Steel will remain essential for the transition to a greener future. So decarbonising the manufacturing process of this key material for many renewable energy technologies is vital for reducing CO2 emissions from supply chains.
Achieving net zero greenhouse gas (GHG) emissions by mid-century is one of the most important challenges of our time. It's an undertaking of unprecedented scale, involving every major sector of society, and requiring nothing less than a complete transformation of the way we produce, transport, and consume energy and goods.
The rapid deployment of clean energy technologies to improve energy efficiency is at the heart of the net zero transition plans described by the International Energy Agency. Under these plans, increased investment in clean energy will eliminate the need for new conventional energy projects. But some energy suppliers argue that this is not the only way to get to net zero by 2050. More efficient emission reduction technologies, the introduction of sustainable energy sources, and adjustments to the energy consumption mix will also have an impact.
Steel will be indispensable in many areas.
Today the steel industry is a significant contributor to GHG emissions, particularly carbon dioxide (CO2). Producing iron and steel uses carbon-intensive fuels like coal and natural gas, which create the very high temperatures required to melt the raw materials. Given that steel will continue to be needed to support the green transition, sustainable energy companies are working with steel producers to develop low-carbon steel and thus reduce emissions.
This isn't an easy task. Average global CO2 emission intensities have been rising, largely due to increased steel production in China and India. On average, the CO2 emission intensity of global crude steel production is about 1.8 to 2.0 ton of CO2 per ton of steel produced. To put this in perspective, about 85 average cars driving 100 km each would collectively emit 1 ton of CO2.
However, steel industry emissions are heavily dependent on the technology employed. The blast furnace-basic oxygen furnace (BF-BOF) is the traditional method for heating iron ore to produce steel. This system mainly uses coking coal as an input material, with emissions typically around 2 ton of CO2 per ton of steel.
The electric arc furnace (EAF) uses electricity to melt mainly recycled steel scrap, producing a smaller carbon footprint compared to the BF-BOF system. Emissions are between 0.4 and 0.7 ton of CO2 per ton of steel produced. These outputs can be considerably lower if renewable energy is used.
More than 70 % of the world's steel is produced using the BF-BOF system, with the other 30 % employing the EAF method. The split varies between regions, with China and India both using BF-BOF for 90 % of their output. Many countries in Asia have ample reserves of iron ore and coal, making this system more economically viable here. In the Middle East, the abundant and relatively cheap natural gas used to generate electricity makes the EAF method more competitive. In Africa, significant hydroelectric power resources also make EAF more attractive.
To help meet the ambitious targets to reduce carbon emission intensity by mid-century, several promising decarbonisation technologies are being developed within the steel industry. These include:
Recycling and the circular economy: Recycling steel scrap using EAF plants requires less energy and emits less CO2 than primary BF-BOF steel production. Optimising production processes, improving heat recovery systems, and integrating advanced control systems to minimise energy waste can all contribute to reduced emissions.
These technologies are at various stages of development, and widespread adoption will require further research, investment, and policy support.
Steel plays a crucial role in the energy transition. It is used extensively in the construction of renewable energy infrastructure, including wind turbines, solar power systems, and hydropower facilities. Steel is essential for the transmission and distribution of electricity, particularly across long distances, and is a key element in electric vehicle manufacturing and the charging infrastructure. It is also required for CCS and hydrogen capture facilities, including pipelines and storage tanks.
So far steel has only been seen as part of the GHG emissions problem. But it can also be part of the solution. And since many renewable energy projects currently cannot be delivered without steel, it is important to decarbonise steel production as quickly and effectively as possible. This is an important and growing area of the new, green economy.
