Sunday, April 21, 2024

Load shedding – A look at the facts


File:Rolling black outs of up to 8hrs in duration continue to plague Zambian

Zambia has had some problems with the electricity supply recently. Why?

Hydropower is a natural source of energy, clean and dependable, and very suited and able to provide continuous supply 24 hours a day provided that there is sufficient water available. For professionals in the industry, this is known as “base load”. Alternative energy sources such as solar and wind have an inherent problem which is inconsistent supply, often failing when it is most required such as at night when the Sun is not shining or the wind is not blowing.

The other options, such as coal and gas are environmental polluters of note, and with global warming, are becoming a serious threat to our future, they deserve to be examined with great scrutiny to ensure the costs of the environmental damage they cause is realistically assessed. Zambia is blessed with rich natural resources, of which massive amounts of water is a major one. How can we effectively harness these advantages?
Most of our power comes from hydroelectric generating facilities, which were built before Independence or in the years immediately after. Has anyone given serious thought to how the rising demand for power in Zambia will be met by future generations? Or will our children be doing their homework by candle light?

Zambian electricity supply is heavily dependent on hydro, and this is because it is such an abundant and versatile source. But to ensure it will be used most effectively in the future, we need to critically examine how we are using it now, and what we can do to maximize its positive aspects in the future.

Kariba is a good starting point.

For more than fifty years, these installations have served Zambians well. So much so, that we have become complacent and over reliant on these facilities to the extent we have taken them for granted – until load shedding arrived!…. Now, with a situation that is a serious impediment to our economic development, loss of revenue to the main power provider, and a huge extra cost to businesses that have to purchase and run expensive generators, people have suddenly woken up to the fact that economic progress is intrinsically linked to power supplies.
What can be done?

Currently those responsible are regurgitating old solutions that were proposed over forty years ago. Kafue Gorge Lower was even commissioned in 2011 and then cancelled. Batoka Gorge has been the focus of numerous investigations since 1972, and now suddenly become urgent. The current deficit of electricity has been blamed on climate conditions, specifically the droughts of dry years. Rather than being a problem caused by Nature, this looks more like a problem caused by those responsible taking their eye off the ball!

Practical solutions

As we have taken Kariba as an example, let us look at other possibilities in more detail that may have some merit. The water that drives the turbines at Kariba comes to that point as a result of rainfall. Where does that rain actually fall? Below is a map of the catchment area that supplies Kariba with its water.

The area outlined in green are the parts of Zambia and Angola that contribute to the total water flow received and used to generate power. Note that the central part of Zambia is the Kafue river catchment area, and does not flow into Lake Kariba! The Kafue River does join up with the Zambezi River, but that junction is much further downstream past Chirundu and so contributes no water to Kariba.
So, if the limiting factor to the amount of electricity it is possible to generate at Kariba is the amount of water received by rainfall in the catchment area, is it possible to increase this amount by our intervention? Obviously, it will have to come from some other catchment area. This is not as unrealistic as it seems at first glance. In the US about 90% of the water used in California comes from water diverted from other catchment areas! Water diversion is a very common way of taking water from where it is in surplus to areas where it is in deficit.

So where to look for more water?

Here is a huge catchment area that contributes no water to the Kariba dam. Can it be utilized? This is the catchment of the Kafue River. It is used to generate power at the Kafue Gorge hydropower facility, but is it using it all? Is it using it efficiently? When there is too much, what happens to the excess amount? Can the surplus be used in a cost effective way somewhere else?

Let us look at this more closely. What will determine if this is possible? Firstly, water does not run uphill! To be possible, Kariba must be much lower than the Kafue River. Is it?
The level of Lake Kariba at full supply is about 1700 feet above mean sea level. The level of the Kafue River at the point where it is possible to divert it is 3000 feet above mean sea level – more than enough to ensure a good flow of water!
Secondly, is the geography suitable for the construction of a canal to divert the water? How much will it cost to construct? A cursory glance at the topography of the area shows it is eminently possible and very feasible.

So what advantages will such a scheme bring?

