Decarbonizing steel production

The global fire crisis has brought home the need for a drastic and rapid reduction in emissions of CO2 and other greenhouse gases. We already have the technology needed to replace nearly all carbon-based electricity generation with renewables, and to use electricity to drive nearly all forms of transport.

Among the more intractable problems are those relating to industrial uses, of which the biggest single example is steel. We can make substantial shifts towards a “circular economy” by recycling scrap in electric arc furnaces, but we still need a carbon-free process for producing new steel from iron ore.

The most promising approach (DRI) involves using hydrogen to directly reduce iron ore to iron, which can then be used as feedstock for an electric arc furnace. An experimental plant has just opened up in Germany.

There is a catch, however. The most common approach to producing hydrogen is currently based on burning lignite, which wipes out any reduction in emissions (in the absence of a mythical sequestration technology), as in this LaTrobe Valley boondoggle.

The alternative, based on electrolysis of water requires, as you might expect, cheap electricity. Fortunately, with a marginal cost of zero, solar and wind can potentially fit the bill, at least if the electrolysis process can be adapted to work when power is cheap. Here’s a source claiming that electrolysis is already cheaper.

At this point, it’s clear that the problem isn’t technology or economics. It’s politicians and voters who would rather destroy the planet than admit they were wrong.

43 thoughts on “Decarbonizing steel production

  1. I read about this new use for hydrogen just yesterday. Hydrogen appears to be making a big comeback after a few years being out of fashion. I note the South Australian Liberal government is keen on making SA a major producer of clean hydrogen. That’s great and yet more reason to not worry too much about the dinosaurs in Canberra.

  2. If I catch it at all I rarely watch the trolling Q&A for more than the first few minutes before switching off. This week I watched it for concerning this topic Ross Garnaut captivatingly cited his new book a number of times during their ABC’s Climate and CatastropheQ&A program on Monday. The ABC doesn’t allow Garnaut’s citation in their transcript! A bit dubious a call on vetting product placement one might think. There is some discussion of the book, Superpower: Australia’s Low-Carbon Opportunity, in the transcript:

    I’m chairman of a company, Sunshot Energy, that’s seeking to lead the Australian zero-emissions energy transition. And I’m a shareholder still in the group led by Sanjeev Gupta, bringing low-emission steelmaking to South Australia. And in this role, then, I hope to help lead the Australian effort and at the same time build a strong
    Yeah, well, steel has got two routes to manufacture…

    There’s another route, there’s a zero-emissions route, and that is by using hydrogen. I’ve got half a chapter in the book on how important this can be for Australia. But if we’ve got the iron ore here and we can produce renewable energy, which is the essential ingredient into zero-emissions hydrogen, if we’ve got them both here at lower costs than anywhere else in the world, we would have to be fairly irrational to find ways of avoiding becoming the natural exporter of iron metal.

    It won’t make the slightest sense in the world to take Australian iron ore to Japan or Korea, and to… When… Japan and Korea are committed to being zero-emission economies by the middle of the century. It won’t make any sense at all to take Australian iron ore to Japan or Korea and to take Australian hydrogen to Japan and Korea and to turn that into metal, because hydrogen doesn’t liquefy until it’s nearly at absolute zero. You lose half the energy turning it into a liquid. Then you have got the very high costs of transporting this rather difficult element across the ocean.

    So the economically sensible place to do all that will be here in Australia. A lot of the places will be the places that will lose their coal jobs. The natural places are the Upper Spencer Gulf in South Australia, Collie and Geraldton in Western Australia, Gladstone in Queensland, Newcastle in New South Wales. And these are going to be more jobs and better jobs than are currently in the coal industry…

    This vision for steel, aluminium and in general is exciting.

    Also see:

  3. Quite like the idea of renewables-to-onsite hydrogen. Got a good feel to it if you have a situation wherein by the late afternoon you’ve got mildly compressed hydrogen that could last you all night until mid-morning. But extended hydrogen usage in a production chain is never going to work. Onsite renewables hydrogen production, for usage within (lets say) 72 hours, strikes one as a better fit than renewables to grid. It would be magnificent to re-industrialise with this sort of stand-alone energy all over the place. Good to find as many grid independent ways of producing as we possibly can. Make our whole system more resilient. Particularly during war-time or times of natural disaster.

