Visit to Eskom’s Palmiet Power Generation Installation: February 2015

Into the Belly of the Beast with the Cape Centre courtesy of Richard, Vanessa and Eskom.

ESKOM is South Africa’s power utility and came into being in 1923 as the Electricity Supply Commission or ESCOM. In 1987 ESCOM became ESKOM, a name which the company has retained to the present. Eskom is currently responsible for the generation of about 95% of the electricity generated in South Africa and about 45% of the electricity used in Africa. Lynnette and I were very early so we headed for the Orchard Farm Stall outside Grabouw for a light breakfast.

Top row, (l to r) & 2nd row (l):  On the R300  headed for Grabouw. 2nd row (r) Sir Lowry's Pass. 3rd row (l & r) The Orchard Farm Stall outside Grabouw
Top row, (l to r) & 2nd row (l): On the R300 headed for Grabouw.
2nd row (r) Sir Lowry’s Pass.
3rd row (l & r) The Orchard Farm Stall outside Grabouw

Eskom laid on tea coffee and eats for our group at the Visitor’s Centre of the Palmiet Pumped Storage Power facility near Grabouw in the Elgin Valley. That was followed by a presentation from our very competent guide, Vanessa, in which she first explained the differences between Eskom’s different power generation units and gave us some general background on Eskom. She went on to give us a detailed explanation of how the Palmiet plant functioned and emphasized the difference between a conventional hydroelectric system and a pumped storage system such as Palmiet.

Top left: The visitor's Centre at the Palmiet Pumped Storage Scheme . Top right: Even ESKOM need some serious barbed wire protection. Bottom left: The road down to the power plant with a nice view down the beautiful Elgin Valley. Bottom right: The power plant and its distribution facility.
Top left: The visitor’s Centre at the Palmiet Pumped Storage Scheme .
Top right: Even ESKOM need some serious barbed wire protection.
Bottom left: The road down to the power plant with a nice view down the beautiful Elgin Valley.
Bottom right: The power plant and its distribution facility.
Why is only this one section of the barbed wire fencing rusted?
Why is only this one section of the barbed wire fencing rusted?
Hans se Kop, which was the scene of Auke's meteor expidition recently with, Wendy, Alan and Rose.
Hans se Kop, which was the scene of Auke’s meteor expidition recently with, Wendy, Alan and Rose.

The latter is always situated on a waterway connecting an upper and a lower reservoir and not on a natural waterway or river. The Palmiet generator is situated between the Kogelberg Dam on the Palmiet River and the Rockview Dam higher up on the slope of the mountain. Palmiet can supply electrical power during periods of peak demand, or in an emergency, by allowing water to flow from the Rockview Dam to the Kogelberg Dam through two reversible generator- motor/pump- turbine sets. During periods of low energy demand excess generating capacity is available and the same water is pumped back up from the lower to the upper reservoir. In addition the upper reservoir is also connected, via an extensive set of pipes and channels, to the Upper Steenbras Reservoir, which is one of the dams supplying the City of Cape Town with water. The Palmiet system augments Cape Town’s water supply by around 25 million cubic metres (m3) a year. One cubic metre is 1000 litres and an Olympic swimming pool contains 2,5 million litres of water. So, the Cape town water supply receives the equivalent of 10 000 Olympic swimming pools from the Palmiet pumped storage scheme.

The main wall of the Kogelberg Dam which is both the source of water for the system and also the receiver of the water flowing back down from the Rockview Dam
The main wall of the Kogelberg Dam which is both the source of water for the system and also the receiver of the water flowing back down from the Rockview Dam
The top of the 61m surge tank as sen from the power station.
The top of the 61m surge tank as seen from the power station.
The surge tank on the left and the northern aspect of the Rockview Dam as seen from the N2.
The surge tank on the far left and the northern aspect of the Rockview Dam as seen from the N2.

The Palmiet generating system can be brought on stream in about three minutes. In comparison, a coal-fired system requires eight hours or more before it can supply power from a cold start-up. Power generated here can be sent down lines to the Bacchus substation near Worcester and to the Stikland substation in Cape Town.

The distribution facility where one line goes to the Bacchus substation near Worcester and the other to the Stikland substation in Cape Town
The distribution facility where one line goes to the Bacchus substation near Worcester and the other to the Stikland substation in Cape Town
A closer look at the distribution yard where the power from the generator comes in via those three large stainless steel conduits and is then converted in the  yellow transformer system to the correct  voltage for distribution.
A closer look at the distribution yard where the power from the generator comes in via those three large stainless steel conduits and is then converted in the yellow transformer system to the correct voltage for distribution.

