April 14, 2025

expert reaction to the Scunthorpe British Steel factory situation

Scientists comment on the British Steel factory situation.

 Prof David Dye, Professor of Metallurgy, Imperial College London, said:

How do the furnaces work? And why do we need these certain ores/materials to keep them running? Why are they so difficult to switch back on if they turn off?  Why is it crucial that they need to mobilise these supplies of fuel etc. What can the government do if they turn cold?

“Roughly speaking, it’s a big counterflow reactor; throw in sintered iron ore and coke in the top. The iron oxide gets reduced progressively to iron by carbon monoxide as it gets hotter and hotter, the carbon monoxide being generated by burning the coke (carbon) in air in the bottom of the blast furnace. The ‘blast’ is the injection of pressurised air in the bottom. The peak temperature is over 1900C, and the molten iron tapped is over 1400C; this dribbles down over the bed of coke; the structural integrity of the coke is a major issue in design of the reactor.  So a blast furnace is essentially a big brick-lined, custom-shaped chimney containing a big pile of reacting chemicals containing a solid-liquid-gas reaction mixture.  That is, it’s complicated!

“So: it’s a tricky exercise to change the conditions it’s operating in; it’s not like throwing a switch.  You can (and by all reports they are) run it at a lowered rate, but there are limits.  It is possible of course to relight a blast furnace. Campaign lifetimes have increased over the decades and are now 20+ years – see link for example. Typically, a big integrated steelworks has/had several blast furnaces (4 at Scunthorpe) so that one could be down for an 18-month refurbishment cycle, e.g. in the 1960s they might have been under 10 years in duration and so the refurbishment team would be semi-continuously cycling around them. These life extensions to plants are part of why a steelworks now employs so few people compared to the 1970s or 1980s, and indeed a lot of the plant upgrades are now contracted out to the equipment manufacturers.  So: relight is usually accompanied by a £200m+ refurbishment, replacement of the refractory brick and so on. Our knowledge of how the coke bed behaves in the hearth, sitting on top of the molten iron and slag, is incomplete (https://doi.org/10.3390/pr8111335). 

“That is, anything is possible if you are willing to spend enough money and time, but furloughing a blast furnace for months or a year isn’t normally considered a viable response to swing in the market price of steel; and this is why oversupply and dumping are such a big issue for the industry (similar for aluminium pot lines); you end up having to produce at a loss.”

What are the next steps now that the Government has stepped in and how ministers can protect the industry while still transitioning to net zero?

“Difficult to say. Historically when the industry was nationalised, the Treasury focus on manning levels to minimise benefits claims and the minimisation of public sector debt meant that the industry wasn’t permitted to invest and innovate to keep pace with technological improvements and its productivity position became more and more unviable relative to European competition. There’s also a state aid angle. Tata are investing several £bn in (a really impressive) modernisation of the Port Talbot site to accompany the governments investment so that when the EAFs are completed in a couple of years time they hope to be in a better competitive position than was the case in the past.  Is it possible for something similar to be done at the Scunthorpe site? Well, thats a multi-£bn question, isn’t it?  More than anything else, it will depend on the ability to bring together the investment coalition, engineering skillsets and customer pipeline to make a viable business, in competition with other regional (steel is mostly regional) steelmaking sites in northern France, Germany, Belgium and the Netherlands.”

Net zero and the proposed Cumbria coal mine:

Some basic points;

“1. Net zero is a target legislated for in 2019 by the Johnson administration (The Climate Change Act 2008 (2050 Target Amendment) Order 2019 – see link).  That the Tory party has changed its mind and is now campaigning against its former policy is, well, interesting. It’s difficult to make long-term (multi-decade) investment decisions when the policy environment is so changeable.

“2. The proposed Cumbria coal mine is irrelevant to this discussion. The coal that is moved by ship to Port Talbot or the Humber estuary can come from anywhere in the world, and, were the Cumbria mine to have been given permits to build, would be at the world market price; there is a large fungible market in seaborne metallurgical coke and shipping costs are very low. In any case the coke price isn’t an enormous input to the cost of raw blast furnace iron used in steelmaking.

