Kariba anchors power supply despite lack of water

the herald

business journalist

Kariba South Power Station remains Zimbabwe’s main source of electricity despite generation limitations due to low water levels, which prompted the Zimbabwe River Authority (ZRA) to ration the amount of water used to generate electricity from Lake Kariba.

The ZRA, being a bi-national organization jointly and equally owned by the governments of Zimbabwe and Zambia, which generates electricity from the northern shore of Lake Kariba, is mandated to manage the Kariba Dam and develop additional water storage infrastructure along the shared part of the river located between the two states.

The lake, the largest man-made body of water in the world, sits on the mighty Zambezi River, a giant water system that begins in northern Angola but has seen reduced flows in the Kariba Dam in the recent years due to the negative impact of droughts. and the late onset of rains in the river catchment, particularly the Barotse plains in western Zambia.

The lake level has steadily declined due to low inflows from the Zambezi River, ending the review period at 479.64 m (29.20% usable storage) on August 2, 2022, from 482.21 m (48.55% usable storage). storage) recorded on the same date last year,” ZRA said in its latest update.

Because the Zambezi River drainage basin originates from and largely depends on the flow of the Barotse Plains in western Zambia, and since the Barotse Plains lie within the Zambezi River drainage basin, they must first be flooded at the height of the rainy season in February before releasing the excess water into the river, which only experiences a peak flow in Lake Kariba in April and June.

This means that Zimbabwe and Zambia cannot expect significant changes in Lake Kariba power generation soon after the onset of summer rains until significant amounts of flow have entered the reservoir. around the middle of next year, also assuming an early onset of the rains. This year.

Currently, the 1,050 MW power station is producing electricity at a significantly reduced level, in line with the water ration permitted by the ZRA, to avoid excessive water use which could lead to lake depletion and require a long period of time to fill up in order to be usable again for electricity generation.

Zimbabwe is therefore banking heavily on the scheduled completion of Hwange Power Station Units 7 and 8, with the first generator due to come on stream around October this year and the second in the first quarter of next year, in a development that will boost electricity supply. by an additional 600 MW.

HPS, a 920 MW thermal power plant, is currently capable of generating an average of 450 MW due to the old power plant equipment built in the mid-1980s and past its economic life. The advanced age of the power plant affects its reliability and sees it frequently failing while the electric utility faces currency exchange problems to procure spare parts on time.

Zimbabwe Power Company (ZPC) said in a recent update that power generation for the second quarter to June 30, 2022 exceeded the target by 0.35%, with Kariba Power Station contributing the bulk to 72% of total production.

ZPC, in its quarterly power update, said it sent out 2300.31 GWh, slightly exceeding the quarterly target of 2292.31 GWh, however, this was significantly below the electricity required by the country for use. industrial, commercial and domestic, prompting the electric utility to load shedding to balance supply and demand.

“Kariba power plant contributed 72% of the total power generation during the review period, Hwange power plant contributed 27% while small thermal power plants contributed only 1% to the total energy production in the quarter,” he said.

ZPC noted that all eight Kariba units were available for peak on-demand power generation during the quarter. under review and due to increased production, the station exceeded its quarterly target by 14.17%.

The power company said production in the quarter was 6.39% higher than production in the second quarter of 2021.

“This is attributed to the increase in water allocation from 15 billion cubic meters in 2021 to 22.3 billion cubic meters in 2022.”

According to the update, from January to date, ZPC has issued 4469.08 GWh thus exceeding the target for the period set at 4177.60 GWh by 6.98%.

ZPC said this represents 49% of the annual target set at 9,111 GWh.

During the reporting period, ZPC was allocated 22.5 billion m3 by the Zambezi River Authority “ZRA” for power generation, which translates to 5,312 GWh and an average capacity of 606 MW.

ZPC said the lake level rose from 478.81m at the start of the quarter to a high of 480.21 on June 14 and then dropped to 479.64m at the start of August 2022.

“This represents a lake level rise of 1.34m during the quarter. By the end of the second quarter of 2022, the station had consumed 13.59 billion m3 against a revised target of 13.00 billion m3.

ZPC noted that in order to alleviate coal supply issues facing thermal power plants, the cabinet has approved a long-term coal supply agreement that will allow coal suppliers to obtain bank financing at long term that they need to develop their production. Regarding the project status, ZPC said the Hwange expansion project was at 84.82% at the start of the quarter under review and ended the quarter at 89.95%.

“Although the project schedule has been impacted by the Covid-19 pandemic, recovery efforts are now underway to complete the project as soon as possible,” ZPC said.

He noted that the ZPC Resettlement Action Program (RAP) is progressing well with the overall progress of all construction sites at 90% with most houses at roof level.

“Two (2) of nine (9) construction sites (Epping Forest and Sawmills) have been completed to date.”

During the quarter under review, ZPC said it had started receiving various components for the Deka project, which is financed by a $48.1 million Line of Credit (LOC) granted by the Government of India to the Government of Zimbabwe.

“The first batch of 3,555 mild steel tubes was received on July 10, 2022. The unloading and transportation process will take approximately one month, as the tubes are transported in batches of 30 trucks.

“Work on water control is at 55%.”

ZPC said the goal is to eliminate water loss and recover approx. 750 m3/h by mainly treating the ash treatment plants, the hydrant system and the leaking valves in the station.

Alan A. Seibert