Advances In Decarbonizing Steel & Cement Manufacturing

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Every ton of steel produced using conventional methods creates 1.85 tons of carbon dioxide. The steel industry is responsible for nearly 8% of all global carbon emissions, according to McKinsey. Every ton of cement produced using conventional methods creates 1,800 pounds of carbon dioxide. The cement industry is also responsible for about 8% of global emissions, according to the BBC.

Compare those numbers to aviation, which accounts for about 2.5% of global carbon emissions and shipping at about 3% and it’s easy to see why decarbonizing steel and cement production is a priority if we hope to avoid the worst effects of an overheating planet.

Electra Low Temperature Steel

Electra is a Colorado company that says it has found a way to make iron at 60º C — barely hot enough for a nice cup of tea — using intermittent renewable energy and low grade iron ore. The process of converting iron ore into iron is responsible for the vast majority — 90% — of the carbon emissions associated with making steel.

Speaking with Bloomberg Green last week, Electra co-founder Sandeep Nijhawan said he brought four business ideas, each addressing rising global temperatures, to a meeting in March of 2020 with an investor at Breakthrough Energy Ventures, the climate solutions investment vehicle founded by Bill Gates. There were 7 slides in his pitch deck.

The first one was an idea about how to make iron without coal, intense heat, or emissions, powered only by renewable electricity. “Let me stop you right there,” BEV’s Dave Danielson told him. “If you could do this thing, then that’s what I would do. I don’t want to hear the next three ideas.”

Most iron is made by heating iron ore to 1400º C in a coal-fired furnace. The carbon in the coal combines with the oxygen in iron ore to separate out impurities and unwanted oxygen atoms, releasing huge amounts of carbon dioxide in the process. Later, the iron goes through a series of steps to be turned into steel, but the iron-creation step accounts for 90% of the greenhouse gas generated by the entire process. Producing iron at lukewarm temperatures and without coal would skip the most emissions-heavy step without relying on expensive technologies.

That’s why the idea caught Danielson’s attention. Affordable green steel is a big deal and could disrupt an industry that generates more than $870 billion in revenues each year. BEV invested $2.5 million to get Electra off the ground. To date, it has raised a total of $80 million to pursue its innovative process.

Other companies like Boston Metal are working to decarbonize steelmaking, but their process also involves very high temperatures and lots of energy. Once the process starts, it has to run 24 hours a day, 365 days a year. If it stops, the molten metal solidifies and it can take months to get the process started again.

Because the Electra process works at such a low temperature, it can stop and start at will. That allows it to use renewable energy when it is abundant — and cheap — and stop the process when needed until the next supply of renewable energy comes available.

Other startups are using hydrogen in place of coal but, Nijhawan says, since hydrogen made from renewable electricity is still more expensive than coal, companies are forced to use high grade iron ore, which is a scarce — and expensive — commodity.  “The world is running out of high grade ores that are available for steelmaking,” he says, but low grade ore is abundant. In fact, there are billions of tons of it available.

A full size commercial Electra plant would be much smaller than a conventional steel mill, which is often so large that entire towns spring up around it. Electra will look to build plants that make only 300,000 tons of steel each year, a size that would allow the startup to place itself near existing electric arc furnaces. These furnaces take scrap steel and recycle it, and can also use the iron Electra produces and tweak the process to add more virgin iron than scrap steel.

Electra plants could be located close to iron ore mines, which are typically located far away from urban centers and near land where renewable power can be built without causing a lot of NIMBY related siting issues. The facilities could then process ore into iron onsite while getting rid of all impurities, drastically reducing the volume of material that needs to be transported to a steel plant and further lowering costs.

Electra is now exiting stealth mode and has declined to publicly divulge its exact process. However, it has shared enough details for independent experts to confirm that what the company claims to do is technologically feasible. It expects to begin producing low carbon steel by 2026, Bloomberg Green says.

Low Carbon Cement

Chement
Image courtesy of Chement

Making cement by traditional means also involves high temperatures similar to those used to make iron, often obtained by burning coal. Chement, a startup based in Illinois, says it has invented a way of making cement at room temperature. While the chemistry is such that, even without burning coal, the process produces carbon dioxide, it does so as a pure gas. That way the costs of capture are only a small fraction compared to trapping those emissions from existing cement kilns.

“Day in and day out, we take materials and transform those materials,” says Venkat Viswanathan, an associate professor at Carnegie Mellon University and co-founder of Chement. “Usually that transformation is done at high temperature with heat generated by fossil fuels. But now we can do that with electricity at low temperature.” The company envisions that most if not all the electricity it needs will come from renewable sources.

“Our technology gets rid of the highly-polluting coal fired kilns, using renewable electricity and the same raw materials to perform the chemical reaction with less energy and less CO2 emitted. Chement technology also enables carbon capture that is cheaper and easier than carbon capture in conventional cement production,” the company says.

Ordinarily, when the words “carbon capture” enter the conversation, we quickly stop reading. Most of the time it’s a scam organized by fossil fuel companies that goes like this — let us burn our oil and gas and coal now and we promise (pinky swear) we will figure out a way to capture the carbon we create later somewhere far down the road. We generally say no thank you to such blandishments.

That’s because most of it involves separating carbon dioxide from flue gases, which are composed of all sorts of nasty stuff. Removing the carbon dioxide is difficult and expensive. But if the Chement process results in only pure carbon dioxide, that is a far easier task and much cheaper. If what the company says is true, we are willing to give the idea a respectful listen.

“What’s super interesting about low temperature production is that it’s not just making the process green, it’s requiring less energy,” says Patricia Wexler, a consultant who helps startups scale up their ideas. These technologies are now “less of a scientific challenge, and more of an implementation challenge. If the momentum we have currently stays in place, which I believe it will because of geopolitical and institutional forces, then in five years we’ll start to see major commitments to redo the way we manufacture things,” Wexler tells Bloomberg Green.


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Steve Hanley

Steve writes about the interface between technology and sustainability from his home in Florida or anywhere else The Force may lead him. He is proud to be "woke" and doesn't really give a damn why the glass broke. He believes passionately in what Socrates said 3000 years ago: "The secret to change is to focus all of your energy not on fighting the old but on building the new." You can follow him on Substack and LinkedIn but not on Fakebook or any social media platforms controlled by narcissistic yahoos.

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