“3. The amount of scrap steel arising for remelting in the UK is, as yet, more-or-less unchanged by the transition to EAFs. Similarly, local, regional and global demand for steel is largely unaffected. And even small cost increases from EU/UK carbon taxes or import tariffs won’t, at currently mooted levels, have much effect on global demand from construction or automotive (or other, smaller uses) either. That is, moving to EAFs and using scrap locally rather than shipping the scrap to China and making iron in blast furnaces here, doesn’t change the amount of scrap recycled or blast furnace iron produced – it just moves the emissions around.  OK, there are caveats to this – Chinese blast furnaces are often very modern and can be more efficient that the ones we are scrapping.  But, the carbon content of the electricity isn’t a big drive here because remelting uses much less energy than making new iron, so the dominating factor is the blast furnace iron production.

“4.  Deindustrialising the UK has, as UK Steel and others have argued, been a reasonably big driver for UK emissions reductions, and reductions in blast furnace steelmaking and fertiliser production have contributed big chunks of that. So we are doing well at decarbonising, but the cost is closing down our energy- and emissions-intensive industries.

“5. Hydrogen-based direct reduced ironmaking (H-DRI) looks like the most likely route to carbon-free ironmaking, today. In Sweden and Finland, there are big investments being made to make this happen. Using hydrogen derived from steam methane reforming isn’t that attractive from an emissions perspective, although stuffing the CO2 produced back into Norwegian gas wells (as an enhanced oil recovery measure) might change that logic – good for Equinor/Norway. But unless the proposed EU Carbon Boarder Adjustment Mechanism comes to pass it will likely be cheaper to import iron (Hot Briquetted Iron) from places without carbon taxes, eg India, China, Australia, Qatar, Russia, etc.   Some trading of iron does in fact already happen. Electrolyser hydrogen production looks tantalising but, as Michael Liebreich ’s hydrogen ladder shows (link) there are existing hydrogen-using processes like fertiliser production that it would be attractive to demonstrate that on first – that is, to use hydrogen as a vector for decarbonisation, we first need to decarbonise hydrogen. That is, it doesn’t look like H-DRI is coming quickly enough to be a solution for the UK, which is why Tata went down the road it went down at Port Talbot.

“6. As a customer for the sorts of high integrity steels used in bearings and for aerospace and defence, I’ve participated in lots of discussions about if we could cope without blast furnaces and retain UK strategic autonomy. As I say, it’s possible to buy 50-tonne mild steel slab on the open market and in Europe to remelt into ladle furnaces and VIMs in Stocksbridge and Rotherham, as at present, so I’m not too worried. Globally, the stock of steel is increasing, so even as copper accumulates in the stock of scrap there will continue to be a need for new ironmaking from ore, so I’m not too worried about speciality steels from a global perceptive either. There is also work ongoing on recovering copper from molten iron and other adjustments to the refining process flowchart. But, it would be an adjustment, for sure.”

John Patsavellas, member of the Institution of Engineering and Technology’s (IET) Sustainability and Net Zero Policy Centre; Professor Mark Jolly of Cranfield University; and Professor John Loughhead CB OBE CEng, Fellow and energy expert at the Institution of Engineering and Technology (IET), said:

What is a blast furnace?

“John Patsavellas, member of the Institution of Engineering and Technology’s (IET) Sustainability and Net Zero Policy Centre, in conjunction with Professor Mark Jolly of Cranfield University said: “Blast furnaces reach temperature of more than 1,700 degrees Celsius for smelting iron. Iron ore, coke and limestone are melted: the ore provides the iron, while the coke acts as fuel and a reducing agent that imparts carbon into the iron, reducing its melting point and, coupled with the limestone, removes its impurities. These removed impurities then form slag, a glassy residue which can be used to make cement.

