Written by Tanvi Mishra
Edited by Israa Zaheer & Emil Koch
A recent invention known as "green steel" has the potential to transform the steel industry and aligns with our future goal of transitioning away from a linear economy towards a circular one.
Transitioning towards green steel is less taxing on the environment than manufacturing standard steel and has added economic and human health benefits. Although the transition to green steel is eagerly anticipated, not enough businesses are utilising these techniques to create sustainable change.
What is green steel?
The creation of carbon-free steel is known as green steel. There are several ways to accomplish this. The removal of fossil fuels is the most common method. The most popular substitute for fossil fuels is hydrogen, which comes in a variety of colours, including grey, blue, green, pink, yellow, and turquoise. Electrolyzing hydrogen after splitting it with renewable energy produces green hydrogen, the only type produced in a carbon-neutral manner, and thus used to generate "Green Steel". Other hues of hydrogen are produced by coal or methane, both of which still emit carbon dioxide.
Using an electric arc furnace rather than a coal-fueled blast furnace is another method for producing green steel. Despite gradually replacing conventional furnaces, electric furnaces occasionally use non-renewable energy sources for power. The steel they create, in this instance, is thus not regarded as green.
Recycling is another method for creating green steel. This is the simplest method because steel is simply heated and reshaped instead of its iron ore being extracted. Recycling steel is better for the environment because it only uses 1/3 of the energy needed to extract it (GMS, 2022).
Production of green steel
Three steps make up the traditional steelmaking process: reduction, transformation, and forming. A reduction reaction leads to pig iron by removing oxygen from the iron ore. During the transformation stage, substances like nickel, chromium, manganese, or molybdenum are added to pig iron to produce a crude steel material. The final step involves forming the finished product by putting the raw steel through hot and cold processing steps.
Reduction results in the highest carbon emissions of these three steps. Green steel mainly targets this step by finding ways to eliminate the carbon emissions related to it.
Green Steel was first produced in 2021 by SSAB in Sweden using HYBRIT (Hydrogen Breakthrough Ironmaking Technology).
The distinction between a blast furnace process and the HYBRIT process is illustrated in the figure below. Standard steel production procedures are used by HYBRIT, but Green Hydrogen is used in place of fossil fuels to produce iron pellets and purify carbon. It should be noted that the iron created by HYBRIT is spongy rather than molten, giving it its highly metalized quality and superior mechanical and ageing properties (HYBRIT, 2022).
Impacts of Green Steel on Humans
Environmental damage and severe human health issues can result from pollution released by steel factories. One such example is a steel factory in Pittsburg, Pennsylvania, which contributed to elevated rates of cancer and respiratory conditions like asthma by releasing toxic and carcinogenic substances into the atmosphere. (2023, Washington Post). By switching to green steel, pollution that could harm people's health would be eliminated.
Green steel can benefit the economy in addition to our health. Since green steel is produced through recycling, it is more readily available than conventional steel. High demands can be satisfied as the ongoing mining of iron ore, which is a finite resource, would be needless. Green steel also has superior qualities, which would make it a valuable commodity in trade. Additionally, switching to green steel would generate employment, strengthening our economy further.
Impacts of Green Steel on the Environment
Today, 70% of steel is produced in a coal-fueled blast furnace, making the steel industry one of the most environmentally damaging and polluting in the world. Steel production accounted for 8% of all industrial carbon dioxide emissions in 2022, higher than any other heavy industry (Wermac, 2020). In response, lowering carbon dioxide emissions from the steel industry should be an essential step in achieving net zero emissions.
In addition to lowering carbon emissions from the steel industry, using green steel can help us reduce global waste. A method has been discovered by Professor Veena Sahajwalla, a professor at the University of New South Wales, to convert old rubber tyres into Green Steel. This has allowed for the diversion of over 2 million discarded rubber tyres from landfills.
In standard steel factories, toxic wastewater, carcinogenic chemicals, cyanide, sulphur compounds, ammonium, and ammonia are released into the environment. (The World Matters, 2023) The pollution of air, water, and land caused by these chemicals can result in numerous environmental problems. These pollutants can also be directly linked to acid rain, habitat destruction, and climate change. As it is far less polluting, the adoption of green steel will have a significant impact on the pollution problem in the steel industry.