  4. The purest iron oxide has one oxygen atom to one iron atom and that’s not normally found on this planet. For shits and giggles let’s say the ore averages 1.4 oxygen atoms per iron atom. This means to end up with a kilogram of iron you’ll need to remove 280 grams of oxygen. This will take 18 grams of hydrogen and a temperature of around 850 degrees.

    If solar or other clean electricity is 2 cents per kilowatt-hour and electrolysis is 80% efficient then we are looking at something like a marginal cost of 0.75 cents worth of hydrogen to get 1 kilogram of iron. If the capital costs only doubles that — which is a magical figure compared to today’s capital costs — it will come to 1.5 cents per kilogram. Around $150 per tonne of iron.

    The amount of charcoal required to reduce iron ore to get 1 kilogram of iron is about 105 grams. This means charcoal would have to be 13 cents a kilogram or $130 a tonne or less to compete with cheap hydrogen. It’s like $1,000 a tonne online at the moment.

    Of course, it should be cheaper than this to just use natural gas and then sequester the CO2 directly. This is already being done in a project plant where the CO2 is pumped into an oilfield. Note this only works in a carbon neutral way if you don’t remove oil from the oil field. (They’ve kind of stuffed up on that last point.)

    But if energy is cheap enough to make cheap hydrogen, then the ore could just be heated until it’s close to melting point and it will reduce itself. Maybe you could get an oxygen credit for using this method since we are lower on effective human usable oxygen than we were a couple hundred years ago.

  5. Sounds magnificent doesn’t it. Because Hydrogen is a reducing gas. Very hard to not get excited about this. Particularly the way you outline it all Ronald. For those of you not catching this “reducing” means donating electrons and sometimes forcing off the oxygen molecules while doing so. Oxidising means electron-thieving, often by way of foisting oxygen atoms onto a molecule. So what we are saying is that by its very nature using hydrogen both for the heat, and also to surround the iron oxide during the heating, would seem to be a powerfully efficient way to deal with this iron oxide.

    The only CO2 internment that will ever make sense is soil production. But the rest of this idea seems like a beautiful thing.

    “The most promising approach (DRI) involves using hydrogen to directly reduce iron ore to iron….”

    Once you got the kit and the expertise to pull this thing off you’d never want to go back. Bringing carbon into the process, would thereafter appear to be a dead loss. I never had much of a problem with these headline renewables figures. My problem was bringing them into the grid. But this idea is a whole lot more exciting. There is an inherent excellence about this that goes way beyond renewables for their own sake or renewables for the sake of CO2 mitigation. As always make haste slowly. If we start right away and accumulate the expertise over a long time, then we can keep costs low.

  6. John, that example for low cost hydrogen is just meant to show it may soon be cheaper than converting methane into hydrogen and CO2. It’s still wicked expensive.

  7. A technical point: while it is theoretically possible to decarbonise iron production that way (it’s the basis of the method for making iron based catalysts for ammonia, methanol and synthetic oil production), it is only partly possible – it would be a contradiction in terms – to decarbonise steel production completely as carbon is, by definition, what makes it steel proper (I’m not counting certain special alloys that are only called steel as a title of honour). Given that, and given that it is actually very hard to put in just the right amount of carbon, the technically simple approach is to put in more than enough and purge out the excess by oxidising it. But that just gives you back the methods that were developed historically.

    To be frank, it would make more sense to revert to the pre-industrial approach, and just make iron and steel using charcoal (that’s carbon neutral – think about it). That actually yields a technically superior product (which is why certain special Swedish steels are still made that way), because there are fewer unwanted impurities like sulphates and phosphates that can come in with a coal feedstock.

    Or, if you really do want to do this damned fool thing and you don’t care if you only get iron rather than steel, the cheap and indirect electrolytic way is to ignite thermite made with cheap aluminium refined in a country like Norway using what would otherwise be stranded hydroelectricity. A more direct way is to electrolyse an aqueous solution of an iron salt, e.g. ferrous chloride, surrounding the anode with purified iron oxide to renew the salt by taking up the chlorine, and using a mercury* cathode to take up the iron to be recovered by later distilling. But seriously, there’s a lot of added work to get these “easy” solutions to a non-problem that don’t even deliver the right outcome anyway, i.e. steel.

    * You don’t like mercury? You’d rather have iron whiskers in a salt solution?

  8. The most common steel (mild steel) has ~1kg of carbon per tonne, so worrying about that is pretty silly.


    If you don’t extract the oil, sequestration is an economic disaster.

