The Sunday Mail
Debra Matabvu
THE Zimbabwe Power Company (ZPC) — a subsidiary of the Zimbabwe Electricity Supply Authority (Zesa) — last week reconnected Hwange Thermal Power Station’s Unit 6, adding about 150 megawatts (MW) to the national grid, while another 100MW unit is expected to be brought back online within the next two weeks.
Both units were undergoing routine maintenance, and their return to service is expected to bring national power generation capacity close to 1 500 MW, substantially reducing the current power shortfall, especially at a time when low water levels are affecting output at the Kariba Power Station.
As part of measures to pre-empt potential power shortages, the Government has approved the introduction of the utility-scale battery storage system (USBSS), also known as the large-scale or grid-scale battery storage.
It acts as a giant rechargeable battery designed to store excess electricity generated by power plants and release it back into the grid when needed.
The system will store excess power generated during off-peak hours and release it back into the grid during peak demand periods.
Installation of the USBSS, which is expected to be operational by September 2024, is envisaged to improve overall grid stability and mitigate the effects of low generation at Kariba.
In an interview with The Sunday Mail, Energy and Power Development Minister Edgar Moyo said the reconnection of the two units at Hwange was set to enhance daily power generation to around 1 500MW.
“Currently, we are producing about 1 300MW against a demand of between 1 700MW and 2 000MW,” he said.
“Today (Thursday last week), we are bringing back another unit, which was down, Unit 6, one of our biggest units, which will give us 150MW.
“On April 7, we are bringing back another 100MW unit, assuming that nothing happens. We would have raised our production to 1 500MW.”
Local power generation, he said, was also being augmented by independent power producers that are generating an average of 80MW daily.
“I think this will bring the shortfall to just 200MW.
“This difference will be covered through load shedding and imports.
“However, we want to keep our imports as low as possible.”
Minister Moyo said plans were underway to instal the first USBSS at a selected location by September 2024.
Zimbabwe is understood to have lost about 50 percent of its generation capacity as a result of low water levels in Lake Kariba.
“To rectify the situation, we are working towards introducing the utility-scale battery storage system,” he added.
“Utility-scale battery storage allows us to store some of the energy during off-peak periods.
“Our demand is different for peak and off-peak periods.
“So, during the off-peak period, we have that capacity which is surplus, which can be generated and stored.
“That stored energy can then be used during peak demand periods.”
The USBSS stores surplus electrical energy during periods of low demand, typically at night.
They then discharge the stored energy back into the power grid during peak demand times, usually during the day.
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The system helps balance fluctuations in electricity supply and demand. It thus ensures consistent and reliable power supply.
The USBSS primarily uses lithium-ion battery technology due to its efficiency, scalability and relatively fast charging and discharging capabilities.
Added Minister Moyo: “Our target is to have this system by September, and we are still discussing it.
“If everything works according to plan, we should have this by September.
“They will not all come at once, but we will build on what we would have procured.
“They will be deployed in different parts of the country.
“Possible locations include installing them at thermal power stations, where operations have stopped as one of the ways to recapacitate them.”
Refurbishments
Minister Moyo also said the Government had secured a portion of the US$310 million loan from the Export-Import Bank of India to finance the refurbishment of six old units at Hwange.
“On the repowering project, part of the funding was secured from the Export-Import Bank of India, and what is now left is the drawdown approvals,” Minister Moyo explained.
“We require additional funding as the current allocation is insufficient for the entire process.
“However, refurbishment has already begun on Unit 5.
“The plan is to bring Unit 5 back online in 2025.”
As of last Friday, ZPC was producing 1 027 MW — Hwange (774MW), Kariba (250MW) and independent power producers (3MW).
Climate change and challenges with power generation infrastructure have resulted in electricity shortages in the region.
On March 11, Zambia introduced eight-hour daily load shedding.
South Africa is similarly affected.
