Coal’s grip on the global electricity sector is loosening as more utilities and businesses invest in renewable energy. But one big consumer of coal – the steel industry – has a harder time shedding its habit.
Steel companies annually manufacture nearly 2 billion tonnes of high-strength materials for bridges, buildings, railways and roads. Kilns that smelt iron ore to make steel consume large amounts of coal. As a result, the industry represents approximately 8 percent annual emissions of carbon dioxide, as well as a toxic soup of air pollutants.
Steelmakers around the world are facing increasing pressure from government regulators and consumers to decarbonize their operations. This is essential to limit global warming to 1.5 degrees Celsius and avoid most of the worst effects of climate change, experts say. In recent months, the world’s three largest producers – ArcelorMittal in Europe, Baowu Steel in China and Nippon Steel in Japan – have pledged to achieve net zero emissions by 2050, echoing targets set in their home countries.
But to reduce carbon emissions from steel, the industry will need to transform the way the material is traditionally made.
Outside of Boston, in the industrial suburb of Woburn, a company is working to replace coal with electrons. Boston Metal, a company spun off from the Massachusetts Institute of Technology, or MIT, uses electrical currents to heat iron ore into a brilliant orange-white liquid, which turns into metal and cools down into blocks of gray steel. The process does not create greenhouse gas emissions and, when powered by renewable electricity, it can be completely emission free.
Tadeu Carneiro, CEO of the company, said Boston Metal “ushered in a new era in metallurgy.” The 9-year-old startup raised $ 50 million in January from a host of investors, including Breakthrough Energy Ventures, led by Bill Gates, and the venture capital arm of BHP, one of the world’s largest mining companies. The new funding will allow it to build a demonstration plant in Woburn capable of producing 25,000 tonnes of metal per year; so far, the company has only manufactured several tons of steel in total.
Boston Metal’s approach is one of the few breakthrough technologies with the potential to decarbonize steelmaking. Companies are testing systems across Europe that use hydrogen in furnaces instead of coal. In Brazil, some steel mills mix biochar, which is made from agricultural waste. Other companies continue to use coal, but are considering upgrading their facilities with carbon capture devices to offset emissions.
Testing and scaling technologies that eliminate emissions from steelmaking are not the only challenge to decarbonizing the building material. Greener products also have to compete in an industry with relatively low profit margins and an oversupply of cheap Chinese steel.
To level the playing field, public agencies and private companies will need to define policies that encourage the purchase of emission-free steel or that make it more expensive to purchase conventional supplies, said Nate Aden, senior researcher at World Resources. Institute that studies the industrial sector. transformations. (California, for example, limits the total amount of carbon emissions associated with steel and other materials used in state-supported construction projects.)
“We haven’t had enough research and development in this space over the past two decades,” Aden said. “It’s exciting.”
About 70 percent Today’s steel is made as it always has been: in giant, extremely hot ovens. Purified charcoal, or “coke,” is heated and melted with iron oxide and limestone, then injected with oxygen to reduce the carbon content of the mixture and remove impurities.