Kariba Dam water levels fall
PHILLIMON MHLANGA
Water levels in Kariba Dam, the world’s largest man-made reservoir, have fallen to 481.59m this week on Tuesday, which is 6.09m above the minimum operating level of 475.50m, threatening the electricity supply to Zimbabwe, it has been learnt.
Business Times can report that in June this year, the water levels at the Kariba Dam stood at 482.82m.
But, it dropped to 481.86m this week, reflecting a 45% of capacity.
On the same day last year, the dam levels stood at 480.8m, reflecting 37.81% usable water storage.
Kariba Dam is designed to operate between 475.50m and 488.50m, in order to generate electricity.
It is understood that each machine, when running, requires a massive 150 cubic metres per second of water, which translates to a stunning 1 200 cubic metres of water per second when all the units at Kariba South Hydroelectric Power Station, are running.
Zambezi River Authority acting CEO Edward Kabwe attributed the drop over the past three months to the coming of the dry season.
“The lake level recession currently being experienced is largely attributable to the close of the 2020/21 rainfall season and this trend is expected to continue throughout the remainder of the 2021 dry season up until the start of the 2021/22 rainfall season,” Kabwe said.
Kabwe said the Authority would continue to observe the hydrological situation of the Kariba catchment and manage the Kariba reservoir to ensure continued availability of water for power generation.
The trend, which is expected to continue throughout the remainder of the year, is very troubling because if water in the Kariba Dam depletes to below the stipulated minimum threshold of 475.50m, Kariba may only be used for recreation and fishing purposes as low water cause mechanical problems as it cannot turn turbines to generate electricity.
Kariba Dam, which is the main source of power for Zimbabwe and Zambia, contributes more than 60% of electricity consumed in the two neighbouring southern Africa nations.
Kariba South Hydro Power Station has remained Zimbabwe’s biggest generator of electricity and produces relatively cheaper and reliable electricity for the country but is now unlikely to perform to its optimal due to reduced usage of water.
It has been supplying electricity at an average cost of US$0,02 per kilowatt hour (kW/h) while the four thermal power plants at Hwange, Harare, Munyati and Bulawayo have been generating power at an average cost of between US$0,08 per kW/hand US$0,16 per kW/h.
The high costs are due to inefficiencies at these thermal power stations, associated with ageing equipment, a situation which makes domestic production of electricity relatively expensive compared to regional counterparts.
Kariba South Hydropower Station has an installed generating capacity of 1 050 megawatts (MW), after the power utility in 2018, commissioned an additional 300MW, its biggest investment in electricity in more than 25 years.
But, it generates about 1 000MW daily.
Zimbabwe is currently experiencing power shortages, which is ravaging the already ailing economy and the government is seeking investment and sustainable solutions to the power challenges bedevilling the economy.
Zimbabwe requires about 2 200 MW daily at peak hours but was this week generating about 1 200MW.
As of Tuesday this week ZPC, which is a power generating unit of ZESA Holdings, and operates power stations in Kariba, Hwange, Bulawayo, Munyati and Harare, produced 1 238MW.
Kariba South Hydropower Station supplied 894MW from a possible 1 050MW, Hwange, the country’s largest coal-fired plant produced 320MW, Harare (14) and Munyati (10).
