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Klip Power Station

OVE​RVIEW

Klip Power Station was built as a result of the rapid growth in the demand for electricity that followed the increase in the price of gold in 1933. The first generator was started up in March 1936 and the last was taken into service in July 1940. With twelve 33 MW generators and four 7 MW house sets, giving a total of 424 MW of installed plant, Klip had the distinction of then being the largest steam power station in the Southern Hemisphere. As far as is known, it had the greatest output of any power station in the world at that time, and probably the lowest cost of production of any other similar station. The rate of construction and commissioning of plant constituted another world record. It was the first station in ESCOM to have cooling towers. [The name ESCOM was changed to Eskom in 1987]. The station was in operation for almost exactly fifty years, being closed down in March 1986. Total net electricity production amounted to slightly over one hundred thousand GWh (gigawatt-hours) or one hundred thousand million units. The total coal consumption was 84,5 million metric tons. (​​ESCOM Annual Reports 1936:33, 1943:12, 1985:56 note 2) and Tables of Power Station Operating Statistics; Pickles & Trelease 1940:1; Eskom News Sep/Oct 1993:9)

 When completed in 1940, the station capacity was over four times that of Witbank Power Station, previously the largest station owned by ESCOM. However, today it would need more than two-thirds the total capacity Klip had at completion to supply just the auxiliary requirements of a power station such as Majuba or Matimba.

 
  ​Klip Pow​er Station
  

BACKGROUND

With South Africa in the grip of the world-wide depression, at the end of 1932 the Government decided to abandon the gold standard. A sharp rise in the price of gold followed and the country began to experience rapid economic growth. The phenomenal increase in demand for electricity created by the expansion of the gold mining and other industries made it clear that an additional power station would be needed. (ESCOM Annual Report 1943:11)

KLIP200.jpg
Aerial view of Klip power station with the residential houses still under construction

 The total installed capacity of the existing stations feeding into the Rand-Witbank area in 1932 was 360 MW, but it was not practical to extend these stations sufficiently to meet the expected growth in demand. Negotiations were started between ESCOM and the Victoria Falls and Transvaal Power Company (the VFP), with the object of producing power on the most economical basis in the interests of consumers as a whole. An agreement was entered into between the VFP and ESCOM by which a new station would be financed and owned by ​, but be constructed and operated by the VFP on behalf of ​. It was decided in 1933 to build Klip Power Station adjacent to the Klip River (=Stone River) at Redan, about 7 km north-east of Vereeniging. Like Vereeniging Power Station of the VFP, it would be a pithead station. It would be established adjacent to a new colliery shaft from which coal would be mechanically fed right into the bunkers. (Vereeniging Power Station had been the first in South Africa, and possibly in the world, to be sited on a coalfield). Preliminary plans were drawn up by the VFP, but their London engineers and ESCOM​'s consultants, Merz and McLellan, collaborated on the final designs. (ESCOM Annual Reports 1933:5, 1943:11&12; Pickles & Trelease 1940:1; Troost and Norman 1969:178)

For cooling purposes, previous stations had made use of spray ponds (as at Witbank) or surface cooling in ponds with large water surfaces (as at Vereeniging Power Station). Due to the shortage of water in South Africa, ESCOM's Civil Consulting Engineer, Dr FE Kanthack, proposed using cooling towers at Klip in order to conserve water. Spray ponds were cheaper to build than cooling towers, but required from three to five times as much space. Cooling towers were more efficient and required much less make-up water as they evaporated only one per cent of the total flow. ESCOM acquired water rights to 18½ million gallons [84 megalitres] per day from the Vaalbank Dam. By using cooling towers, this would suffice for a station or stations of nearly 1000 MW of installed capacity. The two hyperbolic cooling towers at the Iscor Works at Pretoria were the first of this type to be built in South Africa. The Klip towers were the largest so far designed, and of similar dimensions to those in operation at Hams Hall near Birmingham in England. (Kanthack 1938:2-9)

 
   
 The power station under construction
 
 CONSTRUCTION
 

Excavation work commenced at the site early in June 1934. Only twenty-one months later, the first 33 MW generator and two boilers were placed in commercial operation. Mrs HJ van der Bijl, wife of ​ESCOM's Chairman, started up the first set at the official opening of the station on 10 March 1936. In the next four months three further generators, together with the necessary boilers and other auxiliary plant, were placed in service. The initial intention was to provide four sets, with further additions being made later. In actual fact, construction proceeded in a continuous programme until all twelve main sets had been installed. The last two 33 MW sets were placed in service on 4 January and 15 July 1940 respectively.(ESCCOM Annual Reports 1936:33, 1940:20)

