Just after the Second World War, political leaders in what was Southern Rhodesia started to think about how they would meet the needs of the country for electrical energy. After that, the debate raged between Northern and Southern Rhodesia as to the merits of building the Kariba Dam. Eventually, it was the Federal Government who made the decision and the contract was awarded to an Italian company funded by a loan from the World Bank.
It was a huge step of faith for a small emerging economic system that was recovering from the global turmoil of the War. The dam would be one of the largest on earth and would be one of the biggest civil engineering contracts ever undertaken. It was the largest loan granted by the World Bank in Africa. The dam was commissioned in 1960. Prior to this development the country had relied on three small coal-fired power stations built and located in the main Cities and outside Kwekwe to accommodate the development of Zisco Steel.
The next major development came in the late sixties when the Government developed the Hwange Power Station. Further developments were made impossible by the conflict of the Liberation War and Zimbabwe came to Independence totally dependent on three old steam driven power stations, Kariba Dam with its 700 megawatts and Hwange – strange combination of differing components smuggled into the country in defiance of UN Sanctions. A problem which has bedevilled the plant until today resulting in the Power Station never reaching its potential.
Why electrical energy was not a priority for the new Governments is a mystery but the reality is that no new generation capacity was built until the Chinese constructed the new generation hall at Kariba and installed another 600 megawatts. This followed a similar development on the north bank where Zambia did the same thing.
We now face what was an almost inevitable crisis as water levels in Kariba reach new lows and no new power sources are available locally or even in the region.
The question we must ask is why has Kariba reached this point? The answer is very simple, poor management of the whole river system. 100 years of records on the Zambezi River made the point that over time, the sustainable yield of the river in terms of power generation at the Kariba Wall was 1200 megawatts. The design team installed 1 400 megawatts. They knew this was about right and in the next 60 years the dam spilled only 4 times, all normal riven flow going through the wall and its giant turbines.
Once thought to be a costly mistake, Kariba produces the cheapest electricity in the world and the loans that built the wall and its turbines are long settled. This made the power station an attractive alternative to other projects which would be more expensive, both in capital and operating costs. So it was a natural to increase its capacity and hope that the river could support the new capacity.
Zambia took the plunge first and under the very noses of the Zambezi River Authority (ZRA) and the Zimbabwean Energy Ministry, began to use much more water than they were actually allowed. When our people woke up to the issue, the dam had dropped to 16 per cent of its capacity. The ZRA woke up to the issue and restrictions were slapped on Zambia and the dam recovered slowly. By then the Zimbabwe Government was already committed to the South Bank extension and this was contracted and completed last year, raising the generation capacity of the Dam to well above its sustainable level. As a result, water levels below the dam rose by two metres.
Water restrictions have now reduced power generation to a third of the capacity of the Dam and even at this level, the dam might well have to be almost switched off before the next rains. The knock on effect of this is to take cheap, clean hydroelectric power out of the sales mix of the power utilities in the region making power supplies more expensive.
I am mystified by these events because all through the past season I have been watching the ITCZ as it sat over Zambia and over the majority of the catchment of the Zambezi above the Falls. I have not seen the rainfall figures for the area but some years ago I went fishing on the Chobe and the on the flood plains in the Caprivi Strip. We fished for a day and travelled some 70 kilometers in the reed beds. The Chobe has no water of its own and all the water in the river comes from the upper Zambezi when it floods over its banks.
We had a great day of fishing but I asked the guide why no wildlife, no hippos and no crocodiles. Just swathes of reeds 3 metres high and water pulsing through narrow channels to the Chobe. He said to me that anything that crossed the Chobe from Botswana was shot in days. It occurred to me that if the hippo were not to return – no one would clear the drainage channels. If that happened the vast quantities of flood water would be dammed up by the reed beds, drainage channels blocked and the water stagnant.
I thought about the massive flood plains in northern Zambia and asked what the hippo populations were like – no one could tell but I said to anyone who would listen that if what was happening in the Caprivi S trip was happening in the north then the consequences for the lower Zambezi would be critical. One person who was familiar with the situation in Malawi said that there the same thing had happened to the Hippo population on the Shire river which drains Lake Malawi and the Government had to import Hippo to restock the river to drop the level of the Lake.
But the most immediate question is how do we manage our system until we can get more capacity built? If we cannot find a solution to this question, then there can be no talk of growth and recovery – the energy just will not be available to even maintain what we are currently doing.
My suggestion to resolve this problem is as follows:
Start with putting Kariba Dam on generating power only during daylight hours. This would help us meet peak demand. The ZRA should be instructed to investigate the situation in the Zambezi Flood Plains and take appropriate action.
Secondly, I suggest we introduce a subsidy of 50 per cent on the cost of all new solar instillations. Solar can easily meet our needs for a quarter of our power needs during the day – do not provide for storage – just panels and use the sun. All solar instillations should be encouraged to install excess capacity and smart metres introduced to provide for sale of any surplus to the national grid. Finance should also be provided over three years at a reasonable interest rate.
Thirdly, we need to get Hwange working to capacity on a continuous basis so that this can provide us with our base load demand and run during the night. The installation of the two new generators at Hwange should be expedited.
Fourthly, we need to start the construction of the private sector sponsored power station at Lususlu on the banks of the Kariba Dam.
Fifthly, we need to investigate urgently how we can use natural gas for power generation and build a plant at Mutare for this purpose, this is clean energy and can be installed quickly. This should be a private sector project. Natural gas is going to be the cheapest form of energy in the long term.
The Central African Power Pool is located in Harare and immediate talks should be initiated to secure an allocation of electrical energy from the region to prevent a real crisis in Zimbabwe. Clearly we will have to pay more for power and this should not be ignored. We should not imagine that we can hold energy costs down in defiance of our current economic fundamentals.