Paper Presented by At the Zambezi River Basin Stakeholder Conference : 22 – 23 Nov Windhoek, Namibia Eng. S. Z. Mhlanga Senior Manager (Projects & Dam Safety) ZAMBEZI RIVER AUTHORITY

Contents Brief Background Past Studies and Investigations Introduction Overview of the Hydropower schemes locations Concept of developing the total available head Features of the individual schemes Conclusion

Brief Background Power Developments on the Zambezi Sir Alexander Gibb & Partners and Merz McLellan January Feasibility Stage Site Investigations (Volumes 1 – 3) Sir Alexander Gibb & Partners and Merz McLellan Past Studies & Investigations

Brief Background (cont.) Phase IV Exploratory Drilling Works KW Blasting Batoka Gorge Hydroelectric Scheme Feasibility Studies Studies (Volumes 1 – 7) Batoka Joint Venture Consultants Further Environmental Impact Assessment Studies Civil Consult and Soils Incorporated 1998.

100m 900m Overview of the Schemes

ZAMBEZI RIVER Katombora Storage Reservoir only Vic. Falls North Bank Runoff River Scheme 10 x 9.8 MW generators Vic. Falls South Bank Runoff River Scheme 2 x 195 MW generators Batoka Runoff River Scheme 8 x 200 MW generators Devils Gorge Runoff River Scheme 8 x 155 MW generators Kariba Dam Storage Reservoir Kariba North Bank 4 x 150 MW generators Kariba South Bank 6 x 125 MW generators Kariba South Bank Ext. 2 x 150 MW generators Mupata Gorge Storage Reservoir 1000MW Generation Kariba North Bank Ext. 2 x 150 MW generators ZAMBEZI RIVER VICTORIA FALLS Existing Reservoir Planned Reservoir Existing Power Plant Planned Power Plant

Existing Reservoir Planned Reservoir Existing Power Plant Planned Power Plant Cabora Bassa South Bank 5 x 415 MW generators Mupanda Uncua Storage Reservoir 1600 MW generation Cabora Bassa North Bank 1200 MW total Cabora Bassa Storage Reservoir Boroma HES Storage Reservoir 444 MW generation Lupata HES Storage Reservoir 654 MW generation INDIAN OCEAN ZAMBEZI RIVER

KATOMBORA BARRAGE Katombora Rapids Flow Large lake surface area – 7,700 km 2 High evaporation losses 65 billion m 3 storage Located about 42km upstream of V/Falls

30m high RCC gravity Dam 3.2 km long dam wall  2km long ogee free-flow spillway Submerged sluice gates Project cost estimated at US$290 million

VICTORIA FALLS SOUTH BANK HES VICTORIA FALLS SOUTH BANK HES Runoff river scheme. Water extracted by intakes up stream of Falls. Conveyed by canals & tunnels to underground power stations downstream of Falls. Gross generation head of about 110m. Regulatory weir about 20km upstream of Falls to provide overnight storage  16 million m 3 For power station to operate during day without adverse effect to the flow over the Falls. Generation Capacity 390MW Specific generation cost 2.10 US cents/kWh Estimated project costUS$324 million.

BATOKA GORGE HES BATOKA GORGE HES RCC Gravity Dam 54km d/s of V-Falls 181m high dam wall Underground powerhouses. Underground transformer caverns. 800MW

Storage Capacity :1.68 billion m3 Reservoir contained entirely within gorge. Surface area at Maximum retention 25.6 km 2 Spillway : crest overflow ogee with 12 radial gates, 14m W x 13m H Specific Generation cost : 1.78 US cents/kWh Project Cost : US$ 2.5billion.

DEVIL’S GORGE HES DEVIL’S GORGE HES Runoff River Scheme Develops remaining head between Batoka and Kariba. Double Curvature Concrete Arch Dam Height : 140 m Storage : 1.7 billion m3 Spillway :  9No. submerged sluice gates (8.5m W x 9.5m H) Auxiliary Spillway :  5-Gate controlled Ogee crest overflow (14m W x 9m H) Underground Machine Halls Surface Transformer Compounds 620 MW Specific Generation Cost of 1.93 US cents/kWh. Estimated Project Cost of US$1.07 billion. Ranked second in priority of development after Batoka.

KARIBA SOUTH & NORTH BANK EXT. KARIBA SOUTH & NORTH BANK EXT. Power stations originally designed with scope for expansion. Extra 2 x 150MW turbines on either bank.  Added capacity will provide peaking power and reserve capacity  No increase in overall firm energy before construction of Batoka. Scope of works:  Excavation of new underground power caverns  Excavation of intakes, penstocks and tailrace tunnels.  Construction of surface transformer compounds.

90m high rock-fill dam favoured by geology of site. Storage : 19.8 Billion m 3 Reservoir would flood Mana Pools and part of existing game reserves. Generation capacity : 1000MW Specific Generation Cost : 2.02 US cents/kWh. Estimated Project cost : US$1.52 B. Mupata Gorge HES Mupata Gorge HES

CABORA BASSA NORTH BANK CABORA BASSA NORTH BANK Current generation only on South Bank. (2075MW) Potential of 1200 MW on North Bank. MUPANDA UNCUA, BOROMA, LUPATA MUPANDA UNCUA, BOROMA, LUPATA Will all operate from storage reservoirs Develop the remaining head between Cabora Bassa and the Indian Ocean. Mupanda Uncua :1600 MW Boroma :444 MW Lupata :654 MW

MUPANDA UNCUA, BOROMA, LUPATA MUPANDA UNCUA, BOROMA, LUPATA Power stations originally designed with scope for expansion. Extra 2 x 150MW turbines on either bank.  Added capacity will provide peaking power and reserve capacity  No increase in overall firm energy before construction of Batoka. Scope of works:  Excavation of new underground power caverns  Excavation of intakes, penstocks and tailrace tunnels.  Construction of surface transformer compounds.

Conclusion Existing Total Capacity (MW) Proposed additional Capacity (MW) 3,6158,488 Total potential :12,103 MW Percentage developed :30 %

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