Ironmaking is highly energy-intensive, with about 75 percent of the total demand claimed by blast furnaces. Today’s best practices have a combined demand of just 17–20 gigajoules per ton of finished product; less efficient operations require 25–30 GJ/t.[76] Obviously, the energy cost of secondary steel made in EAFs is much lower than the cost of integrated production: today’s best performance is just above 2 GJ/t. To this must be added the energy costs of rolling the metal (mostly 1.5–2 GJ/t), and hence the representative global rates for the overall energy cost may be about 25 GJ/t for
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