The site of the station, at an altitude of 1468 metres above sea level, consisted of approximately 140 hectares and was formerly open veld. It was situated in the coalfield of the Springfield Colliery, but the station itself was on a bed of dolomite overlaid by a stratum of clay and a layer of weathered rock. The foundation blocks were kept within a maximum depth of two metres to prevent intrusion into the clay. The main station buildings were steel-framed with external walls brick-filled 9 inches [230 mm] thick. The total weight of structural steel in the completed building was approximately 7200 metric tons. The ground area covered by the main buildings (excluding stores, workshops and general offices) was about 24 thousand square metres. The turbine house was 250 metres in length. (Pickles & Trelease 1940:2-4)

 A summary of the principal equipment installed is as follows:

Year Main Generators House Sets Boilers
1936 4   8
1937 2 2 4
1938 2 1 6
1939 2   4
1940 2 1 **
Total 12 4 **24
 
 

** The last two boilers were delayed by the outbreak of World War II (1939-1945), but were in service by 1943. However, as the boilers were interconnected and each could deliver an extra amount of steam, this did not materially affect the station output. An additional boiler of the same capacity was installed in 1958. (ESCOM Annual Reports 1935-1944, 1958:46; Conradie and Messerschmidt 2000:92)

  The boilers were manufactured by Babcock and Wilcox, and were of the cross-drum marine type. They were fitted with chain grate stokers, airheaters, economisers, water tube furnace walls, superheaters, sootblowers and cyclone grit and dust collectors. Each unit was rated at 180 000 lb/h [22,7 kg/s] normal continuous rating. The steam pressure at the superheater outlet was 355 lb/sq.in. [2,55 MPa (abs)] at a temperature of 390/405 °C. Each boiler was provided with a separate steel chimney 8 feet [2,4 m] in diameter. These were originally 240 feet [73 m] high with the upper 100 feet [30 m] constructed of copper bearing alloy. The chimney height was later reduced to 56 m. To save costs, the chimneys were not free-standing but were tied to each other and anchored to the station buildings by means of steel stay-wires. Each bank of eight boilers was provided with a separate and independently operating ash handling system, and an ash disposal ropeway discharging onto an individual dump. The speed of the ropeway was 390 ft/min [2 m/s].

The 12 main turbo-generators were each of 33 MW economic and full load rating. These were the largest units, which at that time could be transported from the coast. There were also four 7 MW house sets. The steam pressure at the turbine stop valves was 350 lb/sq.in. [2,51 MPa (abs)] at a temperature of 390 °C. The main turbines were of the two cylinder double exhaust type manufactured by Metropolitan Vickers and the house sets were of single cylinder design. Two emergency steam driven feed pumps were installed.

Each generator transformer consisted of three single phase units of 13,333 MVA capacity. The voltage on the generator side was 10,5 kV (delta) and on the secondary side 88 kV (star). These transformers were water-cooled. The house sets were connected to the 2,1 kV station boards via 8,75 MVA reactors. Four station transformers of 8,5 MVA each were also provided to supply the 2,1 kV boards from the 88 kV bus-bars.

There were 10 cooling towers. The diameter at the base was 170 ft [52 m] and at the top 92 ft [28 m]. The height from the bottom of the ponds was 220,5 ft [67 m]. The weight of concrete in each tower was 2400 metric tons and the weight of steel reinforcing in each 360 metric tons. The quantity of water circulated in each tower was 1,98 million gallons per hour [2,5 kl/s]. The designed inlet and outlet temperatures of the water were 38 °C and 28 °C with an atmospheric temperature of 21 °C and humidity of 75%. The actual average operating temperatures in 1940 were 30,4 °C and 22 °C respectively. Make-up water was taken from the Vaal Bank Dam and pumped from the Vereeniging pumping station. The average water usage of the station was 5,7 l/kWh sent out.