“This process reduces iron oxide into iron using carbon monoxide generated by the coke; it’s therefore important to have the right type of ore and coke to ensure high quality steel is produced with a minimal amount of slag and ensuring low energy use. Lower quality materials will lead to higher energy consumption, higher emissions, and higher costs to make a lower quality product.”

Can we just turn it off and turn it on again?

“Professor John Loughhead CB OBE CEng, Fellow and energy expert at the Institution of Engineering and Technology (IET), added: “If the furnace cools, the slag will solidify into a hard substance and block the furnace, so would need to be removed mechanically, which itself can damage the furnace. We need to maintain these supplies of materials to keep the furnaces running and stop them getting cold. We need to use a particular type of coal, coking coal, to make steel.”

“Prof Patsavellas explained: “Blast furnaces are designed to run continuously for their 10–20-year lifecycle, with just the occasional re-linings needed for maintenance. If a furnace cools down, the brick linings and refractory materials – including bricks in the furnace – may crack due to the changing temperature, leading to an expensive and time-consuming process to complete the repairs and make them useable again.

“Restarting a cooled furnace can take months, involving a lot of hot, dirty, and risky work that will be very expensive and is entirely avoidable. You’re essentially looking at a complete rebuild of the inside of the furnace. Maintaining a continuous supply of fuel, ore and power is therefore essential to our national steel capability to ensure industrial resilience.

“The steel-making process has been optimised around the use of specific materials, which needs to be maintained to keep the high quality. Using other materials or lower quality ones can make the economics of the plant not viable.”

What happens next?

“Prof Loughhead commented: “Protecting the plant will mean we need to assure a market price at a rate that Scunthorpe can achieve. To do this while achieving net zero ambitions will mean either supporting carbon capture and storage developments at the plant, or moving to reprocessing scrap metal with electric furnaces; the latter does not produce high quality ‘virgin’ steel though, so we’d still be reliant on imports.

“High electricity costs in the UK, coupled with carbon pricing, mean the plant incurs high running costs, which hinders its ability to be competitive on the export market. A reduced market for the product then makes it hard to achieve efficiencies through volume.”

“Prof Patsavellas continued: “Keeping the blast furnaces going at Scunthorpe should be a temporary measure to maintain the production of high quality ‘virgin’ steel in the UK. This is essential for a number of industries, mainly defence and infrastructure.

“We also need to invest in developing the new technology of direct reduction of steel, which uses hydrogen or ammonia to cut out the interim stage of using pig iron with high carbon which then has to be reduced in the refining process using oxygen. Both the blast furnace and the refining stages produce huge amounts of CO2, while direct reduction avoids this; the challenge with it at the moment is the supply and cost of the chosen reducing gas. Research into this technique is underway at the Materials Processing Institute.

“The coke from the Cumbrian coal mine was never of the quality high enough for the Scunthorpe plant; it was destined to be exported for processes in other parts of the world, which would have increased global carbon emissions.”

Commenting on the energy policy/net zero implications:

 Prof Vlad Mykhnenko, Professor of Geography and Political Economy, University of Oxford, said:

“The progressing nationalisation of the British steel industry will have a tremendous impact upon the UK’s as well as wider European net zero transition plans.

“The steel industry is responsible for around 7% to 8% of the global CO2emissions; hence the decarbonisation of this sector plays a key role in achieving the UK’s as well as the European Union’s ambitious climate goals. Both the UK and the EU have committed to moving towards low- and zero-emission steel, also known as ‘green steel. For 2030, the EU producers are tasked with reducing their green-house gas emissions by at least 30%, with a near-zero emission target set for 2050. In the UK, the government has targeted a 95% emission reduction from steelmaking by 2050. 

“In order to facilitate and speed up this transition, the EU will use a Carbon Border Adjustment Mechanism (CBAM) – a carbon tariff on carbon intensive products, such as steel, cement and some electricity, imported to the European Union. Legislated as part of the European Green Deal, it takes effect in 2026. Similarly, the UK Carbon Border Adjustment Mechanism (CBAM) will be introduced on 1st January 2027.

