Moving toward a world of greener steel making

CLIMATE CHANGE

- GERNOT WAGNER ROLAND KUPERS

Burning coal to generate power is so uneconomical that the Trump administration has resorted to issuing stay-open orders to prop up the dying industry.

However, there is one area where coal is still king: in the production of primary iron to make steel.

This matters, because iron and steel production account for over 10% of annual global greenhouse-gas emissions. Most of these emissions come from blast furnaces, where coal is used to strip oxygen from iron ore, producing not only iron but carbon dioxide (the main byproduct).

Fortunately, there are better ways to do this. One is simply to avoid making new iron in the first place. Steel is 100% recyclable, and over one-fifth of the global supply by now is derived from recycled scrap. Recycling requires only electricity, so one can envision a perfect circular economy in which wind turbines produce electricity to produce steel from recycled wind turbines. This is already largely economical in places where scrap steel is readily available, such as the United States and Europe, but less so for fast-growing Asian economies.

Another option is to use natural gas. Only around 7% of steel globally is produced this way, because it does entail some additional costs and complications. Nonetheless, this option paves the way to one of the primary methods of cutting steel emissions to near-zero: replacing gas with green hydrogen.