FEATURE: E&T MAGAZINE – Gearing up for green steel: how the sector plans to decarbonise

The steel sector, which is accountable for an estimated 7-9 per cent of global carbon emissions, has set its sights on decarbonisation, having already reached its first technological breakthrough. While greening this high-carbon-intensity commodity is no easy feat, its progress could provide a blueprint for other comparable commodities.

Steel is the world’s largest materials industry and is ubiquitous in everything from car bodies to construction and wind turbines. Therefore, its cost-effective decarbonisation is integral to the global net-zero agenda, as well as for individual companies that have themselves set similar ambitions.

Last year a breakthrough proved it’s technologically possible to decarbonise the versatile alloy. HYBRIT, a consortium consisting of Vattenfall, steel producer SSAB and miner LKAB, produced the first ever fossil-fuel free steel using green hydrogen.

HYBRIT’s aspiration isn’t unique. Driven by the SteelZero initiative, set up in 2020 by The Climate Group to drive action to decarbonise the sector, key industry stakeholders have made a flurry of commitments and investments to reach this milestone by 2050. Industry momentum is expected to continue in 2022 with the first industrial pilot projects expected by the middle of the decade.

Around 71 per cent of steel produced today comes from an iron-ore-based method. This typically uses a blast furnace at temperatures of around 1,500°C in which carbon, usually coal, is used to remove oxygen and impurities from the ore to make pig iron. The latter is then turned into steel via a basic oxygen furnace whereby oxygen is blown onto the liquid iron to burn unwanted elements. The other 29 per cent is made using scrap and Electric Arc Furnaces (EAF), which use an electrical current to melt scrap steel. This is on average 25 per cent less carbon-intensive than the other method.

Steel producers are considering several ways to decarbonise these processes. At the HYBRIT pilot plant in Luleå, Sweden, engineers opted to replace the blast furnace process with a ‘direct reduction’ that uses hydrogen made from water and renewable electricity to reduce iron-ore pellets manufactured by LLKB without fossil fuels to sponge iron, which is then turned into steel. The temperature needed for the reduction process is much lower than in the blast furnace and produces only water vapor as a by-product, removing 90 per cent of CO2 emissions. The technique is powered by energy from the national grid, which in Sweden is largely fossil-free, consisting mostly of hydro and wind power. SSAB hope to turn their research into a full-scale pilot plant by 2026.