“Carbon import tariffs, combined with increased internal tax pressure on domestic CO2 polluting industries, will eventually make traditional carbon-intensive steel-making unprofitable. In this context, blast furnaces currently operating at the British Steel works in Scunthorpe, Lincolnshire, will have to be phased out.

“Gradually, but sooner than later, the traditional furnaces that use coking coal for energy fuel will be replaced by electric arc furnaces that use renewable energy-sourced electricity for fuel. In the long-run, it is believed that green, i.e., renewable energy-sourced, hydrogen will be used for fuel in steelmaking.

“Whilst the investment needs for steelmaking facilities’ conversion from coking coal-fuelled to ‘green’ steel production themselves are considerable; the bulk of future green steel investment actually lies in renewable energy generation. To implement its ambitious next-zero goals, the UK government will have to encourage and co-fund billions’ worth of new renewable energy generation capacity. Owing and controlling one’s domestic crude steel production, whilst imposing significant import tariffs on carbon-intensive goods, should significantly help the state in getting closer to the 2050 target.”

Dr Ed Atkins, Senior Lecturer, University of Bristol, said:

What asked to respond to claims that “Ed Miliband’s net zero policies” along with the Cumbria coal mine not being allowed, could be responsible for failure of steel industry

“Blaming net zero or the blocked coal mine at Whitehaven risks overlooking core issues affecting steel at Scunthorpe. These include older technologies, cheaper steel from elsewhere flooding the market, and soaring energy costs affecting industries across the UK.

“If done right, strategic green investment can actually provide a solution for workers at Scunthorpe as well as at Neath Port Talbot: investing in new technologies, subsidising new renewables to boost heavy industry, and supporting those workers affected by this transition.”

Prof Roger Kemp, Professor Emeritus, School of Engineering, Lancaster University, said:

The government is attempting to keep open the blast furnaces at Scunthorpe, for which various arguments have been made, including:  to maintain a strategic industry that would be needed for large scale rearmament;  to maintain jobs in a town with little other employment; to avoid imports, and improve the balance of payments. No mention has been made of the effects on climate change.

Blast furnaces use iron ore, coke and limestone – and a fierce blast of air (hence the name) – to convert the ore into steel. The coke is largely converted into carbon dioxide, that is discharged as hot gas through the top of the furnace.  Producing 1 tonne of steel results in the emission of about 2 tonnes of carbon dioxide.

Electric furnaces, as being installed in Port Talbot, are fed with scrap steel, so they are recycling existing steel, not making new “virgin” steel from iron ore.  Bloomberg have predicted steel demand to grow by 35% by 2050 so, even with the most efficient recycling processes, there will still be a need for virgin steel.  In the short term, the environmental question is not about the effect of keeping the Scunthorpe blast furnaces on overall carbon dioxide emissions, but whether the emissions will emanate from the UK or from another country.

Longer term, virgin steel can be produced using a hydrogen process, which emits water vapour, H2O, not carbon dioxide, CO2.  But this has to be integrated into a wider hydrogen infrastructure which, at present, is in early formative stages in the UK.  Like recycling using arc furnaces, hydrogen reduction uses fewer workers than do blast furnaces, so it is not a long-term solution to maintaining mass employment in old steel towns.

Professor Sara Walker, Director, and Prof David Flynn, Co-Director, Hub on Hydrogen Integration for Accelerated Energy Transitions (HI-ACT), said:

“Steel-making is the largest industrial sector in the UK in terms of both energy demand and GHG emissions, and up to 75% of energy demand in steel-making is for coke in the blast furnace at factories like Scunthorpe [Griffin and Hammond, 2021]. Steel is used in an extremely wide variety of end use sectors, including construction, defence, manufacturing, and transportation. Globally, the sector is exploring ways to transition towards cleaner, lower-emission methods to create steel. This includes direct ore reduction, which replaces the need for blast furnaces by using hydrogen to reduce the iron ore into iron, and electric arc furnaces which can re-process scrap steel.

