Guest essay by Eric Worrall
Steel makers are eager to keep us informed of their efforts to find less carbon intensive ways to produce steel, though they worry production costs will have to rise.
Cleaning up steel is key to tackling climate change
Technology to make grey metal green will not be rolled out commercially until 2030s
Michael Pooler in London 6 HOURS AGO
Globally, steel is responsible for 7 per cent to 9 per cent of all direct emissions from fossil fuels, with each tonne produced resulting in an average 1.83 tonnes of CO2, according to the World Steel Association.
And as the world’s population grows, demand is only predicted to increase.
“In principle there are technology routes to lower emissions from steelmaking,” said David Clarke, head of strategy and chief technology officer at ArcelorMittal, the world’s largest producer by tonnage. The catch, he added, was that “society would have to accept higher costs of steel production”.
A well-established alternative to blast furnaces are electric arc furnaces (EAFs) that melt down scrap, instead of using raw materials. EAFs are smaller, less expensive and, because they do not consume coke, pump out less CO2 than blast furnaces. They already account for about one-quarter of global steel output.
However, renewable energy sources alone cannot meet their enormous electricity demands — enough to power a town of 100,000 people. Another limitation is the supply of scrap, while the grades produced in EAFs are often not the right quality for certain applications, like automotive.
Swedish steel group SSAB is building a €150m pilot facility, scheduled for 2020, that would make the Nordic country the first to manufacture the metal without fossil fuels.
Hydrogen produced by electrolysis from Sweden’s abundant renewable energy resources will be used to reduce ore into a product called sponge iron, which can be converted into steel through arc furnaces.
But clean hydrogen production is expensive and would require a huge expansion of renewable energy generation capacity. South Korea’s Posco and Voestalpine of Austria are pursuing similar projects, although the latter said it could take two decades to become reality.
Until then, steelmakers are taking intermediary steps. Tata’s system removes several stages of pre-processing raw materials and, if combined with the capture and storage of waste gases, the company said it could lower CO2 emissions by 80 per cent.
Renewables rapidly fall down when you consider industrial use. If you focus on domestic use, if you squint hard enough you can produce impressive seeming numbers – “this new solar facility produces enough power for 10,000 homes!”. But when you consider that greening one large factory in Holland (or steel mill in this case) would require the same amount of electricity as 100,000 people consume, and that electricity would have to be reliable, so we are also talking about backup storage, there are a lot of factories in the world.