Capital expenditure during construction amounted to approximately £6,3 million. A breakdown of these costs is given below (excluding Land and Rights £ 129 993)

Buildings (power station) £ 610 988
Boilers and ash plant £ 2 407 133
Turbines and generators £ 1 196 734
Switchgear, transformers and cables £ 558 314
Pipework £ 328 705
Cooling towers, ponds and ducts £ 669 637
Coal plant £ 186 180
Railways, roads, miscellaneous £ 316 936
TOTAL £ 6 274 627
 
  
 
  
(Information and data source for technical details from: Andrews 1937:22-24;
Kanthack 1938:2-9; Pickles and Trelease 1940; ESCOM Annual Report 1940:21;
ESCOM Twenty-five Years 1923-1948:45)
 
 
 
  Aerial view of the power station
 
 OPERATION AND PRODUCTION
 
  
 
 

From 1940 to 1961 the station net production averaged approximately 2 500 GWh per year. For the next 22 years, as the operating function of the station changed from base-loading to peak-loading, production dropped fairly steadily to about 1 300 GWh per annum. However, maximum net power remained consistently close to the full sent-out rating of 394 MW until 1977. During the closing years, 1984-1986, production was much reduced.

 
  
 11 of the 12 generating sets
  
Maximum net annual production was 2 763 GWh, sent out in the year 1952. Maximum net power was 399 MW, produced in the year 1967. Maximum thermal efficiency was 21,8% and was achieved in the year 1941. Statistics for these years, as well as the first and last full years of production, are given in the table below.
 
Year Net Generation GWh Net Max
Power
MW
Load Factor (net basis) % Thermal Efficiency net basis % Coal
Consumed
metric ton
Calorific
Value of
Coal MJ/kg
Cost of
Coal
R/metric ton
1937 1 350 219 85,1 21,4 996 267 22,42 0,33
1941 2 676 375 81,4 21,8 2 010 333 21,98 0,39
1952 2 763 375 82,5 20,3 2 238 718 21,06 1,07
1961 2 480 392 72,2 20,3 1 854 799 23,70 2,36
1967 2 059 399 58,9 20,1 1 695 542 21,12 2,91
1977 1 447 378 43,7 18,2 1 380 840 20.74 Not available
1983 1 335 301 46,9 17,5 1 499 626 18,35 Not available
1985 348 225 17,7 14,9 469 706 20,39 Not available
 
Auxiliary consumption in the station varied from about 6% to 9% of generation, depending on the load factor, with an average of approximately 6,5%. (ESCOM Annual Reports-Tables of Power Station Operating Statistics)
 
 
 33 000 kW a​xial-flow turbine at Klip Power Station
 

 COAL SUPPLIES

Coal was initially supplied from the Springfield Colliery and was raised through two shafts, the East and the West. The East shaft was located immediately adjacent to the station and delivered the coal via a relatively short conveyor belt system. Coal supplied from the West shaft was delivered via a rail connection approximately 2½ km long in 40 ton hopper wagons drawn by steam locomotives and dumped into an open staithe. Both shafts had their own crushing and washing plants, the coal being crushed to minus 3/4 inch [19 mm]. The calorific value of the coal from this colliery was initially over 9 500 Btu/lb [22,10 MJ/kg], but dropped to about 9 000 Btu/lb [20,93 MJ/kg] by 1950. (Pickles and Trelease 1940:3; ESCOM Annual Reports-Tables of Power Station Operating Statistics)

 When the station was planned, it was estimated that the mine could supply the station for 40 years. However, by 1948 it became apparent that the coal was becoming exhausted and coal would have to be brought from further afield. Plans were made "for the construction of a 40-mile [65 km] railway to bring coal to feed the furnaces of the Southern Hemisphere's largest power station". By 1953 the Springfield colliery was closed down. Coal was railed in from Cornelia Colliery and the calorific value then increased again to over 22 MJ/kg. (ESCOM Twenty-five Years 1923-1948:27; Eskom News No.56/16 April 1986:5)

 A mining disaster occurred in the Northern Free State at the Coalbrook coal mine on 21 January 1960. This had a major impact on ESCOM's power stations and a temporary reduction in electricity supply in the Rand-Witbank area became unavoidable from 13 to 19 March 1960. Emergency measures were introduced to bring coal by rail and by road to the power stations immediately affected. Coal from Cornelia colliery was railed to Taaibos Power Station, as Witbank coal proved unsuitable there. Witbank coal was used at Klip and Vereeniging. Over this period coal received at Klip had a calorific

value over 10 200 Btu/lb [23,7 MJ/kg]. This was the highest during the operating life of Klip. The lowest calorific value received was 18,35 MJ/kg, in the year 1983. (ESCOM Annual Report 1959:9; ESCOM Annual Reports-Tables of Power Station Operating Statistics)