“In the UK, research has been undertaken to improve the efficiency of blast furnaces, which need to reach very high temperatures. More work is needed, to consider how to reduce emissions from steel-making, perhaps through carbon capture, the use of biomass, the use of hydrogen, and electrification. This decarbonisation of the steel-making process is vital, given the expected global demand for green steel will grow significantly from 2040 onwards.

“Birmingham and Glasgow are part of the Hub on Hydrogen Integration for Accelerated Energy Transitions, and we are considering likely pathways for industries such as steel-making to move away from emissions-heavy fossil fuels, and look at options for electrification and hydrogen. The challenges of the Scunthorpe Steel works provides a magnifying lens to the importance of coupling sustainable and low-cost energy for UK critical national infrastructure. The security of supply concerns reinforce the importance of our HI-ACT objectives towards securing more sustainable energy within the UK. Through intelligent coordination, since the free market cannot resolve this itself, the steel works represents a prime investment opportunity for hydrogen investment into the UK, offering a consistent, secure and high level of energy demand, for steel production which underpins multiple high growth and critical end use markets. In addition, such investments generate “overspill” benefits for neighbouring businesses and residential energy demand.

“Today, it’s forecasted that the U.K. will incur £1.4B of energy curtailment costs in 2025. HI-ACT is supporting stakeholders with objective and expertise analysis aligned to accelerating whole system hydrogen integration for diverse end use markets. Unlocking the potential of the UK’s energy technologies and infrastructure, could not only safeguard but ensure a competitive steel production baseline in the UK.”

Dr Abigail K Ackerman, Royal Academy of Engineering Research Fellow, Department of Materials, Imperial College London, said:

“The steel industry currently accounts for around 15% of global industrial CO2 emissions. Within the UK, steel plants such as Scunthorpe account for amount 6-7% of total CO2 emissions. Nationalisation could mean a faster implementation of green technologies such as hydrogen based steelmaking and electric arc furnaces, with potential for retraining within the sector towards green based technologies. There is also the opportunity for easier integration within the national grid of these technologies, and using lower emission steel within the UK’s infrastructure, such as railways. However, this transition is expensive and will require investment into new technologies and infrastructure by the government.

“Nationalisation could accelerate the government’s plans for the net zero transition, provided there is investment in new technology and infrastructure, including with the national grid to provide the energy required, and a transition plan for workers to ensure there is still employment for them within these sectors.”

Commenting on the engineering aspects of the situation:

Dr Julian Steer, a Research Fellow from Cardiff University’s School of Engineering, said:

How hot do the blast furnaces get? How do the blast furnaces work? And why do we need these certain ores/materials to keep them running? 

“The hottest part of the furnace can get to temperatures of up to 2200°C; the blast furnace converts Iron Oxide, supplied as Iron ore, to Iron by a counter current chemical reduction reaction where raw materials descend through the furnace as hot gases rise up through the furnace.  The blast furnace is a very well optimized process that requires the reactions to occur at an even rate throughout the process.  To do this, raw materials are selected based on the properties needed to produce iron continuously and efficiently.”

Why are the blast furnaces so difficult to switch back on if they turn off? 

“The size, dimensions, and complex reactions in the blast furnace mean that heat distribution and heat transfer through the furnace are absolutely critical to stable iron production.  Raw materials are continuously added to the top of the furnace as hot molten iron is continuously tapped from the bottom, the shear scale of this process means that the distribution of the heat through the furnace is critical at all times.”

Why is it crucial that they need to mobilise these supplies of fuel etc.?

“The production efficiency and stability of the whole process of iron production requires careful raw material selection to maintain consistent, and uniform reactions through the furnace and process.”

What can the government do if these blast furnace turn cold? 

“If the furnace goes cold, the molten materials inside become solid, blocking the furnace and making any form of restart very difficult, costly and potentially terminally damaging to the furnace.”

Dr Abigail K Ackerman, Royal Academy of Engineering Research Fellow, Department of Materials, Imperial College London, said:

Blast Furnace Operation:

“A blast furnace is used to convert iron ore (hematite, Fe2O3) to pig iron (Fe) by mixing it with coke (carbon), limestone and hot air.

