Energy efficiency in steel is about striking when (and where) the iron is hot
The steel industry has made greats progress in boosting efficiency but major gains now will be harder to find.
Much of the discussion around energy efficiency tends to center on replacing inefficient devices with newer, more efficient components. Look no further than the humble light bulb, which is now on its third iteration (LEDs, before which came compact fluorescents and the now almost archaic incandescent bulb).
This is perfectly logical, but when it comes to industrial settings, the process itself is just as important as the components used in it, often more so.
Take steel, for example. The industry represents 25 percent of global industrial energy use, not to mention 15 percent of all industrial CO2 emissions (this from ABB’s forthcoming Energy Efficiency Trends report). It is, in fact, the largest single industrial consumer of energy, but the vast majority of it is used not in making steel per se but in making the iron precursor.
Energy use in steelmaking could be reduced by 40 percent, or around 250 Mtoe, if the main producing countries were to have the same energy efficiency as that achieved by the world’s best performer through its current mix of processes. However, that might be a tall order. Replacing components like motors with more efficient units will certainly yield results, but any major advance in the efficiency of steelmaking will need to address the iron making process itself.
Electric arc furnaces (EAF) are more efficient than blast furnaces, but the EAF process is used mainly to melt down scrap metal rather than to fabricate from scratch. This recycling process is so effective, in fact, that according to a report from Climatevision, the industry has now reached a point where the supply of scrap is almost fully accounted for.
According to a 2008 World Steel Association report, energy use in the industry was cut in half over the thirty year period from 1975 to 2004 but the trend line is leveling out. Going forward, the industry will need to look deeper into things like process controls and design to take efficiency to the next level.