The Years of Consolidation - "Demand for electricity soars"

To an ESCOM planner in the 1960s and 1970s the idea that South Africa could end up with too much power capacity must have seemed laughable.  Putting aside the post-World War II boom the 1970s saw the biggest growth in electricity consumption in South Africa’s history.  In 1973 demand grew by 12%, and by 13% the following year.  The average annual growth for ESCOM’s 6th decade was almost 9%.  The problem with good times, and for that matter bad times too, is that they seem like they’ll last forever.  
Growing international pressure towards South Africa’s apartheid government seemed only to harden its resolve.  
 In spite of growing isolation there was still strong global demand for South Africa’s gold, minerals, iron ore, steel and coal.  What South Africa lacked was oil and gas.  Thus it was that ESCOM relied so heavily on coal, and particularly low-grade coal (or ‘black-painted’ rock as some power station operators called it).
And so the 1970s saw ever bigger coal-fired power stations popping up in the Mpumalanga veld.  Arnot had begun commercial service in 1971, and it was becoming apparent that its 350 MW sets (massive for the time), would be too small for future stations.  With an annual growth in power demand of 9%, ESCOM would need to double capacity every eight years, which translated to a further 10 000 MW by 1980.  Kriel was the first of the ‘six-packs’ (so-called because of their 6 tall, and very prominent, boiler houses) and featured new ‘once-through’ technology  whereby steam “bypasses the turbine while the boiler is warmed up or when the turbine is shut down.”  
In 1973 ESCOM celebrated its 50th anniversary – a comparatively youthful newcomer to the ranks of public utilites.
From the start there were challenges in getting the most out of Kriel, which was once ESCOM’s biggest power station.  The boilers were susceptible to slagging, and new mill foundations had to be built when the heavy milling machinery created dangerous vibrations.  On completion, in 1979, Kriel consisted of 6 sets of 500 MW each and was one of the largest coal-fired power stations in the southern hemisphere, as well as being of the world’s first to receive its coal from a fully mechanised coal mine.  
Meanwhile, Duvha, like Kriel, was a ‘six-pack’ power station with separate housing for its turbine generators.  Unlike Kriel the boilers were of a conventional design and used natural circulation and not once-through.  Kriel began commercial operation in 1979 and on completion (in 1983) boasted six sets of 500 MW each.  It was distinctive for its boiler house superstructure; constructed from concrete in order to reduce lead time and capital costs amidst a world shortage of steel.  
Duvha Power Station was the third and final ‘six-pack’ and was built near Witbank in Mpumalanga.  It, too, used a ‘once-through’ boiler technology, but instead of six 500 MW sets it consisted of six 600 MW sets.  The boilers proved more reliable than Kriel’s, but there were still challenges, particularly of an environmental nature.  The precipitators on Duvha’s first three units did not reduce emissions to acceptable levels and the pollution problem was only solved in 1984 when the offending units were retrofitted with pulse jet fabric filter plants – a world first.  Another first for Duvha came in the form of a man by the name of Mr Ehud Matya – ESCOM’s first black power station manager: but that’s a story for a later edition. 
In the 1970s ESCOM’s environmental challenges paled into insignificance compared to the crisis that it faced on 5 December 1975.  An interconnected transmission system, while preferable, had its risks, and faults could spread to the entire country.  This is exactly what happened on that particular day, when a relay malfunctioned at the Hydra Substation near De Aar.  Much of the country went without power for 24 hours, and ESCOM had to rethink its transmission system.  In 1976 ESCOM addressed the problem by building two gas turbine stations, one near Cape Town, the other near East London. 
1976 saw the completion of Hendrina power station and Gariep (then Hendrik Verwoerd) hydro-power station, (Arnot had been completed the previous year).    
ESCOM itself was not a capitalist enterprise and in the 1970s many South Africans began to see it as inefficient, especially when the price of electricity started to rise.  The problem was that ESCOM had to finance most of its own growth. At the same time ESCOM feared that if they did not expand the country would run out of power.  In 1977 consumers were paying 166% more for electricity than in 1971.  Unsurprisingly, the move to Megawatt Park in 1977 was not greeted favourably by the public who saw it as an example of ESCOM’s wasteful expenditure.  The upshot of all this was that in 1977 the Minister of Economic Affairs asked the Board of Trade and Industries to investigate the supply of electricity in South Africa.
ESCOM co-operated with the board to seek out the best solution for the utility and for the South African economy.  In the end ESCOM did away with the Central General Undertaking (CGU) and modernised its accounting system.  Although the Capital Development Fund (CDF), and ESCOM’s insistence on large reserve plant margins, came under attack, they were ultimately defended by the government, who shouldered some of the blame for the sharp price increases.  ESCOM defended its spending on expansion by arguing that without it South Africa would have faced not only an oil shortage crisis, but an electricity shortage crisis, too.  In 1979 Jan H Smith, ESCOM’s General Manager at the time, lambasted the Board of Trade and Industry for their use of the word ‘profit’.  Then, as now, the term is a potentially misleading one, given that ESCOM’s profits do not enrich private investors but are used to expand South Africa’s electricity system.
In 1980 the Chairman of ESCOM, Reinhardt Straszacker, retired and it was the same Jan H Smith who grasped the baton.  Smith, who raised tortoises as pets, because he admired their tenacity as he was known for being a ‘man in a hurry’.  He was nicknamed ‘Mr Kilowatt-hour’, a reference to his ability to reduce complex planning issues to the effect they would have on the cost of a Kilowatt-hour of electricity. 
Jan H Smith