As the infrastructure to generate hydropower is already constructed and installed at Kariba, it will be able to use this capacity without installing additional generating capacity. This includes the “peaking turbines” that have recently been commissioned.
It would also create the capacity to use the diversion canal for irrigation purposes
What about Kafue Lower Gorge?
Obviously, this would divert water from the generating capacity of this power station. Does this affect it? An unanswered question!
Can the experts please advise us on the practicalities of this alternative?
By Adrian Piers


  1. Good thinking google snowy mountain scheme in australia…back in depresssion still used…. used the unemployed and provide water for energy and farming..
    Well put together article

    • But why were people despising mulyokela when proposed the idea of putting up pipelines from other water sources into kariba? Mulyokela must hear this, he already has copyrighted this idea.

    • Plagiarism! this is my ideas. Am arresting this Adrian foo1 and charge him with plagiarism. He must learn to acknowledge.

    • Good practical idea for long term solution. wont be surprised if somebody copies and paste it for 2021 campaigns. Energy ministry should have an interest in this masterpiece article. well researched.

    • “For more than fifty years, these installations have served Zambians well. So much so, that we have become complacent and over reliant on these facilities to the extent we have taken them for granted”


  2. This is the innovative thinking that Zambia needs!

    But what about Zimbabwe? Will they be getting the extra water for free? We need to make them pay 50% of the costs of this as they are using 50% of the water in Kariba.

  3. Very good ideas that deserve to be taken serious by the government. But for African leaders including Zambia, It’s always going to be business as usual. If the president cannot get a cut from a project, then it’s not feasible. The other problem is our leaders can not plan beyond a year. They want something that will bring them instant benefits. That’s all. It’s a very hopeless situation in Africa with very few exceptions such as Botswana, Namibia and South Africa.

  4. South Africa has a river transfer scheme called the Lesotho Highlands scheme that moves water from the Orange river to the Vaal river and provides Joburg with most of its water.

    Sure they can help with something like this.

    • But what is the discharge of that transfer scheme? Kariba has a volumes in billions cubic meters, so will require draining the entire Kafue river’s 320 m3/s. What happens to aquatic life downstream? There is a big difference. In line with international best practices, more than 70% of original discharge needs to be maintained after diversion. U will can only divert less than 30% of the original discharge in order to not to impact aquatic life downstream. The volumes matter. see my comment below…

  5. The idea sounds ok theoretically. But there are serious environmental, financial and practical consequences to consider. The average discharge of Kafue river is about 320m3/s . There are 6 machines at Kariba on Zambian side and each machine requires about 200 m3/s to generate 180 MW of power. Even diverting 100 m3/s will heavily impact on the aquatic life from the point of diversion. in short this can not be approved by any sane Environmental authority. Besides a project of that magnitude will require billions of dollars that can not be funded by GRZ. U will need the help of international financiers. One of the key requirements for the likes of world bank, Africa development bank etc. is to ensure minimum environmental impact. from practical point of view the canal required for say 200…

  6. Kasolo mune don’t mind those shooting down your idea, they did the same to mulyokela’s, today they want to look like geniuses, this idea of pulling water from other sources into kariba is mulyokela’s baby.

  7. We find reasons NOT to do things rather reasons to DO . Negativity stops prgression. Zambians believe in ourselves. Why do we have an inferiority complex. Focus focus on projects and the future not on petty polictics

  8. Kasolo is obviously NOT a problem solver.Typical of Africans.Afraid of solving problems and leaving them to the whites.Grow up for once.

    • You have not even evaluated Kasolo’s statement.
      It’s a fact that by international and ecological reasons, you cannot divert more than 30% of a river. So building a canal for just under 30% of Kafue is just nonsense that cannot be approved by anyone with money. In any case, the Lake Kariba is an endangered structure not worth further investment of that magnitude. It can collapse any time.

    • @Kambe, I don’t think that’s the way to go! Kasolo is not being negative in his post but simply putting points across that require consideration by people with well vested knowledge about these issues. We need health debates and not name calling or bad mouthing. Adrian has pieced together a well researched article that needs serious consideration from the experts/powers that be. Look at the post from the Analyst below! This is what we need on sites such as this. Not politics masiku onse!

