Green Steel: Decarbonising with Hydrogen-Fueled Production
As the fight against climate change ramps up worldwide, the need for industries and economies to respond is immediate.
Of course, different sectors contribute different amounts of greenhouse gas (GHG) emissions, and face different paths to decarbonisation as a result. One massive player? Steel and iron manufacturing, where energy-related emissions account for roughly 6.1% of global emissions.
The following infographic by AFRY highlights the need for steel manufacturing to evolve and decarbonise, and how hydrogen can play a vital role in the “green” steel revolution.
The Modern Steel Production Landscape
Globally, crude steel production totalled 1,951 million tonnes (Mt) in 2021.
This production is spread all over the world, including India, Japan, and the U.S., with the vast majority (1,033 million tonnes) concentrated in China.
But despite being produced in many different places globally, only two main methods of steel production have been honed and utilised over time—electric arc furnace (EAF) and blast furnace basic oxygen furnace (BF-BOF) production.
Both methods traditionally use fossil fuels, and in 2019 contributed 3.6 Gt of carbon dioxide (CO2) emissions:
| Steel Production Method | Materials Utilised | CO2 Emissions (2019) |
|---|---|---|
| EAF | Scrap | 0.5 Gt |
| BF-BOF | Scrap, iron ore, coke | 3.1 Gt |
That’s why one of the main ways the steel industry can decarbonise is through the replacement of fossil fuels.
Hydrogen’s Role in Green Steel Production
Of course, one of the biggest challenges facing the industry is how to decarbonise and produce “green” steel in an extremely competitive market.
As a globally-traded good with fine cost margins, steel production has been associated with major geopolitical issues, including trade disputes and tariffs. But because of climate change, there is also a sudden and massive demand for carbon-friendly production.
And that’s where hydrogen plays a key role. Steel traditionally made in a blast furnace uses coke—a high-carbon fuel made by heating coal without air—as a fuel source to heat iron ore pellets and liquify the pure iron component. This expels a lot of emissions in order to get the iron hot enough to melt (1,200 °C) and be mixed with scrap and made into steel.
The green steel method instead uses hydrogen to reduce the iron pellets into sponge iron, metallic iron that can then be processed to form steel. This process is also done at high temperature but below the melting point of iron (800 – 1,200 °C), saving energy costs.
And by introducing non-fossil fuels to create iron pellets and renewable electricity to turn the sponge iron and scrap into steel, fossil fuels can be removed from the process, significantly reducing emissions as a result.
The Future of Green Steel Production
Given the massive global demand for steel, the need for hydrogen and renewable energy required for green steel production is just as significant.
According to AFRY and the International Renewable Energy Agency, meeting global steel production in 2021 using the green steel method would require 97.6 million tonnes of hydrogen.
And for a truly carbon-free transition to green steel, the energy industry will also need to focus on green hydrogen production using electrolysis. Unlike methods which burn natural gas to release hydrogen, electrolysis entails the splitting of water (H2O) into oxygen and hydrogen using renewable energy sources.
Full green steel production would therefore use green hydrogen, electrolysers running on renewables, and additional renewables for all parts of the supply chain:
| Steel Production Source | Annual Steel Production | Green Hydrogen Required | Electrolyser Capacity Required | Total Renewables Capacity Required |
|---|---|---|---|---|
| Base Reference | 1 Mt | 50 kT | 0.56 GW | 0.7 GW |
| U.S. | 85.8 Mt | 4.3 Mt | 48 GW | 60 GW |
| Europe | 103 Mt | 5.2 Mt | 58 GW | 72 GW |
| China | 1032.8 Mt | 51.6 Mt | 581 GW | 726 GW |
| Global | 1951 Mt | 97.6 Mt | 1,097 GW | 1,371 GW |
Currently, green hydrogen production costs are higher than traditional fossil fuel methods, and are dependent on the levelised costs of renewable energy sources. This means they vary by region, but also that they will reduce as production capacity and subsidies for renewables and green hydrogen increase.
And many major European steel manufacturers are already leading the way with pilot and large scale facilities for green steel production. Germany alone has at least seven projects in the works, including by ArcelorMittal and ThyssenKrupp, two of the world’s 10 largest steelmakers by revenue.
AFRY is a thought leadership firm that provides companies with advisory services and sustainable solutions, in their efforts to fight climate change and lead them towards a greater future.