  10. ” It’s still wicked expensive.” I got a bit lost here. $150/tonne doesn’t sound like much in relation to the overall cost of steel ($500/tonne and up). Can you spell out your point a bit more.

  11. Lazarus at the gate here claims credit for introducing hydrogen DRI to this blog in comments. Dives is of course welcome to take it up, that’s the point.

    BNEF (cited here by Agora: claim that Chinese manufacturers are offering electrolysers at $200 per kw. That’s under half the cost assumed by Goodall. If these work, DRI ironmaking may already be cheaper than coal blast furnaces. Arcelor-Mittal are betting on a pretty sure thing, and the days of coking coal are numbered.


    This isn’t quite correct. The problem is our form of political economy. This extends past politicians and voters making decisions inside this system to the need for making decisions about the system itself. We have to change from this system wherein a small number of large capital owners make decisions which dictate outcomes for the rest of the people and also destroy the environment.

    Things won’t change so long as that small number of large capital owners are permitted to run the entire system as they do currently.

  13. “electrolysis of water requires, as you might expect, cheap electricity.”

    It also requires water, which is in permanent short supply. Of course, you could use sea water, but you’d have to desalinate it first, and that’s expensive.

  14. This will satisfy many here…”hope that we will soon be able to install an electrolyzer in every neighborhood.” Or just a piped hydrogen dream?

    Large nano tube surface area and a stable catalyst;

    “Storing energy in hydrogen 20 times more effective using platinum-nickel catalyst

    …”We have shown that this new catalysts works in a real application.”

    “The stability of a catalyst must be such that it can continue to work in a hydrogen car or house for years to come. The researchers therefore tested the catalyst for 50,000 ‘laps’ in the fuel cell, and saw a negligible decrease in activity.

    “For example, fuel cells are used in hydrogen-powered cars while some hospitals already have emergency generators with hydrogen-powered fuelcells. An electrolyzer can be used, for example, on wind farms at sea or perhaps even next to every single wind turbine. Transporting hydrogen is much cheaper than transporting electricity.

    “Hensen’s dream goes further. He says, “I hope that we will soon be able to install an electrolyzer in every neighborhood. This refrigerator-sized device stores all the energy from the solar panels on the roofs in the neighborhood during the daytime as hydrogen. The underground gas pipelines will transport hydrogen in future, and the domestic central heating boiler will be replaced by a fuel cell, the latter converting the stored hydrogen back into electricity. That’s how we can make the most of the sun.”

    “But for this to happen, the electrolyzer still needs to undergo considerable development.”

  15. “With cheap electricity, about 0.2 c/litre.”

    In terms of the cost of making hydrogen, say enough hydrogen fuel cells to power a car, is that a lot or a little?

  16. @Smith9 If I have it right, we need 17 grams (=ml) of water for one gram of hydrogen. So, 3.4c/kg, which isn’t much. But someone ought to check my calcs on this

  17. The best desalination is water retention landscapes. But also to bring the sea to the land that is below sea level. Like Death Valley. What’s it good for? Should be an inland sea to produce more evaporation. Evaporation is desalination.

  18. Ben McMillan, we shouldn’t worry about the carbon that steel needs – that was my point, that this is part of what makes the perfect the enemy of the good. I’m just pointing out that the goal of 100% decarbonisation is aiming at that, too. Since – paradoxically – the most practical way to get a little carbon is to start with considerably more, a material amount is needed during processing. All up, anyone aiming at perfection will miss the target.

    I should perhaps have reminded people of the damage hydrogen inclusions do to steel’s structural properties; any new processes relying on hydrogen would have to purge those effectively, too.

  19. Like renewable energy, low emissions iron and steel will not start at the finish line and we should not write it off as a failure because it doesn’t – a significant proportion of total production, with a lot of emissions reductions might be readily achievable even whilst getting to 100% remains a problem yet to be solved. There are several serious projects globally for Hydrogen based iron smelting, including Sweden’s Hybrit pilot plant and at least one in the US.

    I think renewable Hydrogen is worth chasing after. Whilst I’m not yet convinced about H2 as transport fuel and think that bulk transporting/exporting will have serious challenges I do think that industrial on-site production and use presents near term opportunities. I would like to see gas generators that can run on mixes with high proportions of Hydrogen fitted with on-site production and storage and dedicated to backup for high levels of wind and solar – that production drawing on solar and wind during periods of abundance and stored for use when wind and solar are constrained. It would not need the high levels of compression/condensation with it’s high energy requirements that transport and transporting appears to need. Days or weeks of storage should be achievable.

