Escom (founded in 1923) was to finance and own the Klip Power Station and the VFP was to operate it as part of its own network. The first generator was started up in March 1936 and the last was put into service in July 1940. With a total of 424 MW of installed plant, the Klip Power Station was the largest steam power station in the Southern Hemisphere, consuming up to 4,5 ton of coal per minute. It was also the first station in Escom to have cooling towers which were more efficient and required much less make-up water than the spray ponds or surface cooling ponds used at other power stations as they evaporated only one per cent of the total water flow. The station was in operation for fifty years, being closed down in March 1986.
Despite the erection of the new Klip Power Station, another extension had to be built onto Vereeniging Power Station in the late 1930’s. In 1936, the station was connected to the Witwatersrand system by means of 80,000 volt lines, those being lines of the highest voltage in the southern hemisphere at that time. By 1938, Escom with the VFP decided to build Vereeniging’s third power station (Vaal Power Station) next to the Vereeniging Power Station, on the opposite bank of the Vaal River in the Orange Free State. World War II caused the commissioning of the Vaal Power Station to be delayed and it finally came on stream in 1945. It was the first station in Escom to have cooling towers which were more efficient and required much less make-up water than the spray ponds or surface cooling ponds used at other power stations as they evaporated only one per cent of the total water flow. The station was closed down in March 1986.
In 1948, Escom bought out the VFP and acquired Brakpan, Simmerpan, Rosherville, and Vereeniging Power Stations and on 1 January 1949, all the VFP employees become employees of Escom. It was during this period that Escom’s founding Chairman, Dr H J van der Bijl who was responsible for the founding of Vanderbijlpark and the giant Iscor (now Mittal) works, died in December 1948. During the 1950’s, the demand for power from the industrial growth in the Vaal Triangle (Vereeniging, Vanderbijlpark and Sasolburg) soared. Escom added boilers and generators to six stations including Vereeniging Power Station. The post war development had made Vereeniging the major centre for steel and engineering industries and earned it the name, "Power House" of the Transvaal.
In 1954, Taaibos Power Station was built near Sasolburg in the Northern Orange Free State, approximately 32 kilometers south of Vereeniging, and in 1959, Escom erected the region’s fifth power station (Highveld Power Station) built on the coal-fields surrounding Vereeniging. Both Taaibos and Highveld power stations each had a capacity of 480MV supplied by 8 turbo generators of 60MW. They were, at the time, the largest and most up-to-date power stations in the Escom system and, because of the limited availability of coal, were intended to be the last of the power stations to be built in the Vereeniging area. These stations completed the greatest concentration of power generating stations in South Africa, the five power stations having a total combined maximum generating capacity of 1813 megawatts.