Hydroelectric power aluminium

Most aluminium is derived mainly from an ore called bauxite, which produces approximately 1 tonne of aluminium from 4 tonnes of ore and is a highly energy intensive process. As a result of this, aluminium is widely produced and used in those countries which have the cheapest energy supplies, e.g. hydroelectric power. Aluminium is one of the lighter metals with a density of 2.7 (note that glass lies between 2.25 and 2.5, covering neutral and soda glasses). 

The electrolysis of aluminium oxide is a continuous process in which vast amounts of electricity are used. Approximately 15 kWh of electricity are used to produce 1 kg of aluminium. In order to make the process an economic one, a cheap form of electricity is required. Hydroelectric power (HEP) is usually used for this process. The plant shown in Figure 5.7 uses an HEP scheme to provide some of the electrical energy required for this process. Further details about HEP are given in Chapter 6, p. 94. 

Some electrically-intensive industries may be located in regions inconvenient to the national electrical grids and/or may find it to their strategic advantage to control their own power supplies. The ownership and operation of hydroelectric facilities by American and Canadian aluminium companies is an example. The energy requirements for an industrial park can match the output of one or more smaller nuclear reactors located nearby, while a conveniently located hydroelectric project is rarely feasible. 

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