A seven metre diameter butterfly valve

I can’t be kept away from work. I don’t know if that’s a pity or I’m just weird. Then again, it’s not everyday that you get to see a hydroelectric power station in a drought-ridden country. It also awakened that technical side of my brain which has been lying dormant for a few days.

Built along with the dam is the Gariep Power Station. This is one of two major hydro stations in the country and on the Gariep River. There are four micro-hydro stations that do exist in the Eastern Cape – namely Collywobbles, Ncora, First Falls and Second Falls, but these are used for grid-stabilisation and are not under the control of Eskom Generation but rather under Eskom Distribution.

At present, the Gariep Power Station uses four generators rated at 90MW each to produce 360MW of power with the head of around 55m. The generators are presently being refurbished and by next year, this station will be generating 440MW. The Vandekloof generators will still be larger, but there are only two there. This value is impressive when one sees the dimensions of the dam wall. We won’t compare it to the 22000MW of Three Gorges…Getting into the station was pretty easy – well for me at least! With prior arrangement, the staff will happily take you around the station. No photographs are allowed though.

I get to the dam slightly early and attempt to get into the power station. This proves a problem seeing that there are two gated entrances. I’m a bit puzzled but I choose the gate on my right. Actually, I know that this entrance is the wrong one but I take it anyway. I obviously haven’t learnt my lesson after encountering the shooting range a few days earlier. Luckily, I don’t end up in some experimental farm but I do get a great view of the dam wall. Viewing it from a platform hundreds of metres away takes away the beauty of the scale of this wall. Coupled with the colossus of water it holds back, the wall looks pitifully small. That is until you see it up close! This wall is not solid but has a series of tunnels embedded in it. One such tunnel is so huge that there is an annual church service that is held within it. One can arrange tours of such tunnels if one wants.

At around 12h00, I meet a distinguished gentleman named Lucas Van Heerden. He has been working at this plant for many years and stays in the nearby hamlet of Gariep Dam (a town!). The town reminds me of a minor holiday town on the KwaZulu-Natal South Coast – albeit, a MUCH more laidback version of it. The station is pretty small and has the dimensions of maybe a single generator-set in a coal-fired station. On the ground level are huge circles painted onto the floor. Underneath each lies a vertically-mounted 90MW beast. The diameter of each is roughly 10m. That’s five of the tallest people you know stacked on top of each other. Pretty huge I tell you…

Taking the stairs down, I encounter the turbine. The hydro plants in South Africa, due to the small size of these plants, are used for peaking power. Simply, this means that when South Africa requires vast amounts of electricity, these stations run. When the load requirements drop, the station is switched off. Hydro stations are built for this purpose because of their very nature – liquid water turns the turbines. Without water, the turbines don’t turn. If these don’t turn, no electricity can be generated. This principle is built into the mechanics of the system so the absence of water does not cause damage to the system. Compare this to a coal-fired station – steam is used to turn the turbines. Steam must be generated by burning coal to heat up water to the required temperature. Water takes a while to heat up hence; coal needs to be burnt for quite a while before optimal conditions are reached. Cooling is then needed to extract the most energy out of this steam. Even with this simplification, one can see that this process is rather complex. Compare this to: Open sluice gate; run water through turbine; make power. One can see that hydro plants are much more suited to the peaking criteria!

As I walk into the room leading to the turbine (the power station was off), I encounter the tailrace pipes that transport the water to the turbine. At this point, Lucas explains to me what I see. When the station is not being used, water must not be let through to the turbine. This is controlled by a valve – a seven metre diameter butterfly valve at that. I look at shocked. I’m in shock and awe and my mouth can’t close because, well, it’s so freaking huge! Lucas sees me and gives the knowing look of, “Ja, I know.” I love being an engineer.

The station also has no control room. All controls of the station are handled via National Control. All alarms are, likewise, sent directly to National Control. If there are any faults, an operator sitting at national control calls up an engineer or technician and the fault is sorted out. Then again, this station maybe gets two alarms per week – something that should trickle through to coal stations. Okay, enough with the words, this is just awesome!

Lucas and I chat for a while about peaking, the new refurbishments of the generators, the new coal-fired stations and the role of renewables and the current financial situation of Eskom and the world in general. We also talk about a pending C&I upgrade to the plant which would render all the employees, which have been working there since the plant was commissioned, useless. The joys of technology…I bid Lucas farewell and leave the station extremely impressed by this great technology.

