Place
Zambesi River - Zambia and Zimbabwe
Client
Zambezi River Authority (ZRA)
Year
2014 - 2019
Description for Batoka Gorge Hydropower (Zambia/Zimbabwe)
The prestigious project of Batoka Gorge, with its 2400 MW, will become the third largest hydropower plant in Africa and one of the sixty largest all over the world by generating capacity and its RCC concrete arch-gravity dam, with its 180 m, will be one the highest of its kind.
Batoka Gorge is located on the mighty Zambezi river, at the border between Zambia and Zimbabwe, about 50 km downstream of Victoria Falls and 120 upstream of Kariba reservoir.
The project has the scope to develop the first part (DH = 166.5 m) of the hydropower potential (DH = 280 m) between the Victoria Falls and the existing Kariba hydropower plant and is meant to address the power supply shortages that the two countries are facing, leaving also the possibility to export power production through the South African Power Pool (SAPP).
The peculiarity of this outstanding project consists of its trans-boundary nature, being the power plant foreseen to be equally shared among the neighbouring countries of Zambia and Zimbabwe.
The layout includes a roller compacted concrete arch-gravity dam, about 180 m high and 760 m long, creating the head available for power production and a quite small reservoir that allows a weekly regulation of the flows.
The dam body hosts on its central part a spillway divided into several independent channels controlled by gates, returning the floods into the river into a pre-excavated plunge pool in the riverbed, and two middle level outlets.
Two twin power plants are foreseen on the two banks, one for Zambia and one for Zimbabwe, each one comprising two underground waterways and an outdoor powerhouse disposed quite parallel to the steep rock front and slightly rotated with the river alignment.
Each of the four waterways is provided with relevant intake structure, concrete lined power tunnel, surge shaft and steel lined penstock ending into three manifolds that feed the relevant powerhouse.
The two power houses host No. 12 turbines (No. 2x6x200 MW) obtaining a total installed capacity of 2400 MW. Six main step-up transformers are located in “open air” at the back of each power house on a dedicated deck, and transmission lines will transfer the power to both countries.
Main Features
- RCC arch-gravity dam ( H = 175 m, L_crest = 720 m, V_rcc = 4 Mm³ )
- Spillway on dam ( Q = 20'000 m³/s, No. 11 radial gates, W x H = 12 x 18.5 m )
- No. 4 Headrace Tunnels ( D = 11 m, L = 500 - 800 m )
- No. 4 Surge Shafts ( D = 20 m, H = 85 m )
- No. 4 Penstock ( D = 8 m, L= 280 - 390 )
- No. 2 Power Houses ( No. 6 x 2 Francis turbines, Q = 1'645 m³/s, IP = 2'400 MW )
- Transmission Lines ( L = 200 km @ 330 kV in Zambia, L = 140 km @ 400 kV in Zimbabwe )
Engineering Services
- Pre-feasibility study (confirmation of layout)
- Feasibility study
- Tender design
- Tender documents