“Limestone is used to remove impurities, forming slag which is a waste material. The slag collects  impurities, primarily silica, and is removed and used in construction materials like cement.

“The coke, which is a derivative of coal, reacts with the hot air, which is blown in at the bottom of the furnace at around 1000degC, and forms carbon monoxide (CO). The carbon monoxide reacts with the iron ore to produce molten iron and CO2, which is released as gas.

“The resultant molten liquid iron ore is tapped out at the bottom of the furnace, and is referred to as pig iron.”

Blast Furnace Temperatures:

“Blast furnaces have ‘heat zones’ in order to drive the different chemical reactions which occur within the furnaces. They are set up in a large chimney like structure and have 3 main zones:

“Top (throat) – 200degC to 600degC – Raw materials are poured in

“Middle (Stack) – 600degC to 1200degC – Iron ore starts to reduce forming gases (mainly CO) and the initial reduction of iron ore occurs. The initial reaction has the iron ore (Fe2O3) eventually reducing to FeO. 

“Middle (Bosh) – 1200degC to 1600degC – The main chemical reaction occurs, where FeO reduced to Fe. The slag forms here, where limestone reacts with impurities.

“Bottom (Hearth) – up to 2000degC – Hot air (1000degC to 1200degC) is blown in at the bottom of the furnace, which causes the coke to combust and release heat and CO2.

“The molten iron and slag are collected. The slag is lighter that the molten iron so is floats on top of it and can be collected by tapping, or drilling a hole, above the molten iron and allowing the slag to flow out..

“The molten pig iron is removed by tapping, or drilling, a hole in the bottom of the furnace, and flows through guide channels to be collected and transferred to a basic oxygen furnace (BOF) to mix with carbon and make steel.

“Tap holes are made roughly every couple of hours, and then plugged back up with a clay mixture to contain the heat and molten materials in the furnace.

Essential Materials:

“Coking coal, iron ore and limestone are essential to keep the blast furnaces in Scunthorpe running, and these are the critical raw materials that are being sourced. Without these materials in the correct amounts, the chemical reaction will be disrupted and the furnace will cool as the chemical reaction absorbs heat, which is provided by the burning of coke.”

Why can’t you let it go cold?

“The high temperature of the blast furnace means the iron and slag are molten at the bottom, they are in liquid form at around 1500degC. If the furnace is allowed to cool, these materials solidify and can stick to the interior of the furnace. When the metal cools it contracts, which can cause the lining of the furnace to become damaged resulting in expensive repairs to the furnace interior before it can be heated up again.

“Additionally, blast furnaces have various inlets and outlets for pumping in hot air and extracting the molten material. When this solidifies, these can become blocked and are extremely difficult and costly to fix.

“The chemical reaction is disrupted when the furnace goes cold, and restarting this reaction can be complicated due to the heat required to melt the solicited materials, and the balance of gas and materials needed to obtain the correct chemical reaction.

“Finally, a large amount of fuel is required to restart a furnace, which is costly, and it can take anything from days to weeks to get the furnace back up to temperature and getting the correct chemical reaction to occur. It takes much more energy to melt the materials back down than to keep them at temperature. And, of course, there’s a loss of production which costs money.”

Why is it crucial to keep the Scunthorpe furnaces running?

“The Scunthorpe blast furnaces are the last remaining blast furnaces operating in the UK, and therefore the only method for the UK to produce ‘virgin’ steel, which is steel that has not been used in any other process. Other steel producers in the UK, such as TATA, have moved to using recycled steel and electric arc furnaces (EAF). Without the Scunthorpe plant, there will be an impact of the supply chain of steel to essential services such as construction, rail and defence. There will also be an impact on the Scunthorpe community, with a loss of work for the many steelworkers.”

What can the Government do if they turn cold?

“If the furnaces go cold, the options are to restart the furnaces, which will be more costly that obtaining the raw materials required to continue steel production due to the damage that will occur within the furnace from the solidification of the iron and slag, and the large amount of energy required to restart the furnaces.

