Energy-intensive industry

Steel, cement, aluminium, ammonia and chlor-alkali, where energy is a large part of cost.

Conversion and use · Industry, buildings and farms · No. 117

• Conversion and use

A tonne of steel took about 50 GJ in the 1960s; today it takes about 21, and chemistry sets a hard floor.

Chart: Illustration: Energy-intensive industry

Where it comes from

Chart: Map of where it comes from

Most metals sit in rock bound to oxygen, and breaking that bond takes a fixed amount of energy. A blast furnace uses carbon to take the oxygen; hydrogen or electricity can do it instead.

Three things to know

1. The best plants now use about 1.5 to 2.5 times the chemical minimum energy to turn ores into metals and chemicals.
2. About half of cement's CO₂ (53%) comes from the limestone itself, so cleaner fuel alone cannot fix it.
3. Compressed air turns only about 10% of its electricity into useful work at the tool.

The journey

1. 1 Ores and fuelsIron ore, bauxite, limestone, gas, salt
2. 2 Energy inCoke, gas or electricity supplies heat
3. 3 ReductionOxygen stripped from ores by carbon or electrons
4. 4 Bulk materialsSteel, aluminium, clinker, ammonia, chlorine
5. 5 End useBuildings, vehicles, fertiliser and chemicals

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