Zambia and Zimbabwe are looking to diversify their energy mix as climate change linked droughts and heat make hydropower less reliable.
Zambia is facing 21-hour power cuts from 14 September when its hydropower plant on Lake Kariba is set to be turned off due to insufficient water.
Following severe droughts and increased evaporation amid scorching heat, the lake's live storage - i.e. the water available for power generation - dropped to just 1.1m on 9 September, according to the Zambezi River Authority (ZRA). This represents 7.7% of its usable storage. On the same date last year, this stood at 25%.
The Kariba Dam, which created the world's largest man-made lake by volume, straddles Zambia (to its north) and Zimbabwe (to its south). Each country has its own power station on its side the dam with a capacity of a little over 1,000MW. The dam is a primary source of electricity in both countries. Currently, however, Zambia's plant is generating 98W and Zimbabwe's 214MW.
When Zambia's station shuts down having exhausted its allocation of shared water, it will be the second time generation has stopped since the dam was completed in 1959. The first occasion was in November 2022 when power generation was stopped on the Zimbabwean side. The lake's lowest recorded live storage was reached in December 2022 when it stood just 10cm above its minimum operating level, representing 0.8% of usable storage.
The recent low water levels in Lake Kariba have been attributed to severe droughts, linked to the El Nino weather patterns, and extreme weather made more likely by climate change. The Zimbabwe Meteorological Services says that, over the past century, daily minimum temperatures have risen by 2.6°C and daily maximum temperatures have risen by 2°C. Over this same period, rainfall has decreased by 20% and the frequency of droughts have gone from being a once in a decade phenomenon to occurring once every three years.
Desmond Manatsa, a professor at the Bindura University of Science Education (BUSE) and president of the African Alliance for Disaster Risk Institutes, says that cycles of precipitation have shifted and shortened too due to climate change. "Onsets [of rain] are delayed while cessation dates also come early, leading to the shrinking of the rainfall season in most areas," he says. "Rainfall is now mostly starting in mid-November rather than mid-October."
The effect of this for Zambia and Zimbabwe is that their energy surpluses, on paper, have become large energy deficits.
Zambia's installed power generation capacity of 3,457MW exceeds its peak demand of 2,300MW, but with 83% of this power coming from hydro, the country has been plunged into a shortfall of nearly 1,300 MW. Zambia's Kafue Gorge, Lower Kafue Gorge, and Itezhi-Tezhi Power Company hydropower plants are also operating at fraction of capacity.
"While the imports [of electricity] are critical, they may not be sufficient to fully balance supply and demand," explained Matongo Maumbi, spokesperson for Zambia's state-owned energy company ZESCO, warning of impending 21-hour power cuts from September. "Emergency power rationing remains a possibility, and ZESCO is exploring all available options to stabilise the situation."
In Zimbabwe, the situation is similarly acute. The country's installed power generating capacity of 2,700 MW is enough to meet peak electricity demand of 2,200 MW. However, after losing over 800 MW at its Kariba hydro plant and with its aged coal-powered plant at Hwange frequently breaking down, Zimbabwe's supply averages 1,200MW. This has resulted in citizens going for up to 18 hours without power.
Zimbabwe's Energy and Power Development Minister, Edgar Moyo, has warned that matters in Kariba may get even worse early next year. "We will still maintain our generation capacity (of 214MW) up to the end of the year," he said. "However, we will continue to monitor our water levels and our production capacity."
Diversifying the energy mix
Despite growing challenges, hydropower looks set to remain central to electricity generation in Zambia and Zimbabwe. The source of power continues to have numerous benefits.
"Hydropower has the advantage of providing clean power and yet also providing the base load and ancillary services required by power systems, which intermittent renewable energy sources such as wind and solar cannot provide," says Stephen Dihwa, executive director of the Southern African Power Pool Coordination Centre (SAPPCC), which coordinates power systems in the region. "As such, [hydropower] will play a critical role even in future power supply."
Dihwa says that measures can be taken to reduce the impact of droughts on hydropower, including through improved forecasting and management of the rate at which water is used. He adds that studies are ongoing to explore other strategies.
"Some of the solutions are hinged on regional integration and conjunctive operation of plants on the same water courses," he says. "Other solutions take cognisance of the fact that it's not all the river basins that are affected by droughts in the region or they could be affected during different seasons. For example, the Congo basin in the DRC is not affected much and ways in which this could assist plants on other basins could be pursued."
Zambia and Zimbabwe are even looking to expand their hydropower capacity through the new $5 billion Batoka Gorge Hydro project. This development is planned upstream of Lake Kariba and could generate 2,400MW.
"Batoka will serve as a mitigation measure to some of the hydrological problems at Kariba, while at the same time directly contributing a significant increase to the desperately needed power supply capacity of Zambia and Zimbabwe," says ZRA chief executive officer Munyaradzi Munodawafa.
At the same time, the two countries are looking to diversify their energy mixes.
Zambia has signed a string of deals for solar plants, including a $2 billion deal with the UAE's state-owned company Masdar for a 2,000MW solar project in January last year. ZESCO also entered into a power purchase agreement (PPA) with the Canadian firm SkyPower Global earlier this year to supply 1,000MW of solar energy to 4 million households.
Zimbabwe has similarly signed numerous power generation deals that would ramp up its solar capacity. These include an agreement with a Chinese firm for the development of a 1,000MW floating solar plant on Lake Kariba, a 500MW plant in Victoria Falls, and arrangements with 27 small independent power producers to develop around 1,000MW of solar capacity.
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Nyasha Frank Mpahlo, the director of Green Governance Zimbabwe Trust, says green energy is becoming more affordable, though it will take time before most African countries can enjoy this cheaper energy. "We still have to import lithium batteries, solar panels, and other technological aspects of the energy transition, that's a key challenge," he says.
This is partly why both countries are also turning to coal, despite its heavy carbon emissions. In July, Zambia announced plans for the construction of a $400 million coal power plant that would double the country's power from coal to 600MW. Meanwhile, Zimbabwe is currently upgrading its 920MW coal plant at Hwange to 1,520 MW and has plans for two new coal power stations that would add an additional 2,800MW and 2,100MW of coal power respectively. They are looking for new funding after China withdrew its support for overseas coal in 2022.
Johnstone Chikwanda, a Zambian energy expert, says the turn to coal should be understandable to climate diplomats from other countries given many African countries challenges and meagre contribution to carbon emissions historically. "We expect to continue diversifying the electricity generation sources in order to enhance security of supply," he says.
Cyril Zenda is a Zimbabwean freelance journalist and writer based in Harare.
