Decarbonisation roadmap
The European objective of the ‘Green Deal’ for climate and energy, by 2050, requires the achievement of the “Net Zero Emission Target” of CO2 emissions, by 2025, with intermediate reduction of 55%, by 2030, compared to 1990 levels. The steel industry, responsible for 5% of total CO2 emissions in Europe (EUROFER data), 7% globally (WorldSteel data), is one of the most ‘hard-to-abate’ production sectors. The adoption of low-carbon steel production technologies is then needed.
The report highlights the current technological status, the investment needs, and the current decarbonisation strategies. They can essentially be summarised in three ‘pathways’:
- targeted adoption of actions aimed at reducing emissions in the production process (Process Integration, PI);
- significant limitation of the use of carbon in the production process. This can be done thanks to the use of alternative materials (Smart Carbon Usage, SCU), to the separation, the capture or the use of CO2 produced (Carbon Capture and Usage, CCU; Carbon Capture and Storage CCS)
- fossil carbon elimination (CDA, Carbon Direct Avoidance), through the development of innovative steel production processes with fossil-free reducing agents and renewable energy sources.
These lines can be integrated with a parallel circular economy strategy, with virtuous reuse of waste products as raw material (e.g. use of slag for energy recovery or biomass to replace fossil coal).
Focus is given on the relationship between production cycle and environmental impact. The ‘primary’ cycle, or integral cycle, involves the production of steel from iron ore, and the ‘secondary’ cycle, or electric cycle, involves the recovery of steel scrap as raw material to be melted in electric arc furnaces (EAF - Electric Arc Furnace). The integral cycle, consisting of a blast furnace (BF - Blast Furnace) and a converter (BOF - Basic Oxygen Furnace), produces most of the world's steel and high energy efficiency, but produces a greater quantity of CO2 equivalent emissions (1.9-2.1 tons of CO2 generated for each ton of crude steel produced, compared to about 0.4-0.6 of the electric cycle).
A ’clean’ way of producing steel is based on direct reduction (DR), consisting of reducing iron ore directly to solid metallic iron (without the intermediate stage of producing liquid pig iron), with a solid (usually coal) or gaseous (natural gas) reducing agent. In this way Direct Reduced Iron (DRI) is produced. The DRI (possibly transformed into briquettes, Hot Briquetted Iron, HBI) is melted in an electric furnace, producing liquid steel, similar to the liquid steel produced by the BOF converter, with strong emission abatement.
As a result, the most reliable solution in future production seems to be based on the route DR- EAF, and this is the solution investigated, at a pilot scale, in the frame of the HYDRA project.
The information reported here is collected from reference documents of the sector in which RINA-CSM has participated with active roles, as the reports referring to the European projects Project LowCarbonFuture & Green Steel for Europe, as well as publications available online from producer associations (EUROFER) and more generally from ‘stakeholders’ (ESTEP – European Steel TEchnological Platform, including producers, technology suppliers, R&D centres).