 
 
  Ash dumps
 
 
 ASH DISPOSAL
 

Each of the three ash handling plants comprised a system of high velocity water sluiceways, ash and water sumps, a telpher grab and an ash-bin. From these bins the ash was transferred into the buckets of the aerial ropeways for conveyance to the dumps. The total amount of coal consumed over the 50-year lifespan of the station amounted to 84,5 million metric tons. With an ash content of 20 to 25%, the amount of ash accumulated resulted in the three dumps growing to a considerable size. After the po​wer station was closed, the ash dumps were taken over by Roshcon, a division of Eskom Enterprises. In 2004, the ash was being used for making building bricks and was expected to take about 15 years to remove completely. (Andrews 1937:23; Pickles and Trelease 1940:7; Simunye Power Stations)

 
THE KLIP TRAINING CENTRE
 
STAFF
 

In 1945 negotiations started which lead to the expropriation of the VFP and the purchase by ESCOM of its assets. This took place on 1 July 1948. Klip Power Station had always been owned by ESCOM, but had been operated by the VFP on behalf of ESCOM. The VFP staff members were transferred to its subsidiary, the Rand Mines Power Supply Company, up to 31 December 1948. From 1 January 1949 staff members were formally transferred to ESCOM. During the early 1980's the staff complement consisted of about 1000 employees. At the closure of the power station the staff members were either transferred elsewhere in ESOCOM or took retirement. (ESCOM Golden Jubilee 1923-1973:21; Conradie and Messerschmidt 2000:105; ESCOM Brochure - Klip, Vaal & Vierfontein Power Stations.

 
 
Past power station managers of Klip Power Station. From left: Messrs Arthur Moss, George Baird,
Harold Williams, Ian McRae (Senior General Manager), and Ray Chapman who was the last manager at Klip.
 
  
 CLOSURE AND DEMOLITION
  

During the 1980's Eskom had been commissioning its new giant six-pack power stations. But due to a decrease in the rate of growth in the demand for electricity in South Africa, Eskom began to experience a surplus of generation capacity. The older and less efficient stations were thus no longer required. Colenso was closed down in 1985 and Klip in 1986. These were the two longest-serving stations at the time. (Conradie and Messerschmidt 2000:259-260)

KLIP1.jpg
Sharing a belly laugh the two old-timers from Klip T R Fenwick (left) and Harry Allen, both of whom were maintenance engineers at Klip


50 years’ loyal service the old lady retired.  Her honorable guests had started to arrive.  She’s made a special effort to make them feel at home.  The festive mood was highlighted by colorful bunting in blue and yellow, while the happy sound of a brass band blended with the cheerful bustle of those present.  There were several familiar faces.  Some had made a special effort to be present.  Among them were, Mr Baird, one of the previous power station managers.  Another was Mr Cyril Jinks and established Escomite, as well as Mr Harley and Mr Moss.  They all knew all about the old lady’s whims and fancies.  Messrs T R Fenwick, Harry Allen and George Terry were also mingling with the guests.  Ray Chapman, her last manager was one of the guests of honour.

KLIP2.jpg 
 Making preparations to close the shut-off valve, while the guests look on
 

ESCOM’s General Manager, Ian McRae also knew her well.  He had worked for her for six months and entertains the rest of the guest with incidents from the good old days.   Then finally, it was the time to say goodbye.  The VIP guests moved to the power station where they assembled at turbine five. It was the turbine which Lionel Oëhley started up 50 years ago.  Today it was his privilege to switch it off.  The engine room was fitted with a high pitched whistling sound.  The turbine operated at 3 000 revolutions per minute.  In the control room Ian McRae and Ray Chapman were ready to bring it to a standstill for the last time.

KLIP3.jpg
Ian McRae pays tribute to Klip and all those who worked there, while Ray Chapman listens pensively


The revolutions slowly dropped.  The old lady was losing her strength, she lets off her last steam, while Lionel Oëhley assisted by Japie Brits, Herman van Rooyen, Chris van Oordt and Konnie Verwey turn off the steam valves.  Some of the guests gave the turbine a last loving stroke before they walked away.  At the entrance they looked back.  Her vast engine hall is quite, but the turbine was still shimmering in the daylight.   

It took 25 months to build Klip power station.  Plans for the building were approved in 1933 between the commission and their engineers in London, with the co-operation of the consultants Merz and McLean.

