Green Steel The road to climate-neutral steel production and beyond
It will not be possible to stop the rapid rate of climate change without the steel industry transitioning to Green Steel. The Swiss Steel Group has published a White Paper that outlines strategies to decrease the ecological footprint of steel production.
Without measures being taken in the steel industry, decarbonization of global commodity flows is not possible and climate change cannot be stopped. Steel as a material contains a very high percentage of what is known as “embodied energy” that is part of almost every product and many, many services, and thus their CO2 footprint. Embodied energy is the gorilla in the room, the monster that no one wants to see. In reducing its own footprint and its more accurate documentation within the framework of the groupwide initiative “Green Steel”, Swiss Steel Group (SSG) aims to reduce emissions to near zero. These efforts, however, are also meant to encourage customers and serve as a call to cooperate with science and the public. This will intensify the effect of efforts beyond the steel industry.
The steel industry distinguishes between two production routes, the primary and secondary route, respectively, using the blast furnace and the electric arc furnace route. In a blast furnace route, mined iron ore is melted into pig iron and ultimately into steel. This process produces new steel of the highest quality grades, often with very high CO2 emissions. The reducing agent is primarily bituminous coal although tests with hydrogen are currently being conducted. While fossil coke as a reducing agent produces CO2 as a waste product, steam is produced when hydrogen is used instead. The secondary route with the electric arc furnace works exclusively with steel scrap. This pathway thus uses considerably less energy and emits much less CO2 than the primary route. The smelting process takes place in electric arc furnaces and is thus much simpler to decarbonize than the blast furnace route. On the one hand, the main source of energy is electricity and, on the other, the process uses much less energy and needs fewer energy-intensive intermediate stages.
SSG has decided to pursue the electric arc furnace route exclusively in their steel mills and succeeded in reducing its emissions far below the industry average. This route is well-established and proven, especially given the fact that steel is the material most frequently recycled worldwide. Still, there are also major challenges on the electric arc furnace route. For a long time, it was not possible to produce all steel grades due to unavoidable trace elements. The available scrap volume is not always the same, and quality scrap needed to produce a precise steel grade is often lacking. Quality or new scrap is the single-origin scrap stemming from pressing and fabricated sheet works like the gratings produced from large steel strips when individual parts are punched out. Quality scrap, however, is also obtained from chips produced by machining processes in manufacturing such as cutting, turning, drilling, and sawing. In some machining processes, up to 90 percent of the starting material winds up as so-called new scrap. This scrap is highly sought after, expensive and will be even more valuable going forward because more and more of it is being used to control the quality of steel in the furnace.
A decisive and very complex part of the electric arc furnace route is thus scrap logistics. Compared to the blast furnace route where a single contract with a mining company can ensure the supply of raw material for years on end, the electric arc furnace route requires an elaborate collection and sorting system in cooperation with local companies and scrap dealers who have to deliver scrap in increasingly better quality with ever more elaborate and more expensive methods. A major ecological advantage of the electric arc furnace route is that the raw material can often be procured within an 80 to 100-kilometer radius. Transport routes are short, and the corresponding emissions are almost insignificant. On the blast furnace route, European companies import iron ore primarily from Brazil and coal from Australia and until recently from Russia.
SSG is focusing on three strategic approaches in production processes. Each enhances the effect of the other two and together they drastically reduce the impact on the climate, the company claims.
The Scope 1 reduction consists of the replacement of natural gas, particularly in rolling mills. Hydrogen, synthetic gases, biomethane or synthetic methane are to be used in the medium term. Except for biomethane, all these gases are produced by means of more or less sophisticated intermediate stages from electricity which in future is to be available at low cost or even negative prices when generated by hydroelectric installations, wind turbines and photovoltaic systems.
Further potential for reducing the amount of CO2 on the electric arc furnace route lies in the use of declared green energy. This considerably reduces the footprint even more. In the Swiss Steel Group plant in Emmenbrücke, Switzerland, this step has already been taken. The plant only uses electricity supplied by Swiss hydroelectric power stations. The site’s power consumption is equivalent to that of a Swiss city with a population of 62,000.
The greatest and by far most effective means of reducing the carbon footprint is switching from pure primary alloys such as ferrochrome, ferronickel, ferromanganese, or ferromolybdenum to high-alloyed scrap in the production of high-alloyed and stainless steel. The percentage of alloying surcharges specifically in high-performance steel is at times over 30 percent, and their procurement is energy and CO2-intensive. They also in part come from countries that are politically instable or under international sanction, particularly the important auxiliaries, specifically nickel and chromium.
That is why it is so important in the future both for ecological as well as political reasons to rely more on quality scrap for alloying instead of pure metals. To be able to manufacture high grade steel using highalloyed scrap, however, new metallurgical developments are needed in which the metallurgical lab of the Swiss Steel Group company Ugitech in France has made a mark. One of these improvements is the project Ugi’Ring, which at Ugitech is promoted together with regional partners. Its aim is to produce primary alloys from waste products such as batteries, catalytic converters, and similar products to become independent of suppliers of these elements from producing countries that are unstable politically.
In future, Green Steel, however, will be much more in future than just an eco-label for steel. Green Steel defines the reduction path to be taken by industry players such as the Swiss Steel Group to lower the impact on the climate. It is also an invitation to business partners, researchers, authorities and external organizations to decarbonize the economy together. Because if decarbonization doesn’t work in the steel industry, it won’t work anywhere.