Lusaka-President Edgar Lungu this week toured the Kariba dam which borders Zambia and Zimbabwe in order to get a deeper appreciation of the water and power generation situation in Zambia.
While touring the Kariba dam site last week, Lungu learnt from Zambezi River Authority (ZRA) that despite favourable inflows into the catchments, more time, probably until mid 2020 is needed to allow water to reach the Kariba storage space.
ZRA Chief Executive Officer, Munyaradzi Munodawafa, indicated that the high water volumes seen at the Victoria Falls are a positive development. He however noted that even with this inflow the dam might not reach the specified heights and curtail power outages. Munodawafa also noted that these high volumes at Victoria Falls might take nine weeks to reach Kariba dam.
Kariba dam, whose maximum generating capacity is close to 1,080 MW now generates an average 275 MW owing to insufficient water as a consequence of the drought. Water intake at Kariba is arguably expected to increase by mid year, though hydrologists argue that this might be insufficient to meet the required water levels at the dam.
It seems the flash floods and high rainfall patterns recorded in the southern African region in the past season have not benefited the Kariba hydro-electric dame-the main water and power source for Zambia and Zimbabwe. The dam has been unable to fill up to its capacity and has seen the power outages continuing.
Specifications for the 60-year old dam indicate that the structure is over 223 kilometres long and up to 40 kilometres in width, covering an area of close to 5,580 square kilometres with storage capacity at 85 cubic kilometres. The mean depth of the lake is estimated at 29 metres with the maximum depth at 97 metres, a feat that can only be attained by a generous out pour of reliable rainfall.
Experts told The Southern Times that the dam needs to raise water levels to an average height of 478.83 metres above sea level compared to last year’s level of 480.45 metres.
Recent arguments by end-users and Zambia’s Government indicate that the continued load management by the power utility-Zesco and its Zimbabwean counterpart, ZESA, is unstable. Management at the two companies-ZESCO-ZESA and their regulator Zambezi River Authority (ZRA), are often blamed as not having done enough to reduce the effects of the power shortages that frustrate economic growth. They are often blamed as not having done enough to reduce the effects of the power shortages that frustrate economic growth but ZRA defends its position. It argues that despite the increased water levels from its catchments including Chavuma in northwestern Zambia, inflows to Kariba dam cannot be expected to fill up the reservoir.
Instead, it would take nine weeks for these inflows to reach the dam, said Munodawafa. Water collected at the Chavuma catchment instead, was used to fill the Leaui plain in western Zambia and until the river banks burst, will the water flow out into Lake Kariba.
ZRA has this year cautiously restricted water usage to 22 billion cubic meters of water for the two countries and Munodawafa has said the situation arose to allow for the preservation of water for next year and not increase utilization for the two utilities-Zesco and Zesa to avert a crisis. He also emphasized that even when the water reaches the Kariba Dam it will not be sufficient to generate the required electricity.
At the site tour, Lungu reiterated the government’s commitment to invest in other sources of energy other than hydro-electricity to address the power challenges.
Zesco Managing Director, Victor Mundende, indicated that it is management’s desire to sustain load management at between 10-12 hours until the year-end as the allocation was insufficient and if forced to operate equipment at full throttle that would spell doom for the project.
Mundende indicated that, “Just to give a comparison, last year, we received 17 billion cubic meters of water and this year we have been given 11 billion cubic meters, so you can see that this year we have less. It is owing to such that you will observe that from an installed capacity of 1,080MW, we are only able to generate 275MW in order to save equipment and avoid depleting the water“
He added that, “You can see our units and our machines are all available, we actually run and reach this capacity but we can’t because the water is not enough so we only have 275MW.” We have a total generation now sitting at 1,072MW and a peak demand of 2,200MW hence our shortfall is 810MW at peak so we have to find ways and means of living with this, for now at least, even as we put in measures to mitigate this deficit.”
He said it was unlikely to fill Kariba Dam in one rainy season and that would take three seasons of good rainfall to fill the Kariba because of the structure specifications.
“Kariba dam is a multi-year reservoir; you cannot fill the dam in one single season, it takes three years of good rainfall to fill it up to the maximum, similarly, it means on the reverse side, when it is full, you can use the water from that reservoir for the next three years even when you have a drought as long as you are not using it at full generation but at minimum generation.” argues Mundende.
The current rainfall intake this year saw the dam absorb a low seven per cent forcing the utility to seek to raise the reservoir storage.
It, however, did not guarantee increased generation this year despite the good rains as it can only rise by a third of the required maximum.
Lungu later toured the Kafue gorge lower which is under construction and is expected to start generation of power by the end of this year and he indicated that his government is investing in other energy sources in order to meet the countries growing demand.