    As for relative costs – as long a the biggest subsidy of all, the de-facto one fossil fuels get with their enduring amnesty on externalised climate and health costs persists any comparisons will be very distorted and highly misleading.

  20. More research into direct electrolytic reduction of iron would be good.
    ie Boston Metals Molten Oxide Electrolysis (MOE) is an example.

    I should read this carefully
    Raabe, D., Tasan, C.C. & Olivetti, E.A. Strategies for improving the sustainability of structural metals. Nature 575, 64–74 (2019) doi:10.1038/s41586-019-1702-5

    This article suggests that electrolytic reduction of Aluminium at least can be used to provide short term grid stability
    Holmes à Court, Simon (31 October 2019) Australia’s aluminium sector is on life support. It can and should be saved The Guardian

  21. Actually electricity is pretty expensive to transport, so there are good reasons to use hydrogen pipelines instead, despite the energy costs of compressing it (some of which is recoverable). That means storing hydrogen offsite as well (e.g. in salt caverns), which is probably easier than trying to find a place to store it next to your smelter.

    If you look at a curve of compression energy versus pressure, transporting it at 100 bar isn’t much harder than storing it at 50 bar (maybe 1kWh/kg more).

  22. With regard to my remark that electrolysed hydrogen was still wicked expensive, the figure in the linked to article is 5 pence per kilowatt-hour of energy from methane that is steam reformed to produce hydrogen and CO2. That is 14 pounds per gigajoule or $26 Australian.

    One gigajoule of hydrogen is 7.1 kg and can reduce about 57 kg of oxygen. But hard coke is about $300 a tonne so $26 will buy about 87 kg and this will reduce about 319 kg of oxygen. So $15.50 of coke would be required to do the same job as one gigajoule of hydrogen and would result in 57 kg of CO2 emissions. So it’s still expensive compared to coke given the current absence of appropriate carbon pricing.

    Note I’ve only referred to what is needed for reduction and not for thermal energy.

  23. John, you wrote:

    “If you don’t extract the oil, sequestration is an economic disaster.”

    Well, yeah, but if I’m going to inject CO2 underground then a oil field is likely to be the cheapest option at the moment. This is because it’s already being done and the hardware is already in place.

    If we could be arsed to care about our children on a rational level rather than just an emotional level, we would, right now, take an economically marginal oil field that uses CO2 injection and plug up most of the holes that have been drilled in it and then continue to inject CO2 into it. I don’t know how much CO2 these formations could hold, but it seems to be a lot.

    If we are building new iron ore reduction facilities, since we’re already happy to ship iron ore long distances,they can be built at the oil field.

    If biomethane or charcoal is used to reduce ore it still makes sense to capture and sequester the CO2 emissions.

    Of course, if there are cheaper/better ways to sequester CO2 than injecting it in an oil formation then these should be used instead.

  24. Most of Australia’s oil fields are under the sea. Those that aren’t under the sea are in the middle of nowhere like the Cooper / Eromanga basin around the shared border of Qld. and S.A. Good luck extracting, liquefying, transporting and injecting CO2 into those basins. The money costs and energy costs would be prohibitive. There are far smarter ways, economically and energetically, to reduce CO2 emissions. The smartest way by far is to stop burning coal, then oil and then gas. All solutions which propose CO2 sequestration are a misdirection designed to continue to foster the fallacy that we can safely burn fossil fuels.

  25. Sorry, earlier I wrote that it would take $15.50 worth of coke to do the job of a gigajoule of hydrogen. That’s not right. It’s roughly $6.50. (Just let me check that on my fingers… divide $6.50 by .3 to get 21.7 kg of coke… Each kg of coke reduces 2.67 kg of oxygen so 21.7 times by 2.67 gives 58 kg of O2 removed from iron ore. Yeah, I think that’s right, although I don’t have nearly enough fingers to be sure…)

  26. Yes, Ikonoclast, it’s certainly true that anyone who thinks injecting CO2 underground allows fossil fuels to be safely burned hasn’t thought things through.

  27. Injecting CO2 into oil fields appears to cost around $10 per tonne. CO2 can come from things such as ammonia production but a lot of it comes from natural deposits of CO2 that were trapped underground where it couldn’t cause anyone any harm. Sometimes they just pump natural gas down there instead as it’s cheaper in some locations.

