Power plants are crucial for a modern infrastructure that benefits the society. They supply urgently needed energy for cities, industry and transport. In 1897, Siemens builds South Africa's first power plant, laying the foundation for the country's electrification.
The golden age in South AfricaWhen the world’s largest known gold deposits were discovered in the Witwatersrand district of the former South African Republic (which is now part of South Africa) in 1886, a veritable gold rush ensued. But while coal could generally be mined by hand, gold could only be extracted by machine due to the hardness of the rock – and large amounts of electricity were needed to power the machines. At about the same time, energy demand was growing in Johannesburg and Pretoria. Ultimately, local power producers were no longer able to completely meet the demand. The solution: a three-phase power plant that could supply electric power to the mines as well as to the city of Johannesburg, some 40 kilometers away.
South Africa’s first publicly owned power plant – Siemens brings electricity to cities and mines
Having already been commissioned in 1894 to electrify the mines on the Witwatersrand as well as the up-and-coming city of Johannesburg, Siemens & Halske was awarded a contract to plan and construct a coal-fired power plant in the immediate vicinity of the coal mines in Brakpan. Electricity generated at the plant was transmitted to various consumers in the gold mines via high-voltage power lines. The Rand Central Electric Works (RCEW) near Johannesburg was thus not only the first publicly owned power plant in South Africa but also the first to transmit power at a voltage of 10,000 volts.
Construction work began at the end of 1895 under a contract from Rand Central Electric Works Ltd., a London-based company that had been founded specifically for the project. The plant’s technical equipment was based on the power plants that Siemens & Halske had built to date in Berlin. In addition to the power plant itself, the company built apartment houses, boarding houses and other accommodations for workers and management. This infrastructure was urgently needed, because enough skilled workers had to be recruited from Europe and kept on the job to build and operate the plant.
A power plant built in record time – Commissioning after only two years of construction
After just two years of construction, the biggest three-phase power plant Siemens & Halske had ever built went on line at the end of 1897 — at first with only three of its four three-phase generators, with one being kept in reserve. Each of the Siemens generators produced 975 kilowatts of power with a voltage of 700 volts – thus ranking among the largest generators of the day. To reduce transmission losses, transformers were used to step up the voltage of the generators’ 700-volt power to 10,000 volts. The voltage was then stepped down to 120 volts or 500 volts at the consumer end.
The region’s demand for electricity rose steadily up to the end of the 19th century. In Johannesburg, for example, gas lighting was increasingly giving way to incandescent electric lamps. Furthermore, additional gold mines were being acquired as customers. However, there were also setbacks. In 1899, the Second Boer War broke out between the Boer republics and the British Empire, not only impairing mining operations but also making the power plant itself a target for destruction.
Early in 1901, the rebels blew up the generators — with only one remaining largely undamaged. By the end of the year, the equipment had been rebuilt and power production ramped up again. In 1903, with all four generators running, the plant reached full capacity, supplying half of the electric power for Johannesburg, among other customers.
Dr. Franz Hebestreit