supply chain.


Taking another case from India for the hydrogen reduction act

As per the Ministry of Steel, India

  • India is currently the world’s 2nd largest producer of crude steel in January–December 2021, producing 118.20 million metric tons (MT) of crude steel with a growth rate of 17.9% over the corresponding period last year (CPLY).
  • India is the largest producer of direct reduced iron (DRI) or sponge iron in the world in January–DDecember 2021, producing 39.04 MT of sponge iron with a growth rate of 16.2% over the corresponding period last year (CPLY).
  • India will be the 2nd largest consumer of finished steel in 2021 (106.23 MT), preceded by China as the largest steel consumer, as per the World Steel Association.
  • Capacity for domestic crude steel expanded from 137.97 MT in 2017–18 to 154.06 MT in 2021–22, a compound annual growth rate (CAGR) of 3.7% during this five-year period.
  • Crude steel production grew at a rate of 4.2% annually (CAGR) from 103.13 MT in 2017–18 to 120.29 MT in 2021–22.



Scrap availability

Increasing the use of scrap metal, improving resource efficiency, and increasing material recycling are critical to mitigating negative environmental impacts as India continues to grow. This also includes increasing the use of waste, which reduces the amount of raw materials needed in the primary production of steel, leading to a positive energy and emissions effect.

Designing steel products to facilitate recycling and building appropriate recycling infrastructure can be done now, and the MoS Steel Recycling Policy is a positive first step. This can increase the use of scrap metal in the BF-BOF route and EAFs to reduce energy consumption and greenhouse gas emissions.

Source: Teri,Material, energy and emissions benefits of scrap-based production

Imported scrap comes mostly from developed countries, with the top five exporting countries including the United Arab Emirates, the United States, the United Kingdom, Singapore, and the Netherlands.

Importing higher-quality scrap has been important in maintaining the quality of steel produced on the power line, which is often a combination of local scrap and direct reduced iron (DRI).

 It is also used to reduce energy consumption on the BF-BOF route by using up to 20% scrap iron in the main oxygen furnace, although this is usually “in-house” and not imported.

The limited availability of scrap metal in India means that most BOFs use less than 10% of it today. The availability of imported scrap is expected to decrease steadily as developed countries begin to implement stricter emission reduction policies, including net zero targets.

Achieving such goals requires higher waste recycling rates in those countries to reduce domestic steel production via the primary route. In line with the international reduction in scrap availability, the Steel Scrap Recycling Policy assumes no scrap imports by 2030 and presents a strategy to increase the domestic availability of scrap steel through improved recycling.


Consequently, the Ministry of Steel expects the availability of domestic steel scrap to increase to approximately 50 million metric tons by 2030. As a share of total steel demand, this is around 20%, indicating that even with an ambitious steel scrap policy, new primary steel production capacity is needed to meet growing demand.


Possible scenario

Current blast furnaces are constantly being decommissioned when their economic life is over. By 2060, there will be a limited number of blast furnaces left, and those that are will be equipped with carbon sequestration technology. Coal-based direct reduction units have a shorter lifespan than blast furnaces, so in that scenario, they will be phased out by 2050 and replaced by natural gas and hydrogen-based direct reduction units.

In such a scenario, the main fuels of the iron and steel industry will change significantly. Currently, the iron and steel industry consumes about 60 Mt of coking coal, more than 80% of which is imported.

Demand for coking coal will begin to decline in the 2020s as gas-based power is introduced, paving the way for most of the direct hydrogen reduction by 2060. By 2060, industry could consume about 20 Mt of low-carbon hydrogen (which in turn would require about 1,000 TWh of electricity) and 250 TWh of electricity for EAFs using DRI and scrap.

While a reduction in energy imports from coal and eventually natural gas would bring significant benefits, the speed and extent of renewable energy expansion would prove to be a challenge. To accomplish this, we estimate that the price of coal for the steel industry in 2030 will be around $40 per tonne of CO2.

This would make direct hydrogen reduction competitive with BF-BOF plants, assuming a hydrogen price of $2/kg. In the future, the increase in the price of coal would ensure the continued gradual removal of natural gas in the direct reduction process, which would also be helped by the decrease in the price of green hydrogen.

The Future of Carbon-Neutral Steel

Although there are challenges in applying these alternative technologies to the production of carbon-neutral steel, manufacturers are working on several initiatives with the help of governments and technological innovators.



Most of the projects are concentrated in Europe thanks to the support of the European Commission, which aims to make the EU carbon neutral by 2050. In order for the rest of the world to follow suit, it is important that steel producers assess, evaluate, and decide on technically and economically viable ways to reduce their carbon footprint. Accelerating the transition from electric arc furnaces to steel production and scalable technology for green or blue hydrogen production

future of steel

In a global environment where renewable energy costs are constantly decreasing, with tight carbon regulations and new technologies entering the commercial pilot phase, promising technologies at only 20-30% higher costs, low-CO2 processes make economic sense.

Today, almost a billion tons of primary steel are supplied, but the supply of waste continues. increases over time, the entire increase in demand is expected to be covered by recycled steel. As a result, the demand for iron ore reduction capacity is projected to remain roughly stable over the same period. Even in scenarios where demand reduction is used to reduce carbon dioxide emissions, the residual demand for primary steel in 2050 is 550–750 million tons per year.

Globally, carbon dioxide emissions from steel mills are viewed as a serious issue. By implementing more recent technologies and streamlining procedures, the steel industry has decreased CO2 emissions by 15-20% during the past 20 years.

With the use of new technology and controls, an additional decrease of 15-20% is anticipated during the following ten years. Only the use of technology such as hydrogen for green steel, CO2 capture, BF and CO gas injection into blast furnaces, and iron ore smelting will result in significant reductions in CO2 emissions. 

Another critical factor is increasing the use of recycled steel. 

The life cycle analysis of steel goods promotes consumer confidence while reducing environmental impact and enhancing product quality, strength, and weight.

Plasma directs steel production and electrolytic processing—both of which are themselves in development. Their technical and economic viability in large-scale production has not yet been tested, leaving some uncertainty regarding their industrial use.

H2-based reduction technologies are more advanced and riskier, but not without challenges.

So far, for example, there are not enough large-scale H2 electrolyzers, which is a prerequisite to producing enough H2 for the reduction process. For example, the world’s largest electrolyzer.

H2 with a capacity of 100 MW is planned for Hamburg. Ignoring any level of efficiency or potential Regardless, we see direct reduced iron based on H2.either in a pit furnace or in a fluidized bed. as the dominant technology of the future in the production of carbon-neutral steel. We expect steelmakers to support the DRI ram furnace process. In addition to the promise of future carbon neutrality, it offers short-term transitional benefits because it is ready to use. DRI can be fed into existing scrap blast furnaces in the form of ductile iron, making them instantly more CO2-efficient. It also creates a functional breathing space that replaces the

In ram furnaces, blast furnaces are used. In the second transition phase, the BOF can be maintained with the new electric arc furnaces until capacity is sufficient to transition to a fully H2-based DRI shaft furnace method. Then it only adds green electricity.



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