  28. “Injecting CO2 into oil fields appears to cost around $10 per tonne.” Sure but what could be more ridiculous and idiotic than that?” Both the oil and the CO2 will be on the way up in short order. A senseless waste of money, when we have water retention landscapes and soil to build.

    This is an iron law. Any carbon internment not involving soil building is moronic. Its not ever going to change.

  29. DRI processes often use lots of hydrogen already (as a substantial fraction of the reducing gas) so using straight hydrogen is not as radical a change as you might think.

  30. Thanks for the link, Rodney. I do disagree with their suggestion in the introduction that population growth will drive increased metals production. High levels of recycling mean we may have passed peak iron and aluminium ore extraction. The situation with copper is less clear thanks to high demand from wind turbines and electric cars.

  31. Graeme Bird, the oil and gas in the Bass Straits deposits were down there for about 100 million years before we started poking holes in the rocks. If injected CO2 stays there for one tenth that time that’s okay.

  32. No its idiocy and its always going to be idiocy. We don’t have the resources just to destroy wealth with that intellectually handicapped behaviour. I mean this is drooling idiocy stuff.

  33. So, Graeme, just the other day this post apocalyptic survivor at Ellis Air Force base asked me to raise a crashed B-29 Bomber from the bottom of Lake Mead.

    And I was like… “OK Boomer.”

  34. All the energy it takes to inject the CO2 in such a difficult place will create as much CO2 if fossil fuels are used in any part of the compression, transportation, injection process. The idea is non-starter. Nothing wrong with having ideas but the next step is to check them against the hard science.

  35. Exactly. Its a total non-starter. When was the last time you flew over Australia and noticed how dry, and reddy brown it is? And how huge this continent is? If you were to foot-survey the same areas in 100 years time and its all black soil and green covering thats more carbon interred than the hydro-carbon industry has ever produced. Or potentially so. To spend money on energy destroying bullshit when we have a continents worth of land to re-hydrate. This is an automatic F-score for public policy sophistication.

    The real problems of floods, droughts and fires can all be dealt with using water retention landscapes and soil development. Even the non-problem of CO2 levels can be dealt with this way and with powerful efficiency. Soak water into the land and the carbon will follow. Since the water can support a huge amount of subsurface life.

    Time for our leftist academics to get together with our regrarian landscape experts (we are the leading country in this space) and really kick ass. Why don’t some of our academics take some time in the country to talk to people like Colin Seis, Bruce Maynard, Charles Massy and Darren Doherty? A coalition of this nature, if the focus was on the carbon implications of water retention landscapes, would sweep all opposition before it. The conservatives would just ride behind, hanging onto the coat-tails of such a lobby, like small children, not wanting to be left behind. Plus it would be good karma for any academic to be associated with an international superstar like Colin Seis. Good career move in my view. Saving the world could be a good career move surely. To bring the science of land regeneration front and centre into the study of economics. I wonder who around these parts might be well-positioned to entertain such a project?

  36. Hard science? Nah. I’d rather just look at the costs and energy requirements of the pumping of CO2 into the ground that is occurring now in a number of locations around the world. That way I don’t have to wait for peer review.

    Just because some Coalition politician lies and says we can burn coal and inject the CO2 emissions underground, it doesn’t turn his lie into the truth if it turns out it is cheaper to inject CO2 emissions from DRI underground than to use hydrogen.

    We don’t need a bodyguard of lies to protect us from lies. The truth will do.

    You can fight lies with lies if you want, but I don’t think it’s as productive as using the truth.

  37. If you cannot see the ludicrous moronic nature of what you are advocating the idea is just to give public policy away. Its not for you Ronald. Even with the scientific acumen that you have at your fingertips. This sort of thing isn’t for everyone.

  38. Ronald:
    I think you’ve assumed it takes one atom of hydrogen to remove one atom of oxygen (i.e., divided 280g O by 16 to get 18g H), but the ratio is 2 to 1 (H20).

    Also, you’ve converted 1.5c per kg to $150 per tonne, but it should be $15 per tonne (x1000).

    I think that, given a more normal H2 price of $3/kg (your price is $0.83/kg), you would end up spending $100 to get a tonne of iron as DRI.

    So overall this looks not particularly unfeasibly expensive, but obviously more expensive than metallurgical coal. Wouldn’t be surprised if if made a silly arithmetic error somewhere though.

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