Hydroelectricity is loved and loathed by various green energy aficionados. The one school of thought sees the damage that dams do when built. Whole ecosystems are wiped out by building a simple dam. The Narmada Valley in India is a prime example (so are all the new dams in China.) The other harps on about the carbon-free energy that we get from this type of power generation. I guess the Gariep is special in this case – the ecosystem around the Gariep is thriving and provides a haven for many endangered species. Then again, most local Nature and Game reserves are built around artificial bodies of water. Without these, most of our flora and fauna would be decimated. Whilst doing this, the station provides the non-industrial electricity needs of several provinces without doing any harm. I wonder if the damage done whilst constructing this dam is offset by the role it’s played in conserving our natural resources…

Chasing the sun around the Lake District

For some odd reason, the route around the Gariep Dam is called the Gariep Lake Route. As far as I know, a lake is a natural body of water whereas a dam is enclosed by a dam wall made of some sort of structure – be it man-made or made by beavers in North America. Whatever the reason, the drive around the dam is one of the most amazing drives in South Africa.

In 1971, a marvel that showcased South Africa’s engineering skill was opened. We’ll forget that the project was given to a French company for a moment as I tell you about the Hendrik Verwoed Dam (now called the Gariep Dam) – built in the Ruigte Valley; the dam wall stands 88m high and is almost a kilometre in length. The amount of enclosed water is staggering. Think of the distance from Amanzintoti to Verulam. Now think of how far apart Durban is from Pietermaritzburg. The mighty Gariep Dam is larger than this…

The round trip is a “tourist” circuit consisting of the R701, R390 and the R58. The circuit is quoted as being 134km long – I honestly feel it is much longer. The road is spectacular. It is a perfectly tarred masterpiece stretching out to the horizon in this most amazing land. The sleeping Free State greets the remnants of the magestic Maluti. Together, they dance and meet in this beautiful valley – a valley now that is pivotal in allowing millions of South Africans to quench their thirst and live.

The road is just great. I’ve thought long and hard on ways to describe it but I just can’t do it justice…The route starts outside Smithfield on the 70km or so drive to Bethulie passing the Tussen-die-Riviere Nature Reserve. On the way, I was greeted by maybe five potholes and probably the same amount of cars. Climbing over each hill is a signal for you to hold your breath. Emerging on the horizon is beauty that you have never experienced before. Go over the next hill and the beauty is outdone as the giant snake of the Gariep pulls you closer and closer. I’m sure those stunning posters of roads leading into mountains are taken here and not at the foot of the Appalachians and Rockies! Although a day earlier, I felt scared because of what unknown fears lurked on the sides of the N12 outside Kimberley, the fear of this road was far greater. In all its beauty, this road defined “alone…” A cry for help goes unnoticed and unheard. It is here where you truly experience yourself and your reality.

The Gariep has this natural sense of mystery, power and greatness. Starting in the Drakenberg, this river, also know as the Orange, is the lifeblood of South Africa. Downstream of the Gariep is another mega-dam, Vanderkloof, home to South Africa’s largest hydroelectric scheme. Even more downstream is the wonder of the Augrabie Falls. Further downstream is the river mouth at Alexander Bay. Here, the mighty Gariep releases her diamonds into the Atlantic. Visit Alexander Bay and you’ll see how important these diamonds are to people…

Anyway, the Gariep is home to an ambitious project. South Africa is a drought country – the water we have is precious and not abundant. Not a year goes by without warnings (that we don’t heed) about South Africa having serious water shortages within a few years. The Gariep has a water tunnel on its eastern shores that connects to the Great Fish River that nourishes the Eastern Cape. Its use is similar to the Lesotho Highlands Project at Sterkfontein Dam in KwaZulu-Natal – when water is sparse; it is transferred from the Gariep to the Great Fish to provide the province with water.

I’m a sucker for dramatics and I was hoping to experience awe at the first sight of water from the Gariep. This, obviously, never did happen. After a quick stop in Bethulie to offload, I set about remedying this by embarking on another infamous sun-chasing mission to capture the sunset over the Gariep. My destination lay 60km away on the south-eastern banks of the Gariep at a hamlet named Oviston. The R-roads are infamous for their lack of shoulders, cat eyes and fences. With knowledge of the cow incident still pretty fresh, I speed on hastily as the sun falls. It light bathes the land in a lazy orange that intensifies as the sun retreats more and more. I push on…

I reach Venterstad and soldier onto Oviston as the orange glow deepens. Looking back, darkness encroaches. I start to panic and wonder if I will make it in time. I (obviously) have never been to the Gariep before and I have no knowledge of the terrain that I will encounter at Oviston. I wonder what the view would be like and if this mad trip was worth it. I reach the town and the waters edge. On one side of the dam, the sun kisses the horizon with its most intense shade of orange. On the other is nature’s most beautiful view…

I sit on the rocky banks, perched on a rock gazing at this site. A heron calls from the distance as the sun extinguishes over the Gariep. I smile 🙂

I linger. In actual fact, lingering could spell my death. I have a half an hour drive back to Bethulie on a road strewn with cattle and untold creatures of the dam. Obligatory on all routes travelled at night is the car without lights. It amazes me how people travel with minimal vision. In this wilderness, the hazards multiply. I easily pass them and approach the Bethulie Bridge. I am home and safe – a relief. However, the Bethulie Bridge has something in store for me…