Green Steel: A More Environmentally Friendly Way to Manufacture

From the early days of the industrial revolution, there was one way to make steel: blast furnaces that pumped toxins into the air while producing the metal that forms the backbone of buildings, bridges, and vehicles.

But in recent years, a different type of industrial revolution has taken place as manufacturers in nearly every economic sector are finding ways to make their processes more environmentally friendly.

In Darlington, South Carolina, Nucor Steel produces “green steel,” made without the toxic emissions from blast furnaces.

Nucor “brought green steel to the U.S.” more than five decades ago, said Jason Friedenberger, the vice president and general manager of the company’s South Carolina operations.

Nucor was the first in the U.S. to use electric arc furnaces, known as EAFs, which take scrap steel from automobiles, washing machines, and other metal objects, and recycle them into new steel, Friedenberger said.

According to Nucor, the green steel manufacturing process yields an average of 0.77 metric tons of CO₂ per metric ton of steel, compared to blast furnaces, which produce around 2.33 metric tons of CO₂ per metric ton of steel.

Companies in the U.S. are no longer building old-school blast furnaces; even the oldest steel manufacturers are working in a more sustainable manner, Friedenberger said.

Green steel has a different manufacturing process than traditional steel, but the resulting product is identical, Friedenberger said.

“It’s all got to meet certain specifications,” he said.

How to source the iron

As laid out in Nucor's case study on the supply chain of green steel, now that Nucor has helped popularize the use of electric arc furnaces in steel production, the next area to shore up on efficiency and total-carbon-reduction is its supply of iron inputs. 

Steel making requires a multitude of inputs during the smelting process to ensure the proper balance of alloys for each product's specifications, with one such input, naturally, being iron. Steel producers source their iron in many forms, with some of the most common being direct reduced iron (DRI) and pig iron.

Pig iron, as defined by Majestic Steel USA, a national distributor and processor of prime carbon flat-rolled steel, is an iron-carbon alloy, and is the most common form of intermediate iron globally, serving as the bridge between raw ore and finished steel and iron products, and is created by smelting iron ore in a blast furnace.

SteelWatch, an international watchdog and civil society organization driving decarbonization, produced a 2025 explainer on the necessity of a "green iron trade" to fuel the decarbonization of the steel industry. The document explained that coal-based ironmaking in blast furnaces accounts for 90 percent of global "virgin iron" produced. Virgin iron is produced directly from iron ore instead of scrap, and is most commonly rendered into pig iron. This pig iron is then used in 70 percent of global steel production.

This method of turning iron ore into pig iron imbues the iron with a large amount of carbon, around 4 percent on average, and does not remove the silicon and other slag impurities, which must be rendered out before becoming steel.

‘Sustainability is an imperative’

Sustainable manufacturing practices have taken hold in the U.S., and in South Carolina in particular, as companies prioritize environment-friendly ways of making their products, said Leslie Skardon, CEO of Sustain SC, which works with businesses and other entities to protect the environment and boost the economy.

“I would say sustainability is an imperative for these companies, especially the companies that are headquartered overseas, in Europe or Canada or Japan,” Skardon said. “Many of them have sustainability requirements that they have to meet, regardless of where they are, if they’re in the EU or not. They have mandates from their headquarters to be carbon-neutral, to get to zero waste, and so they have to figure out how to do that in their facilities in the U.S. and in South Carolina.”

Helping global companies meet their carbon-reduction compliance requirements in the U.S. is becoming easier, however. As reported by Ember, a think tank focused on the transition from fossil fuels to clean energy, June saw the production of solar power in the U.S. overtaking coal electricity generation for the first month ever on record. Solar supplied 12.8 percent of US electricity, a record for its category, while coal dipped to 12.2 percent, the fourth-lowest monthly energy share ever recorded. 

For a non-EU global comparison highlighting energy self-sufficiency in line with the carbon goals of the Paris Climate Agreement, in 2025, the largest global producer of solar energy was China, producing a total of 1,175 TWh of solar power. As outlined by Anna Fleck, a data journalist with Statista, not only is this over three times the amount of solar power produced by the U.S. in 2025, it also amounts to 42 percent of China's total annual electricity produced.

Sustainable manufacturing helps more than the environment, Skardon said.

“There is a growing understanding that sustainability isn’t just good for the planet, it’s also  good for profit,” she said.