After more refreshments and a closer look at all the informative material on the walls of the well maintained display area, we followed Vanessa down to the power generation facility by car for a closer look at this eco-friendly setup.

The initial impression at the power plant was that of a rather inconspicuous building with an attached section that, judging by the spider web of wires, masts and pylons, clearly represented something electrical and very much hands-off. However, to parody an old television commercial for Cremora Coffee Creamer “It’s not what’s on top, it’s what’s down below” because about 60 metres below us (that is just over 18 storeys) are two pump-turbine generator-motor sets that can each turn out 200MW. When running in pump-mode these two units return water to the Rockview Dam at a combined rate of 126 m3 per second. You can check my calculations, but that converts to filling an Olympic swimming pool in less than 20 seconds!

Our group led by the intrepid Vanessa in the blue outfit
Our group led by the intrepid Vanessa in the blue shirt on the left.
The ground level machine hall with the huge overhead crane. The wall in the foreground guards the entrance to the machine shafts.  Not the size of the figures for scale
The ground level machine hall with the huge overhead crane. The wall in the foreground guards the entrance to the machine shaft. Note the size of the figures below the crane for scale
The crane's vital statistics
The crane’s vital statistics
The list of participating companies involved during the construction of the plant
The list of participating companies involved during the construction of the plant

The ground floor machine hall, with its huge crane that can lift a whopping 360 tonnes from a depth of 65 metres, looks like an aircraft hangar at first glance until you notice the two circular walled areas. Approach them with caution if you have even the slightest tendency to vertigo, because when you look over the waist-high wall into the 23 metre wide pits, the first stop for your gaze is 18 storeys down where you can see the giant blue inlet valve. Bear in mind that these shafts actually extend a further 20 metres below that level to the drainage pumps. For comparison the Media-24 building on the Foreshore in Cape Town is 93 meters high so, if you knock the top four storeys off that building, you have the total depth of each of the two machine shafts at the Palmiet pumped storage facility.

Looking down the machine shaft from the ground floor level. The round red object is the top of the generator unit and the blue object on the left is the inlet valve
Looking down the machine shaft from the ground floor level. The round red object is the top of the generator unit and the blue object on the left is the inlet valve. On the left are the three conduits bringing the power up from the generator to the transformer and distribution system outside.
A composite photograph showing the machine shaft and the power conduits, attempting to convey the size & depth of the setup.
A composite photograph showing the machine shaft and the power conduits, attempting to convey the size & depth of the setup.

Vanessa led us down into the belly of this beast, divulging the one fascinating fact after the other as we dropped lower and lower. On the floor of the machine hall it was quiet and there was no detectable vibration, but as we went deeper and deeper into the concrete and steel entrails of the beast, the noise levels rose, earplugs were issued and the vibrations in the walls and floors increased: the beast was not asleep and I was feeling distinctly like Bilbo Baggins creeping up on Smaug. In the lower passages watertight doors appeared on which the signage clearly warned that they shut automatically and without warning in the case of an emergency. Vanessa reassuringly pointed out flights of steel staircases vanishing upward into the glare of fluorescent lights. I could not but wonder exactly how fast one could run up those stairs with the water hard on one’s heels.

This is the escape route.  Imagine running up here with water rising fast behind you.  How fast would one have to run?  Well, according to Vanessa it is coming into the building at 60 km per hour!
This is the escape route. Imagine running up here with water rising fast behind you. How fast would one have to run? Well, according to Vanessa it is coming into the building at 60 km per hour!
Check out how deep we are.  The abbreviation MASL mean "metres above sea level". I did not find the notice at bottom right a very reassuring one.
Check out how deep we are. The abbreviation MASL mean “metres above sea level”. I did not find the notice at bottom right a very reassuring one.
Please note the notice to the right of the door.
Please note the notice to the right of the door.
This monster is what controls the water entering the turbine.  It is difficult to convey scale but look closely it is really huge.
This monster is what controls the water entering the turbine. It is difficult to convey scale but look closely it is really huge.
Ross Bauer looking up the Machine shaft from the level of the top of the generator.
Ross Bauer looking up the Machine shaft from the level of the top of the generator.

