The article “How green steel made with electricity could clean up a dirty industry" by Crownhart (2022) discusses Boston Metal’s new approach in manufacturing emission-free steel, known as green steel, with a pilot reactor, to combat the rapidly rising carbon dioxide emissions that are currently produced by the steel industry. Boston Metal’s current challenge is to scale up its production, to keep up with the increasing demands in the industry, as steel is used in almost everything, from machinery to construction. Two of the methods to produce green steel are known as molten oxide electrolysis (MOE) and direct reduction. During MOE, electricity is run through a cell containing a mixture of dissolved iron oxides and other oxides and materials, in order to drive the removal of oxygen from steel by heating the cells up to about 1600°C, thus emitting oxygen instead of carbon dioxide. For direct reduction, carbon dioxide is released when natural gas reacts with solid iron ore, to yield iron. When hydrogen is used in place of natural gas, the process is referred to as hydrogen direct reduction, where water vapor is emitted instead of carbon dioxide as stated by Crownhart (2022). Thus, green steel has been cited as a solution to reduce the steel industry’s climate impact.
However, green steel is currently not a viable option in replacing traditional steel presently due to the production methods’ dependence on electricity, which in turn relies on fossil fuels. The production cost of green steel is also higher as compared to traditional steel.
As fossil fuels are required in the production of electricity, the processes of making green steel still emit carbon at a large rate, regardless of how efficient the steelmaking process is. Despite green steel being marketed as a solution to decarbonising the steel industry, Gordon (2023) states that a notable amount of electricity is still required to produce green steel, as both hydrogen direct reduction and MOE require the use of tremendous amounts of electricity to produce green steel.
Blank (2019) outlines that 2,633 kilowatt-hours (kWh) of power are required to generate hydrogen for every one ton of crude steel produced from iron ore. Additionally, 816 kWh are required for the direct reduction process itself and running the electric arc furnace (EAF) plants. This means that for every ton of green steel produced, 1,713 kilograms of carbon dioxide are released into the air. In comparison, traditional steel made in a blast furnace emits 1,714 kilograms of carbon dioxide. This indicates that the difference in carbon emissions between the production of green steel and traditional steel is similar.
Furthermore, as reported by Gordon (2023), the electricity needed for the green processes must be "must-run" electricity - meaning that electrical generation must continue to operate, even during times of low demand or excess generation because it is deemed necessary for the stability and dependability of the power system. While there is renewable electricity available for the manufacturing of green steel, which would make green steel purely carbon-emission free, there is limited space for wind turbines and solar farms presently. A large demand for renewable electricity coming from many industries, including the steel industry, will make it unlikely that technological developments in renewable energy will be accessible in time to maintain present levels of steel production while achieving zero carbon emissions.
Producing green steel is more expensive than producing traditional steel. According to Gordon (2023), this is because of the scarcity of hydrogen and the limited availability of renewable energy sources. Though there is variance in price per ton of steel, the market price for traditional steel is $550 per ton. In comparison, steel made through hydrogen direct reduction costs about 20 to 30% more as stated by Blank (2019). According to Lea (2022), the cost of green steel needs to be reduced to below $2 per kilogram, ideally around $1 per kilogram, in order to be competitive with traditional steel production prices. Currently, the carbon taxes on green steel are at $90 per ton, making it not cost-competitive with traditional steel and would have to be raised by 33% to $120 per ton in order for green steel to be cost-competitive. Increasing carbon taxes can make traditional steel more expensive to produce because it generates more carbon emissions, thus making green steel more cost-competitive and encouraging producers and consumers to choose the more sustainable option.
Although green steel production has its drawbacks, it also offers advantages. According to Crownhart (2022), green steel production, in particular MOE, is more versatile compared to traditional steel-making processes.MOE allows for the use of a broader range of starting materials. In comparison, traditional steel-making in a blast furnace requires high-quality ore in order to produce high quality steel.
In conclusion, while green steel is marketed as a solution to decarbonising the steel industry, the reality is that it still requires a significant amount of electricity to produce. The processes of making green steel still emit carbon, as fossil fuels are needed to produce the electricity. Additionally, the production cost of green steel is higher than traditional steel due to the limited availability of renewable energy sources and the scarcity of hydrogen. Although green steel represents progress in reducing the carbon footprint of the steel industry, there is still much work to be done in terms of finding cost-effective, low-carbon solutions for the production of steel.
References:
Crownhart, C. (2022, June 28). How green steel made with electricity could clean up a dirty industry. MIT Technology Review.
https://www.technologyreview.com/2022/06/28/1055027/green-steel-electricity-boston-metal/
Lea, A. (2022, June 10). Green steel needs hydrogen price below $2/kg. Commodity & Energy Price Benchmarks.
https://www.argusmedia.com/en/news/2340240-green-steel-needs-hydrogen-price-below-2kg
Gordon, O. (2023, January 20). The four-horse race to decarbonise steel. Energy Monitor.
https://www.energymonitor.ai/sectors/industry/the-four-horse-race-to-decarbonise-steel
Blank, T. K. (2019, September). The Disruptive Potential of Green Steel. Rocky Mountain Institute.
https://rmi.org/wp-content/uploads/2019/09/green-steel-insight-brief.pdf