When a company can reduce its energy consumption, that also cuts down energy and water costs, and if they can turn the waste products from manufacturing into another product, “you’re creating a brand-new business line,” Skardon said.

Reducing the carbon footprint of iron

Direct reduced iron, as defined by the International Iron Metallics Association, is made from iron ore being directly rendered into iron via a reducing gas containing carbon, typically from natural gas, coal, or hydrogen. The rendering process is significantly more fuel efficient due to not requiring the use of a blast furnace, and DRI is most commonly utilized in conjunction with electric arc furnaces. DRI contains roughly the same amount of iron content as pig iron, and has the added benefit of being able to, immediately upon reduction, be added to an electric arc furnace's steel scrap charge, retaining its heat from the reduction process, further saving on fuel and energy costs.

Blast furnaces have a benefit, from a production and profit-motivated standpoint, of continuously running, which is encouraged all the more due to the significant time it takes to start up a furnace once it's gone cold. In an effort to reduce both costs and emissions, blast furnaces are most often integrated into steel plants, allowing for the refining of iron ore into steel to take place with the least amount of transport costs and fuel use.

The “cheap steel” produced in many other countries not only produces harmful emissions during manufacturing, but the process of importing it is also less environmentally friendly than sustainable steel manufactured and sold in the U.S., Friedenberger said.

And, he added, it costs jobs for American workers.

As outlined by SteelWatch's 2025 explainer, iron- and steelmaking accounts for 11 percent of all global CO2 emissions. With global blast-furnace ironmaking being an input relied on by 70 percent of global steelmakers, it also accounts for 90 percent of steelmaking's carbon emissions.

The green iron breakthrough

An explanation of how things have been done, and which are still being done globally, gives the frame of reference for innovation in production and manufacturing being undertaken by companies like Electra, a green iron company in which Nucor invested in 2022.

Both DRI and pig iron rendering processes require relatively high-grade iron ore inputs, and do not allow their subsidiary waste products to be immediately reused or rendered into secondary products. Electra has taken green iron ore rendering one step further than DRI through a patented low-temperature electrochemical-hydrometallurgical system which refines iron ore into high-purity clean iron while also separating out its co-minerals, like silica and alumina, for further use in production.

Utilizing a proprietary water-based acidic solution, Nucor's green steel supply chain case study describes Electra's system as dissolving iron ore at a temperature "no hotter than a cup of coffee" (sub-140 degrees Fahrenheit), thus suspending the iron in the solution. The co-minerals present in the ore are collected while simultaneously regenerating the acid solution. Finally, electricity is run through the solution of suspended iron particles, electrodepositing the now-purified iron onto metal sheets.

Solving problems of both scale and efficiency, Electra's system is designed as a network of connected cells, with each repeatable, modular unit being built using readily available equipment and materials. Not only cost-effective, Electra's goal is rapid global scalability.

This breakthrough process from Electra lines up with Nucor's vision for a net-zero, science-based greenhouse gas target for 2050, a company goal aligned with the net-zero carbon emission by 2050 goal outlined by the Paris Climate Agreement.

Picture this: an Electra system in a mini-mill which utilizes an electric arc furnace. The initial iron ore sourced from the "waste" of a local or national iron mine. The plant itself is outfitted with solar panels to subsidize its electricity use. The rendered-out silica and alumina can be sold back into the market for profit. Sourcing scrap steel from junk yards and automotive manufacturers, the carbon credits produced from such an operation are at once eco-friendly and profit-motivated. In such an operation, the remaining sources of carbon emissions come from transportation/trucking costs and a reliance on fossil fuel energy from the local power plant.

Even so, considering the rise in the use of electric batteries in commercial trucking operations and an increasingly global turn to solar, a carbon-reduced manufacturing base isn't a lofty hope; it's entirely possible right now.

Sustain SC works with suppliers as well as manufacturers to make sure that they are using environmentally friendly practices in producing the products that the manufacturers use.

Making products here and shipping them to other parts of the country benefits the economy in multiple ways, Skardon said.

It can keep the manufacturing process moving smoothly if the components come from a few miles away rather than a few thousand, especially if there is a supply chain disruption, Skardon said.

“If you are local, you don’t have to worry about tariffs or international conflicts,” she said. “The impact of oil prices is smaller, so from an economic perspective, an uncertainty perspective, there are lots of advantages as well.”