The huge rotor of the pump-turbine generator-motor spinning at 300 rpm a few meters away from one’s face as it churned out its 200MW, was very, very impressive, even for the less mechanical minded members of the group. I, however, could hardly take my eyes off the giant inlet valve. It just sat there, big, blue and quite ugly but that silent immobile monstrosity was all that stood between us and a very sudden, very watery grave. Just bear with me while I bore you with some more figures. At the Rockview inlet high above our heads, water is admitted at a rate of 185 m3 per second into a tunnel 6.2 metre wide. The tunnel diameter is reduced in steps: first to 5.4 metres, then to 3.9 metres and finally to 2.6 meters where it enters the generating complex. Now consider the vertical drop from the Rockview Dam to the generating complex and the reduction in conduit diameter as well as the fact that, according to Vanessa, the water is travelling at 60 km per hour when it reaches the valve. All of these factors must add up to an enormous pressure and definite case of German engineering when one needs it most. Perhaps you also now understand why I found the valve so fascinating and also why I wondered how fast Lynnette and I could negotiate those steel steps.

Face to face with the beast spinning at 300 rpm and this close you can feel the air current it creates as it spins and the noise is quite overpowering.
Face to face with the beast spinning at 300 rpm and this close you can feel the air current it creates as it spins and the noise is quite overpowering.
The vital statistics of the generator unit
The vital statistics of the generator unit
The vital signs of the spinning beast are monitored here and up in the control room many metres above our heads
The vital signs of the spinning beast are monitored here and up in the control room many metres above our heads
These huge steel arteries carry the power up and out of the machine shaft to the distribution yard.
These huge steel arteries carry the power up and out of the machine shaft to the distribution yard.

To deal with flow variations and pressure fluctuations, there is a surge tank positioned shortly after the start of the downhill watercourse. This structure is a cylindrical free standing structure 61 m high and 21 m in diameter which instantly relieves any variations in the pressure of the downstream system. The tower and the northern aspect of the Rockview Dam are both clearly visible from the N2.

After saying goodbye to Vanessa we headed back to Brackenfell. To left: A view of the iconic Helderberg as we descended Sir Lowry's Pass. Top right: looking out over False Bay toward Gordon's Bay Bottom left: View across the Strand and toward Cape Town
After saying goodbye to Vanessa we headed back to Brackenfell.
To left: A view of the iconic Helderberg as we descended Sir Lowry’s Pass.
Top right: looking out over False Bay toward Gordon’s Bay
Bottom left: View across the Strand and toward Cape Town

On a final note, the Palmiet pumped storage scheme has an impressive safety record and an even more impressive conservation record. The plant is situated in the Kogelberg Biosphere Reserve, designated as such by UNESCO’s Man and the Biosphere Programme in December 1998. The Reserve comprises the Kogelberg Nature reserve, the entire coastal area from Gordon’s Bay to the Bot River vlei and inland to the Groenland Mountain and Grabouw, a total area of some 92 000 ha. Palmiet is the recipient of several prestigious awards.

In 1987 Palmiet was presented with the award for the Most Outstanding Civil Engineering Achievement by the South African Institute of Civil Engineers.

On completion in 1988, Palmiet won the Environmental Planning Professions Interdisciplinary Committee Award for integrated environmental planning and management.

In 1997 Palmiet was presented with the Conserve Award for outstanding achievement in effective conservation and sustainable utilization of the environment to ensure a better quality of living for all South Africans by the South African Minister of Environmental Affairs and Tourism.

In 2003 Palmiet was awarded the Blue Planet Prize by the International Hydropower Association.

Palmiet has consistently been rated a five star performer in industrial safety by the National Occupational and Safety Association (NOSA) and is the holder of the NOSCAR, NOSA’s most prestigious annual achievement award.

The list of concervationorganizations and educational institutions involved during the construction of the plant
The list of conservation organizations and educational institutions involved during the construction of the plant
Award for the Palmiet project
Award for the Palmiet project

With all these fine achievements it is inexcusable that ESKOM has slipped to the levels of inefficiency we experience at present. Read these two documents clearly displayed in the Visitor’s Centre and compare them with the actual situation as we South Africans experience them. It is totally farcical.

ESKOM is sadly unable to meet its own objectives and achieve its set goals
ESKOM is sadly unable to meet its own objectives and achieve its set goals