Lethabo Power Station
Construction of the Power Giant of the Vaal Triangle started in 1980. The station was built on 11 000 concrete piles which were sunk 25 metres deep to alleviate the heaving clay problem after some 190 000 bluegum trees were removed during site clearing. The first of its 6 x 618 MW generating sets went into commercial operation in December of 1985. The station became fully operational in December of 1990. It has the capacity to generate 3708 MW, and at full load, Lethabo’s generating sets consume approximately 40 000 tons of coal per day, at the same time producing close to 16 000 tons of ash. The Lethabo power station is currently expected to operate until 2037, although the actual life of the power station depends on its economic viability in the future.
Lethabo holds the distinction of being the only power station in the world capable of burning a low grade coal. The coal, which has a calorific value generally in the range of 15 to 16 MJ/kg, is supplied from the Anglo Coal’s nearby New Vaal Colliery. The unusually low quality of the coal means that it also has a very high ash content of up to 42%. In keeping with national environmental legislation, electrostatic precipitators, the largest of their kind in the world, have been installed at Lethabo. The precipitators remove 99.8% of the fly ash present in the gases that are released through the smokestacks. The cement industry uses the ash as a cement extender, thus reducing the water demand of a concrete mix. Almost 250 000 tons of ash from the Lethabo Power Station was exported to Lesotho for the Katse Dam project.