Excavations began in the first week of June 1934 and 21 months later, on 10 March 1936, the first 33 000 kW engine and two boilers were put into operation. During the following four months the rest of the sets, with boilers of the same size, started generating power.

A power station with a development capacity of 132 000 kW was built and started generating power within 25 months.  In comparison with other power stations, the building and operating of Klip power station could be regarded as a world record.

In 1940 Klip was the biggest coal driven power station in the southern hemisphere with possible the biggest delivery capacity by any coal driven station in the world.  The low cost of developing power has never been equaled by a similar station.  In 1953 the Springfield coal mine, which served as a source for Klip, was exhausted.  Since then approximately 5 000 metric tons of coal had to be transported daily to the power station over a distance of 100 km.


The formal closing ceremony of Klip Power Station was held on 26 March 1986, when Lionel Oëhley shut down the last turbine. Fifty years previously he had started up the first turbine. He had worked at the station for 42 years. His wife, Florence Oëhley, said they had always lived in the same house at Klip. Present at the closing ceremony were Mr [later Dr ian McRae, Chief Executive Officer of ESCOM, and several past Power Station Managers including George Baird, Harold Williams, Arthur Moss and Ray Chapman. Dr McRae had worked in the control room at Klip for six months after qualifying as an engineer in 1953. Ray Chapman joined ESCOM in 1956 and became Assistant Resident Engineer at Klip in 1970 and then Power Station Manager in 1975. He was the last to hold this position at Klip. (ESCOM Megawatt No.57/Dec. 1979:25; ESCOM News No.8/Jun. 1983, No.22/Jul. 1984:5; No.56/16 Apr. 1986:4-5)

KLIP TOWERS.jpg

Explosives demolished the cooling towers during 1987. These were the first cooling towers to be built at an ESCOM power station and the first to be demolished. The power station plant and equipment was disposed of as scrap, the buildings were totally demolished and the land rehabilitated. Only the workshops and township remain. In 2004, the land was still owned by Eskom. (ESCOM News No.80 June 1987; Simunye Power Stations)

 
   Aerial view of th​e retirement village
 
  

When the staff housing became redundant after closure of the power station, rather than demolish the buildings, which were fundamentally still sound, Eskom decided to put them to good use and improve the lot of its pensioners at the same time. As the township was not a proclaimed municipality or suburb, the houses could not be sold. The estate included 129 houses and single quarters for 73 employees, as well as other facilities. The township was transformed into a proper retirement village with facilities for local management, medical care, catering and recreation. It was well sited near to Vereeniging and the Reef, where tenants could enjoy the benefits of the city together with the peace and the amenities of the Vaal River. Accommodation was to be administered jointly by the tenants and the Eskom Foundation, an organisation formed specifically to provide housing and related facilities for Eskom pensioners. Mr Lood Rothman, Eskom's Senior General Manager, handed over the housing estate for development as a retirement village at a handing-over ceremony in June 1988. At the ceremony, Mr Louis Roberts showed off the gardening trophy that had been won by Klip. In later years the Eskom Foundation withdrew participation, and the staff of Lethabo Power Station managed the township. (Eskom News No.107/July 1988:3)

BIBLIOGR​APHY
 

Andrews WO: Notes on a performance trial of a boiler at Klip Power Station. In: The Journal of the South African Institution of Engineers, September 1937

  •  Conradie SR and Messerschmidt LJM: A Symphony of Power - The Eskom Story - Chris van Rensburg Publications (Pty) Ltd, Johannesburg, 2000
  •  Electricity Supply Commission: Annual Reports,1948-1984
  •  ESCOM Brochure - Klip, Vaal & Vierfontein Power Stations
  •  ESCOM: Golden Jubilee 1923-1973
  •  ESCOM: Megawatt 1966-1982
  •  ESCOM News / Eskom News 1982-1993
  •  ESCOM/Eskom: Statistical Yearbooks, 1985-1990
  •  Kanthack FE: Inaugural Address. In: Journal of the South African Institution of Engineers, August 1938
  •  Pickles V and Trelease JS: Klip Generating Station - A General Description. In: The Transactions of the South African Institute of Electrical Engineers, May 1940
  •  Troost Dr N and Norman HB: Electricity Supply in South Africa 1909-1969. In: The Transactions of the South African Institute of Electrical Engineers, September 1969
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