“The government can choose to change the type of steel production to, for example, recycled steel using EAFs, like Port Talbot, however this will most likely result in job losses, economic impact on the people of Scunthorpe and the UK economy, and significant disruption to the UK supply chain. There is also not enough scrap steel to supply EAFs, so primary virgin steel will need to be sourced from elsewhere. The National Grid is also not set up to supply the energy required to fuel EAFs at this scale so it would be a timely and costly option.

“There is also the option to start producing green steel, which uses hydrogen as a reduction agent rather than coal based coke. However, this requires a large amount of hydrogen and the UK hydrogen economy is not set up for this scale of production currently. Nevertheless, this is the best option for long term CO2 goals.

“Finally, there is the option to close British Steel. This would again have a significant impact on the UK economy, supply chain and the local area. The loss of steel sovereignty could impact the supply chain in the long run as there would be an increased dependence on external steel suppliers, which is impacted by geopolitics.”

Prof Barbara Rossi, Associate Professor of Engineering Science, University of Oxford, said:

“Steel is the most commonly used metal in the world. Blast furnaces and electric arc furnaces are present everywhere, all over the world. There is worldwide 1.9 billion tonnes of crude steel produced per annum. UK in 2020 (then still a EU member state) was the 8th largest steel producer in the European union, which produced in total >150 million tonnes of steel in 2019, only 8% of the world total. Japan alone produced roughly 100 million tonnes, while the biggest steel producing country is currently China, which accounted for above 50% of world steel production in 2020. Globally, the steel industry emits 25% of all industrial greenhouse gases, which is more than any other industrial sector.

“The construction sector is the largest steel using sector and that is not likely to change. It accounts for more than 50% of the world steel demand, with the other major uses being the manufacture of vehicles, industrial equipment and final goods. The global population is forecast to increase to more than 9 billion people over the next 40 years. The population growth rate in Europe (and the UK) is only expected to start decreasing slightly by 2050. And, by then, about 75% will live in cities (~50% today). We still have to build the buildings and infrastructures for these cities and replace those that are damaged. When our country needs more and more new homes, new buildings, new infrastructure, we will have to go higher, more slender and leaner in dense populated areas and the need for ultra-strong and highly ductile materials like steel will become increasingly pressing.

“Steel is indefinitely recyclable, and, while it is recycled, it does not lose its performance which is an extraordinary ability inexplicably often ignored. It isn’t the case of most construction materials: other than steel, aluminium or stainless steel, you can only recycle glass indefinitely provided that you sort the type of glass appropriately. Steel is not just downcycled into a less noble material, just like an old jewel can be turned into a new one, steel can be melted over and over again.

“Recycled steel is one of the industry’s most important raw materials. We have accumulated almost 1 billion tonnes of steel only in the UK, all of which must be recycled, and, today, we generate about 10 million tonnes of scrap a year. Studies show that in the next 10-15 years, that availability of steel scrap will rise from 10 million to 20 million tonnes (global flow of steel scrap are likely to treble in the next 30 years) because all the steel made in the past will be recycled.  In 2018, in Europe, this exceeded 110 million tonnes, showing that there is no scrap shortage. Despite its weak position in the scene of steel production, this is one of the advantages by which the UK could profit in the current global change of steel production.

“We have already produced the steel that we will need tomorrow. With increased availability of scrap and under our nation’s commitment to cut its domestic emissions by 2050, we can anticipate a global shift from blast furnace to electric arc furnace production. Roughly 2/3 of today’s liquid steel is made from iron ore, with the rest made from scrap, but at present >50% of the scrap originates from the manufacturing process, rather than from end-of-life recuperation. This is even though (1) on average, steel products have an approximate life horizon of 35-40 years, before being scrapped, and (2), apart from ~10% of steel that is buried (e.g., oil pipes or in building foundations), most end-of-life steel can be easily collected for recycling. Even if the total demand for steel production will increase, one can demonstrate that if most old steel is recycled, future requirements could be met entirely through increased production from scrap via electric arc furnaces. In America today, >50% of all domestic steel demand is already made by recycling domestic scrap. And since steel recycling causes significantly less greenhouse gas emissions than blast furnaces (topped by the fact that the UK already produces low emissions electricity grid, with high potential for further improvement, so recycling steel in the UK today leads to a reduction in emissions of > 2/3 compared to global average primary steel), UK need for steel recycling can be expected to grow significantly and rapidly.  This will increase with more renewable generation capacity and will grow strategically important as global pressure to alleviate climate change increases.

