ZIMBABWE faces a precarious power supply situation following indications by authorities that water levels in Lake Kariba, which houses the country’s largest power station, Kariba South, have fallen to a near-record low since completion of the lake in 1959.
Due to limited domestic generation capacity caused by the low lake water levels and aged generation equipment, the Southern African nation is forced to implement long periods of load shedding across the country.
Local industry reportedly needs at least 18 hours of uninterrupted power supply per day in order to operate at optimum levels, according to the Confederation of Zimbabwe Industries (CZI), Zimbabwe’s largest industrial lobby.
CZI’s past president, Joseph Kanyekanye, told the lobby group’s annual congress in August this year that erratic power supplies had forced the industry to drastically reduce production levels, which could negatively impact the country’s economic growth targets.
Exporting companies, mostly miners, have since obtained Government approval to pay in foreign currency in efforts to ensure a more reliable power supply scenario, yet the national power utility says that even then, supply cannot be guaranteed.
Other economic agents, buckling under the negative impact of frequent load shedding and high-cost alternatives like diesel generators, have since invested in solar systems.
Zimbabwe’s economy is projected to grow by 4,6 percent, revised down from 5,5 previously forecast by Finance Minister Mthuli Ncube in the 2022 national budget, because of a number of factors including high inflation and Government spending cuts to contain inflation.
This also comes as CZI has warned of punitive interest rates, after the central bank raised the bank policy rate, which determines minimum interest rates charged by banks on loans, to a record 200 percent from 80 percent, which could throttle many businesses.
The Zambezi River Authority (ZRA), a statutory body that administers the affairs of the riparian Zambezi River, said the lake’s live water level had plunged to 9,32 percent as of November 1, 2022 from 31,59 at the same time last year.
This could spell serious power supply issues given Kariba Dam, on which the 1050 megawatts Kariba South hydropower sits plant, is Zimbabwe’s largest power station after Hwange, which in its prime generated 920MW, but can now only afford an average of 450MW due to the aged plant.
The installation of two new generators at Hwange by Chinese contractor, Sinohydro, could add 600MW to the national grid, but 50 percent will only become available at the end of the first quarter of 2023, assuming no unforeseen hiccups.
Lake levels are expected to start rising in the first quarter of 2023, providing flows at Chavuma gauging station, upstream of Victoria Falls, improve conditional on good rainfall in the river’s main source of water in western Zambia.
“As per hydrological trends in the last quarter of every year, the lake is in recession pending the onset of the next rainfall season, in this case, the 2021/2022 rainfall season came to a close in mid-year 2022 and saw reduced river flows.
“The recorded lake level on 1st November 22 was 476,85 metres with 6,04 billion cubic metres usable live water or 9,32 percent. This recorded level of 476,85m places the lake 1,35 metres above the minimum operating level of 475,50m.
On the same date in 2021, ZRA said, the lake level was higher at 479,97m with 20,47 billion cubic metres or 31,59 usable live water storage, with the water being 4,47m above the minimum operating level,” ZRA said.
Power generation at Lake Kariba works within a water level range spanning about 10 metres, the minimum and maximum height of water used to drive generator turbines.
Below the minimum operating level, the risk is that the lake may be depleted, which may need several years of uninterrupted inflow to fill up again.
On the positive side, the 26th Southern Africa Climate Outlook Forum, which took place in August this year, predicted using meteorological data, normal to above normal rainfall in Zimbabwe and Zambia as well as the Zambezi River catchment areas.
ZRA undertook hydrological simulations of the hydrological using the normal to above normal rainfall during the 2022/23 rainfall season and allocated 40 billion cubic metres for power generation, shared equally between Zimbabwe and Zambia.
But it is short to the medium-term supply of power for Zimbabwe that observers believe presents fears of a worse power supply situation for a country already blighted by rolling blackouts, especially due to the situation at Lake Kariba.
Lake Kariba only starts to rise towards the end of February while inflows peak around April, when the water flow on the Zambezi River increases after the Barotse plains, an expansive floodplain and the river’s main catchment in Western Zambia, have saturated and started releasing water into the river.
Zesa said recently that relying on Kariba (at least immediately and over the next few months) for security of power supply in Zimbabwe at the moment was not advisable, as it was largely dependable on the outturn of the 2022/23 rainfall season.
“Water rationing has since been instituted and peak flow into the lake is only after the month of March,” Zesa said in a written response to Business Weekly recently.
“Notably, the Lake has fallen from about 18 percent usable live water in September 2022 to 9,32 percent by November 1, 2022.
While Zesa tries to ameliorate the power situation through imports from Mozambique, Zambia and South Africa, the State power utility cannot import enough to cover the deficit from domestic generation due to limited access to foreign currency.
Zesa said peak demand for power this year was 2 000MW yet the country could only produce about 1 400MW at the best, assuming the absence of breakdowns at Hwange thermal plant, which are frequent though, and Kariba running at full throttle.
A former senior executive and engineer who worked at Zesa, said the current situation at Lake Kariba was a “disaster”, urging the State power utility should stop further power generation to avoid depleting the dam, as this could damage the shared river’s ecology.
“It’s a disaster, they have to curtail generation now,” the former ZESA senior executive said. “The effect of all this is that, since we share the water with the rest of the ecosystem, if the water allowed for power generation is used up, they cannot continue to generate because they may damage the rest of the ecology.”
“And when they curtail generation, it will only make the (power supply) situation worse considering that they are already load shedding due to limited generation capacity. But they are hoping Hwange 7 and 8 will alleviate the situation somehow.
“We are getting 300MW now then 300MW later, so it will alleviate the situation; (but) it will not compensate for Kariba, but it will alleviate the situation,” the source said on condition they are not named.
Asked what the hydrological pattern of the Zambezi River, as it relates to Kariba Dam, spelt for Zimbabwe’s power supply, the former Zesa senior executive said the situation may only start to improve after the first quarter of next year.
“We get our maximum flow around April/May (annually) and most of the catchment (of Zambezi River) is not in Zim . . . it’s north of Zambia and the area around Zaire (DRC),
that is where most of the water come from; that is the biggest catchment area,” the source added.
The government has embarked on several initiatives to make Zimbabwe self-dependent on energy, including expanding Hwange by 600MW and rehabilitating the old generators under a multi-million-dollar project to restore nameplate capacity.
Zimbabwe is also working with Zambia to build a massive hydropower plant upstream of Kariba at Batoka Gorge, but this may not come online for at least the next three to five years given the size of the investment and other logistics.
Harare has also issued several licences to independent power producers in the hope of ensuring the security of supply and making Zimbabwe a net export of electricity, but while a few have materialised, the bulk are yet to take off the ground.
Livestock and Meat Advisory Council (LMAC) chief executive Dr Reneth Mano said companies are obligated to preserve the value of their local currency earnings against rising inflation and negative real interest rates on Zimbabwe dollar bank deposits.
“Some may choose to buy bricks while others might choose to buy ZSE shares of performing counters.
“Above all options, the easiest thing to do is to convert ZWL into USD cash holdings so that one can meet monthly wage bill and Zesa bills all of which are now quoted in USD and payable in USD and/or ZWL.”
“The Ministry of Finance approved USD Zesa billing to companies and USD under the multicurrency regime. What the Ministry should do therefore is to facilitate sale of USD by banks to Government contractors. Not just gold coins,” Mano said.