Steelmaking Coal

It might sound odd, but coal is essential to renewable energy! In fact, the more renewable energy we produce, the more coal we will need.

That’s because coal is a key ingredient in steel and things like solar panels and wind turbines are partly made of steel. For example, about 100 tonnes of coal are needed to produce the 185 tonnes of steel used to build a typical wind turbine. 71-79% of a wind turbine's mass is steel.

There are two main types of coal: thermal coal, which is used to generate electricity, including over half of Nova Scotia’s power; and metallurgical coal, which is used to make steel. (Metallurgical coal is also called steelmaking coal or coking coal).

Steel is mainly iron and carbon, and the carbon is derived from steelmaking coal, which typically contains more carbon, less ash and less moisture than thermal coal.

This is how steel is made: steelmaking coal is heated to over 1000 degrees Celsius in the absence of oxygen. Without oxygen, the coal does not burn; instead it begins to melt.

The coal is then quickly cooled in water or air to produce a hard, porous brick of carbon known as coke. The coke is fed into a blast furnace with iron ore and a handful of other ingredients to make molten iron, which is then mixed (alloyed) with other metals to make many types of steel.

About 770 kilograms of steelmaking coal makes 600 kilograms of coke, which in turn produces one tonne of steel using a basic oxygen furnace.

This is the process that produces about 74% of the world’s steel for use in things like infrastructure, computers, appliances, cars, airplanes, rapid transit and all forms of renewable energy. It would be difficult to count the huge number of things in your daily life that steel makes possible.

Each new megawatt of wind power requires 100-160 tonnes of steel because almost every component of a wind turbine is made of it. Steel provides the strength for taller, more efficient wind turbines.

Each new megawatt of solar power requires about 35 tonnes of steel for things like solar panel casings, their bases and various components.

About half the coal mined in Canada is of the steelmaking variety.

While renewables and natural gas are slowly replacing thermal coal in jurisdictions like Nova Scotia, there is currently no commercially viable replacement to steelmaking coal in the manufacturing of steel, so its demand remains high.

Many Nova Scotia coal mines, including Donkin, have produced steelmaking coal. Nova Scotia got into steel production in the 1800s because it has vast coal deposits and the hope was that local iron would provide the second of the two key ingredients.

Learn about Henry Melville Whitney, one of the many larger-than-life figures who played key roles in Nova Scotia’s mining and industrial history, and the Sydney steel plant at