ELECTRICITY supplies to households and industries will plunge by 400 megawatts (MW) after the Zambezi River Authority (ZRA) reduced water allocation for power generation at the Kariba Dam by nearly 30 percent, the Financial Gazette can exclusively reveal.
While the reduction in water allocation is meant to ensure that there is enough resource to sustain power generation until the onset of the 2015/2016 rainfall season, it would worsen the power supply situation in the country at a time Zimbabwe is battling machine breakdown at Hwange Thermal Power Station.
Hwange Thermal Power Station, the biggest plant in Zimbabwe, was producing 300MW, according to Tuesday’s figures, against installed capacity of 920MW.
The Bulawayo Power Station, which could have mitigated the crisis, is currently down due to a breakdown. But even if it was to be brought to life, it can only generate 30MW, although it can go up to 90MW everything being equal.
The Financial Gazette can reveal that ZRA, a joint venture outfit responsible for the management of water in the Zambezi basin, has been forced to reduce water allocation for electricity generation from 45 billion cubic metres per annum to 33 billion cubic metres due to low water levels in Kariba Dam following poor rainfall.
Water levels could also have been affected by a rise in development projects in the regional catchment, such as dam development, construction and agriculture.
Current water levels at Lake Kariba, the second largest man-made reservoir, have hit record lows, according to sources.
The Zimbabwe Power Company (ZPC) and Zambia Electricity Supply Corporation (ZESCO) share the water resource from Kariba Dam for power generation.
ZRA board chairperson, Emelda Chola, who is also permanent secretary in Zambia’s Ministry of Energy, Mines and Water Development, confirmed the development, saying both ZPC and ZESCO had been advised of the development and should adjust their operations.
“Contrary to regional and local (Zambia) weather forecasts of above normal rainfall for the October 2014 to April 2015 period, below normal rainfall has been received in the region leading to reduced Zambezi River flows and subsequent low inflows into Lake Kariba,” said Chola in response to questions from the Financial Gazette.
“In view of the current low Lake Kariba water levels recorded as well as the low Zambezi River inflows received at the Kariba Dam, it is necessary to reduce the water allocation for power generation to ensure continued power generation until the next rainfall season.
“Therefore, the authority has reduced the water allocation available for power generation at Kariba Dam from the original 45 billion cubic meters to 33 billion cubic metres,” she said from her base in Lusaka.
A poor rainfall season implies reduced river water in-flows into Lake Kariba which in turn reduces water available for power generation. This will result in low electricity generation at Kariba Dam.
The situation is likely to continue as the lower catchment rivers are particularly dry by August or September of every year.
Chola, however, said ZRA would continue to monitor the situation and carry out continuous reviews of water availability, making necessary adjustments to stay within the operating rules that govern the sustainable management and operation of Lake Kariba.
ZRA, established in 1987 as a successor to the Central African Power Corporation, is mandated to manage and harness the Zambezi River waters.
It also maintains the Kariba Dam complex which comprises the dam wall, Lake Kariba water storage reservoir and other associated ancillary facilities such as lake levels and river in-flows monitoring equipment.
ZRA is mandated to manage any future dams or infrastructure on the river forming a common border between the two countries.
Through the rule curve, ZRA determines water levels — that is the highest and lowest tolerable level — to which the Kariba Dam reservoir may provide firm loads of water for power generation.
“In line with the operating rules of the Kariba Dam reservoir and in an effort to avoid draining of Lake Kariba (which would lead to no generation of power from any of the two power stations at Kariba Dam), ZRA continuously monitors the Zambezi River levels and Lake Kariba water levels, as well as the water used for generation activities at the ZESCO Limited Power Station on the Zambian side and ZPC on the Zimbabwean side,” Chola said.
“To this end, sustainable operation of Lake Kariba implies that ZRA must implement measures to manage the reservoir in such a manner that ensures that water for power generation is available till the following rainy season,” she said.
Power generation at Kariba Dam relies on availability of adequate water which also depends on the rainfall received in any particular rainfall season.
Kariba South Power Station has remained Zimbabwe’s biggest generator of electricity.
The plant has been producing relatively cheap and reliable electricity for the country but is now unlikely to perform to its optimal due to reduced usage of water.
The reduction in water allocation for power generation is likely to result in intense load shedding throughout the country.
In the past five years, the Zambezi Basin has experienced above normal rainfall which effectively saw a progressive increase in water levels.
Zimbabwe has been experiencing crippling power shortages, with national demand at peak periods estimated at 2, 200MW, against available generation of about 1,000MW.
The country has been importing from regional power utilities to cover the shortfall, but this has also not been enough to meet demand.
Imports are currently only coming from Mozambique’s Hydro Cahora Bassa, which has been supplying a paltry 50MW but on a non-firm contract. What this means is that Hydro Cahora Bassa has been supplying Zimbabwe only when it has enough to do so.
Electricity supply was expected to be one of the key drivers of government’s economic revival strategies under the Zimbabwe Agenda for Sustainable Socio-Economic Transformation (Zim-Asset). Zim-Asset envisages increased access to electricity by domestic consumers, both within urban set ups and rural communities.
It is expected, in terms of the Zim-Asset vision, that existing power generation plants would be refurbished to boost internal power generation by 300MW by December 2015.
Part of that work started last year, with current refurbishment of Hwange Thermal Power Station.
Last month, a ZESA official told this newspaper that the group had approached Mozambique’s Aggreko to secure 150MW of gas-fuelled power for the local market to augment supplies This, he said, was part of a wider plan to secure 200MW from the regional power pool.
There have been calls for government to invest in solar technology to mitigate load shedding in the short term but studies by ZESA appear to suggest that the technology is expensive relative to investment utilisation levels.
The electricity situation has serious repercussions on the recovery of the productive sectors of the economy such as manufacturing, agriculture, mining and tourism, which government wants to drive the country’s economic recovery.
Presently, most households and industries in Zimbabwe are subjected to between three to five hours of load shedding daily.
Unstable power supplies are causing companies to incur heavy losses as some processes are interrupted thereby affecting the quality of products.
Some processes are also delayed or aborted resulting in failure to meet deadlines and targets for many companies.
Indeed, government, through ZPC, is working to close the electricity deficit in the country through the expansion of Kariba South Hydro Power Station to add 300MW to the national grid.
Work to expand Kariba by the winning bidder, Sino Hydro, is currently underway.
The country is also pursuing the Hwange Thermal Power Station expansion project which would see the country’s largest coal-fired power station adding two more units to give a combined generation capacity of 600MW.
It is also pursuing the Batoka Gorge power project along Zambezi River.
ZPC is also pursuing the establishment of solar power plants and has identified possible sites in Gwanda, Zvishavane, Munyati and Plumtree.
The Munyati and Zvishavane sites already belong to ZPC. ZPC is also planning a mini-hydro power station along the Gairezi River in Manicaland.
In February, Energy Minister Samuel Undenge said the power shortages should end in 2018. His prognosis was based on the finalisation of several power projects that are in the pipeline.