Conclusion
A complete shift toward an economy based around green steel is crucial to enable us to transition into a fully circular economy. This has numerous benefits for us and our future generations in terms of helping to reverse climate change, boost our economy and improve overall human health.
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References:
[1] Chugh, A. and Taibi, E. (no date) What is green hydrogen and why do we need it? an expert explains, World Economic Forum. Available at: https://www.weforum.org/agenda/2021/12/what-is-green-hydrogen-expert-explains-benefits/ (Accessed: June 15, 2023).
[2] Ellerbeck, S. (2022) What is green steel and how can it help us reach net zero?, World Economic Forum. Available at: https://www.weforum.org/agenda/2022/07/green-steel-emissions-net-zero/ (Accessed: June 15, 2023).
[3] Fossil-free steel – a joint opportunity! (2021) Hybrit. Available at: https://www.hybritdevelopment.se/en/ (Accessed: June 15, 2023).
Green Steel (no date) Green Steel | SMaRT@UNSW. Available at: https://www.smart.unsw.edu.au/technologies-products/green-steel (Accessed: June 15, 2023).
[4] Hiremath, A. (2022) What is Green Steel and sustainable steel making?, GMS Leadership. Available at: https://www.gmsinc.net/article/green-steel-different-shades-of-steel (Accessed: June 15, 2023).
[5] Magazine, S. (2021) Fossil fuel–free 'green' steel produced for the first time, Smithsonian.com. Smithsonian Institution. Available at: https://www.smithsonianmag.com/smart-news/green-steel-produced-first-time-180978550/ (Accessed: June 15, 2023).
[6] Muldowney, S. (2020) How inventor Veena Sahajwalla Revolutionises Recycling science, INTHEBLACK. CPA Australia. Available at: https://intheblack.cpaaustralia.com.au/people/veena-sahajwalla-revolutionising-recycling-science (Accessed: June 16, 2023).
[7] Pandit, J.K., Watson, M. and Qader, A. (2022) Reduction of Greenhouse Gas Emissions in Steel Production. rep. Carlton, Victoria: CO2CRC Limited.
S., W. (2022) What is green steel?, What is Green Steel? Available at: https://www.wermac.org/steel/green_steel.html (Accessed: June 16, 2023).
[8] Vetter, D. (2021) How Sweden delivered the world's first fossil fuel-free steel, Forbes. Forbes Magazine. Available at: https://www.forbes.com/sites/davidrvetter/2021/08/19/how-sweden-delivered-the-worlds-first-fossil-fuel-free-steel/?sh=9ebc446b5530 (Accessed: June 16, 2023).
[9] Frazier, R. (2023) Groups, residents want EPA to protect mon valley from 'unacceptably high' levels of benzene pollution from U.S. Steel, The Allegheny Front. Available at: https://www.alleghenyfront.org/groups-residents-want-epa-to-protect-mon-valley-from-unacceptably-high-levels-of-benzene-pollution-from-u-s-steel/ (Accessed: June 16, 2023).
[10] Tons of Steel Produced (no date) The world counts. Available at: https://www.theworldcounts.com/challenges/planet-earth/mining/environmental-impact-of-steel-production (Accessed: June 16, 2023).
[11] Koch, T. (2019) THE DISRUPTIVE POTENTIAL OF GREEN STEEL, RMI.org. Rocky Mountain Institute. Available at: https://rmi.org/wp-content/uploads/2019/09/green-steel-insight-brief.pdf (Accessed: June 17, 2023).
Figures:
[1] Figure 1: What is green hydrogen and why do we need it? An expert explains. (2023, May 1). World Economic Forum. https://www.weforum.org/agenda/2021/12/what-is-green-hydrogen-expert-explains-benefits/; (06/15/2023)
[2] Figure 2: Vetter, D. (2021, August 19). How Sweden Delivered The World’s First Fossil Fuel-Free Steel. Forbes. https://www.forbes.com/sites/davidrvetter/2021/08/19/how-sweden-delivered-the-worlds-first-fossil-fuel-free-steel/?sh=9ebc446b5530
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