With steel production taking one of the top spots for the most environmentally polluting industries, this particular sector has faced constant pressure ever since the Paris Climate Agreement to be more compliant with climate change induced regulations. However with steel closely interlinked with core aspects of numerous infrastructure and manufacturing processes, simply declining steel production is unfeasible, so experts have turned to alternative solutions such as green steel.
Our steel industry experts sat down with us to divulge on some of the key trends and industry insights surrounding this topic, to provide clarity on the production of green steel and the challenges it faces. Continue reading to find out more.
The blast furnace and the electric arc furnace are the biggest producers of steel today and have been since the phasing out of the open-hearth furnaces in sixties and seventies. Both methods currently account for around 70% and 30% of global steel production respectively.
However, since the Paris Climate Agreement of 2015, the emphasis for new technology has turned to the reduction of CO2 emissions. Given that the Blast Furnace route accounts for 92% of CO2 emissions from the Steel sector, the development of ‘green DRI’, (iron pellets that are fed continuously into the EAF), have become a priority to steel producers.
Recently, in Sweden, a consortium claimed they produced the first fully ‘green steel’, which Volvo has since purchased to produce trucks from this steel. The whole process used electrical energy from hydroelectric, wind power or solar energy, and ‘green hydrogen’ was used to produce green DRI.
The recent spiralling energy costs, with regards to the electric arc furnace, have now placed the emphasis on reducing the kWh per tonne of steel. To this end, we have seen the introduction of various forms of scrap preheating techniques to save on the electrical energy required. An example being how Primetals’ next generation shaft furnace, the Quantum Electric Arc Furnace, has replaced Fuch’s seventies ‘shaft furnace’, and similarly, Tenova’s Consteel system, which also relies on preheated scrap being fed into the furnace by a conveyor.
The availability of hydrogen poses a challenge as its role in replacing natural gas and coal as the reductant during the process is essential, however, there is little hydrogen gas available on the market. Although there are many new hydrogen plants being built or in early planning stages, a majority of what is currently being produced is being consumed by the producers.
Carbon is an essential part of steelmaking, and the term ‘carbon free steelmaking’ is a complete misnomer, as, by definition, steel is an alloy of iron and carbon. Carbon is also used in the process to make foaming slag – another essential part of the steelmaking process when using the high-powered electric arc furnace and high levels of injected oxygen.
With the removal of this carbon source from such feed material as DRI (nominally >1.8% carbon) or pig iron from the blast furnace, (around 4% carbon), the electric arc furnace steelmaker faces a great challenge over the coming years.
Alternative carbon sources are being investigated such as the use of biomass materials. However, as previously stated, when the steelmaker is looking to reduce electrical energy consumption, there is little doubt that with 0% Carbon DRI, the chemical energy that is generated by oxygen and carbon will be removed and electrical energy consumption will increase.
There are many ongoing projects throughout the world where global steel producers are looking to replace blast furnaces with electric arc furnaces, which will utilise renewable electrical energy, fed by green DRI. However there remains numerous obstacles to achieving this goal, not least the lack of renewable energy; in Europe there are far too few wind farms, solar energy and nuclear power plants. Hydrogen produced from a nuclear source is called ‘pink hydrogen’, remains a topic that will also always provoke debate in this area.
As mentioned earlier, the availability of hydrogen will also hinder advancement until hydrogen is available at a cost that is acceptable to the steelmaker, but the cost to produce green steel will certainly be higher.
Engage with a Pangea SI Green Steel Expert to help you overcome challenges and achieve high project standards.