“UK’s commitment to decarbonization need to address the emissions which are released from within UK borders. Although closing steel plants in the UK would lead to a reduction in the emissions, our future demand for steel may lead to higher global emissions if the emissions intensity in other countries is greater than that in the UK. Rather than providing extensive efforts in technologies allowing reduced emissions in primary production which require major capital investment, a more effective contribution to global mitigation would be to produce our domestic steel through electric arc furnaces combined with a massive decrease of their emissions which are directly linked to the emissions intensity of local electricity generation.

“There is nonetheless a technical limitation on the extent to which scrap can be substituted for iron ore: contaminants. Scrap composed of large pieces such as that from construction, have well controlled composition while scrap collecting from mixed waste streams have higher levels of contamination. The latter is usually sourced when scrap prices are high. As a consequence of contamination, the degree to which recycled steel can replace primary steel is capped by the inability of (a) imperfect control of metal composition in scrap steel collection and (b) today’s technologies to adjust the chemical composition of liquid steel produced with electric arc furnaces. Therefore, steel scrap supplies have to date been mostly absorbed by the lowest grade products (such as reinforcement bars). 

“It is possible to vaporise unwanted metal contaminants from liquid steel by vacuum arc re-melting. This is already a commercial strength in the UK and used for making some of the highest quality steels for e.g., aerospace components. The innovation opportunity is to replicate this success at higher speed and lower cost. Other processes than vacuum arc re-melting have been tested in research laboratories but were abandoned due to lack of economic incentive. The UK, with its high volumes of scrap and its commitment to act on climate mitigation is well placed to lead the development of these technologies.

“We cannot replace steel, it’s ridiculously cheap, ultra-strong and highly ductile, and completely recyclable, fitting into any story about a circular economy. Not a single construction material taken alone can compete with steel today.  But we can produce low carbon steel and build better structures, lasting longer, not harming our environment. If UK would recycle its own scrap to deliver high-quality steel satisfying its domestic demand in a closed loop it would lead to massive decrease of UK Iron and Steel emissions. This necessitates to (a) establish low-carbon steelmaking plants based on electric arc furnace, (b) develop technologies to make high quality steel from recycled scrap, i.e., examine and mitigate the causes of scrap contamination and develop the opportunities to control the chemical composition of liquid steel made via electric arc furnace, and (c) develop innovative business models to allow UK downstream steel supply-chains to prosper.”

Declared interests

Dr Julian Steer: in receipt of funding from British Steel to measure, and optimise, the performance and selection of their injection coals.

Prof Vlad Mykhnenko: No CoI to declare. One might mention that I co-authored the first feasibility study of green steel industry transition for the post-war Ukraine: Devlin, A, Mykhnenko, V., Zagoruichyk, A., Salmon, N. & Soldak, M. (2024) Techno-economic optimisation of steel supply chains in the clean energy transition: a case study of post-war Ukraine. Journal of Cleaner Production, 466(August), https://doi.org/10.1016/j.jclepro.2024.142675

Prof Roger Kemp: my only prior involvement with the Scunthorpe plant was in 1970 when, as a young engineer working in Bruce Peebles control systems division, I spent a highly stressful weekend commissioning the drive systems for the bar straightening machine on the medium section mill.

Prof David Dye: I have no investments in single stocks or directorships etc; my funding and industry collaborations are related to aerospace companies or is from government. I currently have a collaboration with Liberty Steel but I have no links to the Scunthorpe site.

For all other experts, no reply to our request for DOIs was received.