Unfortunately for ESCOM, although Smith was famous for being a top class planner, he over-estimated South Africa’s future electricity needs.  He wasn’t helped by the fact that there were delays in the building of Koeberg, and the power from Cahora Bassa (then called Cabora Bassa) was so unreliable as to be arguably worse than no supply at all.  With sanctions starting to bite it was feared that ESCOM would be unable to complete Koeberg at all and so certain planning schools of thought discounted nuclear power from the equation.  The upshot was that ESCOM urgently began building more power stations in anticipation of continued high growth in demand.  The early 1980s saw construction begin on Lethabo, Matimba and Kendal power stations.  This would add almost 12 000 MW to the system, and create a problem that seemed almost unthinkable at the time: what to do with masses of excess electricity. Hendrik Verwoerd (re-named Gariep) hydro power station started feeding into ESCOM’s transmission system in 1971. Not only did it prove of value in peak load periods and emergencies,  but it stabilised the 400 kV line linking the Transvaal and the Cape Province. Vanderkloof, a similar hydro power station, was commissioned in 1977 as another feature of the Orange River Project.

 ESCOM decided, in 1972, to build Koeberg nuclear power station approximately 30 km from Cape Town. This development was necessary to cope with the increasing demand for power in the Western Cape. Use was to be made of the uranium enrichment process developed in South Africa.
The 1970s brought further exploitation of the Eastern Transvaal coal-fields. The erection of Matla (3 600 MW) and Duvha (3 600 MW) power stations was undertaken.
The erection of the Drakensberg Pumped Storage Scheme challenged ESCOM in the seventies. Not only was this hydro station designed to supply 1 000 MW of electricity during peak periods, but it was to assist in supplementing the contents of the Vaal Dam (south of Johannesburg) with water transferred from the Tugela River in Natal.
 Acacia (171 MW) and Port Rex (171 MW) gas-turbine power stations were commissioned in 1976.
ESCOM moved to a new Head Office building in 1977. Megawatt Park, in Sandton, is a show-piece that emphasises ESCOM’s leading role in the development of South Africa and its people.
Vanderkloof Power Station​
Gariep (previously known as Hendrik Verwoerd)
Matla Power Station
Duvha Power Station​
Megawatt Park​
Koeberg Nuclear Power Station
Drakensberg Pumped Storage Scheme​