Inexperienced metal is hailed as the subsequent large factor in Australian business. Here is what the hype is about – Watts Up With That?
Jessica Allen, University of Newcastle and Tom Honeyands, University of Newcastle
Steel is an important component of our modern world, from which everything from cutlery to bridges to wind turbines is made. But the way it’s made – with coal – is making climate change worse.
On average, almost two tons of carbon dioxide (CO₂) are emitted per ton of steel. This accounts for around 7% of global greenhouse gas emissions. Redeveloping steel production is clearly key to the earth’s low-carbon future.
Fortunately, a new path is emerging. So-called “green steel”, which is made from hydrogen instead of coal, offers Australia a great opportunity. It would boost our exports, offset inevitable job losses in the fossil fuel industry and go a long way in combating climate change.
Australia’s abundant and cheap wind and solar resources mean we are well positioned to produce the hydrogen a green steel industry needs. So let’s take a look at how green steel is made and what the challenges are.
Steels for change
Steel making requires stripping oxygen from iron ore to produce pure ferrous metal. In traditional steel production, this is done with coal or natural gas in a process that releases CO₂. In the production of green steel, hydrogen from renewable energy replaces fossil fuels.
Australia exports nearly 900 million tons of iron ore annually but produces only 5.5 million tons of steel. This gives us great capacities to ramp up steel production.
A report from the Grattan Institute last year found that if Australia accounted for about 6.5% of the global steel market, it could generate about A $ 65 billion in annual export sales and create 25,000 manufacturing jobs in Queensland and New South Wales.
Steel making is a complex process and is mainly accomplished through one of three processes. Each of them can, in theory, be adapted to produce green steel. We examine each process below.
Read more: Australia could fall apart under climate change. But there is a way to avoid it
1. Blast furnace
Around 70% of steel worldwide is produced using the blast furnace process.
As part of this process, processed coal (also known as coke) is used in the main body of the furnace. Among other things, it serves as a physical support structure for materials entering and exiting the furnace. It is also partially burned at the bottom of the furnace to generate both heat and carbon monoxide, which removes oxygen from iron ore and leaves metallic iron.
This coal-powered process leads to CO₂ emissions. It is possible to replace part of the carbon monoxide with hydrogen. The hydrogen can remove oxygen from the ore, producing water instead of CO₂. This requires renewable electricity to produce green hydrogen.
And hydrogen cannot replace carbon monoxide in a 1: 1 ratio. When using hydrogen, the blast furnace requires more external heat than the coal process in order to keep the temperature high.
More importantly, solid coal in the main body of the furnace cannot be replaced by hydrogen. Some alternatives have been developed in which biomass – a fuel developed from living organisms – is mixed with coal.
But the sustainable and true-to-scale procurement of biomass would be a challenge. And that process would likely still generate some fossil fuel emissions. To ensure that the process is “green”, these emissions would have to be recorded and stored – a technology that is currently expensive and has not yet been tested on a scale.
Read more: Australians want industry, and they want it to be green. Steel is the beginning
2. Recycled steel
Around 30% of the world’s steel is made from recycled steel. Steel has one of the highest recycling rates of any material.
Steel is mainly recycled in electric arc furnaces that run on electricity. Each ton of steel produced in this way causes around 0.4 tons of CO, mostly through emissions from the combustion of fossil fuels to generate electricity. If the electricity were generated from renewable sources, the CO₂ emissions would be greatly reduced.
But steel cannot be continuously recycled. After a while, undesirable elements such as copper, nickel and tin accumulate in the steel and reduce its quality. In addition, steel has a long service life and a low turnover rate. This means that recycled steel cannot meet all of the steel demand and some new steel has to be produced.
3. Directly reduced iron
Direct Reduced Iron (DRI) technology often uses methane gas to produce hydrogen and carbon monoxide, which are then used to convert iron ore into iron. This process still causes CO₂ emissions and requires more electricity than the blast furnace process. However, its overall emission intensity can be much lower.
The process currently accounts for less than 5% of production and offers the greatest opportunity to use green hydrogen.
Up to 70% of the hydrogen obtained from methane could be replaced by green hydrogen without having to modify the production process too much. However, work is underway to use 100% green hydrogen in this method.
Read more: For hydrogen to be really “clean”, it has to be produced with renewable energies, not with coal
Become a green steel superpower
The green steel transition will not happen overnight and significant challenges remain.
Inexpensive, large-scale green hydrogen and renewable electricity are needed. And even if green hydrogen is used, the blast furnace process will continue to require carbon capture and storage technologies to achieve net zero emissions – and for the time being DRI.
Private sector investment is required to create a global export industry. Australian governments also have an important role to play in building skills, retraining, funding research and coordinating land use planning.
Revolutionizing the Australian steel industry is a daunting task. But if we play our cards right, Australia can be a major player in the green manufacturing revolution.
Jessica Allen, Senior Lecturer and DECRA Fellow, University of Newcastle and Tom Honeyands, Director, Center for Ironmaking Materials Research, University of Newcastle
This article was republished by The Conversation under a Creative Commons license. Read the original article.
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