Is Green Steel In Our Future?
Steel is essential for construction and used as a raw material in many industrial processes with more than two billion tons produced each year. Globally the industry employes six million people and has annual revenues of $2.5 trillion. The carbon emissions created are uneven globally with the greatest amount being issued in countries with low standards. Overall steelmaking accounts for 7 to 11 percent of global greenhouse type emissions.
Modern steelmaking involves several production stages. Iron ore is crushed and turned into a rough solid or pellets. In another area coal is heated to drive off impurities and turned into coke which is pure carbon. The ore and coke are mixed with limestone and fed into large blast furnace where very hot air is blown in from the bottom. Under these high temperatures the coke burns and the mixture produces liquid iron or what is known as “pig iron”. The liquid iron then goes into an oxygen furnace where it is blasted with pure oxygen which forces off the carbon and leaves crude steel as a product.
Where do the emissions come from? The chemical reaction in the blast furnace creates carbon dioxide as the carbon in the coke binds with the oxygen. Also, the fuels burned to heat the blast furnace and the coke plant produce carbon dioxide as a by-product. Globally about 70% of the world’s steel is produced this way which results in about two tons of carbon dioxide for every ton of steel produced. The remaining 30% -- including much of the steel in the U.S. – is made through electric arc furnaces, which use electric arcs to melt recycled scrap steel and this process has far lower carbon dioxide emissions. It is estimated that by 2050 up to 45% of steel can be made this way with the right supply of recycling materials. This will still leave the majority of steelmaking, globally, being produced by primary iron ore-based steel, which creates the most emissions.
A Green Alternative
Every day we hear about “green” products and concepts. Everything from lights, batteries, cars, is touted as a new way to save energy and reduce greenhouse emissions. Well how about an industry that many have criticized as “dirty’ – steelmaking? Can steelmaking be made green?
As you might imagine this is a concept best applied by start-ups. It would be very costly for legacy steelmakers to make the process changes for green steel. Nucor has invested in a company, Electra based in Colorado, which makes iron plates that can be used for steelmaking without consuming fuels such as coal or natural gas. Conventional steelmaking needs 3000 degrees to reduce iron ore. Similar to putting salt in water the Electra process only needs 140 degrees to dissolve iron ore in an acid solution and then electricity is used to separate pure iron from impurities. Another electric current turns the iron into plates about the size of a door frame. The plates are fed into electric arc furnaces and melted for steelmaking by companies like Nucor.
Low temperature requirements mean Electra only needs minimal electricity at any given time. The company can use solar and wind power that would not be effective with conventional steelmaking.
Challenges
Electra and other startups face the problem of scaling up their process to be a significant player in an industry that produces 2 billion tons of steel a year worldwide. Electra hopes to produce 1 million tons in the U.S. by 2030. Large steelmakers will have to see if processes that rely on chemistry and alternative electricity sources can work effectively on a large scale. At that point they will have more confidence to invest billions instead of the hundreds of millions already invested. If a green product is realistic then conventional steelmaking might be labeled ‘dirty’ (as in coal mining) and everyone will want to jump onboard.