  9. Well said Kasolo Lubemba, further to that – it would be a bad idea to divert water from the Kafue river before its used for power generation as indicated on that map. To be efficient the water can only be diverted after the lower kafue power station. Even then how much benifit will that 30% water diversion bring. Are we not concerned that our Uranium from Lumwana is being utilised to develop other countries energy systems and not ours???

  10. This blog seems to be active.. can anyone tell me why a $30million contract with Gridbow from Sth Afr. for solar for farm blocks is going through Agriculture Ministry rather than Energy Ministry

    • Have you for once forgotten that Dora ”long fingers” Siliya is at the Ministry of Agriculture?! What’s 10% of USD30 mile as a cut? Mulalaba bwangu ayi?

  11. The only benefit you will have from diverting water from Kafu to Kariba is from the volume which the Kafu Gorge power plant is not able to handle and spills over the dam. And increasing capacity at the Kafu Gorge will certainly be much cheaper than to transfer the water from Kafu to the Lake Kariba. Hydro electic power is about investing as little as possible to harness as much as possible of the potential energy.

  12. Great article. If only we had the political will to turn around energy provision in the country. Seems there is a politician pulling the wrong strings!!

  13. VERY GOOD ARTICLE and VERY GOOD POINTS OF VIEW! A VERY RICH DISCUSSION INDEED. We can see that there are pros and cons to this idea. What about joining this proposal to the OLD or EARLIER IDEA OF TAPPING SOME WATER FROM THE LUAPULA RIVER TO FLOW INTO THE KAFUE EITHER to boost the Kafue river volumes to support ONWARD CHANNELLING to the Zambezi fior KARIBA OR just to use the water to INCREASE POWER GENERATION AT ITEZH -TEZHI and KAFUE GORGE? So far the cost of tapping Luapula water into Kafue are said to be quite low except that political issues with the DRC may complicate the idea. However, if that could be the case, we could even look at tapping water from the CHAMBESHI before it enters Bangweulu and cascade down to Kafue!

  14. If I was the one with this kind of fantastic ideas, I surely would have put these ideas in presentation format, seek an appointment with the powers that be, including President ECL and presented this fantastic alternative solution to the power woes that we are currently faced with. Bringing this idea to LT will not go anywhere at all. I implore the writer to spend time and work on a presentation, if you need help I can assist at no charge at all.

    • Ba General, I would like to take you up on your offer.

      Please get in touch with Lusaka Times and they will provide you with my contact details.

  15. We can also divert the floods from Lusaka to replenish the water in the Kafue River. The problem is that our ministers responsible for this are not thinking.

  16. Adrian is worried about the impact on Kafue lower power station of diverting water to kariba. He seems not to know that kafue existing power station and kafue lower are essentially one and the same, the lower is barely three km dowmstream of upper. So diverting water has proposed affects the whole scheme. And what about the irrigation schemes upstream, sugar etc? Appreciate the idea but please think more deeply or let other experts assess the idea. I am amazed at how some people think that sich ideas have not been considered before. Especially when UPNDonkeys comment and bring in an innocent President Lungu!

  17. You build a canel at great cost only to find the Kariba due to its age can not handle the extra volumes. Only saying.

  18. @Terrible u were sounding intelligent until your last paragraph. Why does everything have to be political….why dont we all work for a better Zambia

  19. The apparent underlying suggestion in this article is that the current serious energy shortfalls are as a result of a lack of adequate water. The current abysmal load shedding stems more from other reasons. Even when the Kariba has had enough water, the load shedding has not reduced significantly. The writers proposals are welcome but have more to do with sustainability – for future generations. The last six years or so have been fraught with mismanagement, self aggrandisement, political appointees, lack of know how in the current crop of engineers and hence poor everyday maintenance etc. Even in the years that we did not have this rate of load shedding, Zesco only supplied a fifth of the country with electricity. Nothing to do with demand – just inefficiency and politicisation of what…

  20. Good idea floated. Let’s debate it. Let’s divert 70% of Kafue river and leave the 30% on it’s original path. It could be costly but it is do able. Let’s not shut out the idea, let’s look for the money and carry out the project

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