Oromia region – Ethiopia

Gibe V Multi-Purpose Project

Engineering for building a hydropower plant and irrigation purposes

Oromia region – Ethiopia

Gibe V Multi-Purpose Project

The Gibe V (660 MW) multipurpose project is the fifth and last stage of the Gibe-Omo hydroelectric cascade, following Gilgel Gibe, Gibe II, Gibe III (all operating) and Koysha (under construction).
It is the final step in the development of the entire hydropower potential of the Omo river and represents a realization of the large-scale vision started more than 25 years ago with the design of the Gilgel Gibe hydroelectric power plant.
Moreover, its multi-purpose reservoir allows also the use of regulated waters for the irrigation of a large area identified by the Environmental Study favouring the development of the local community.
The project is located approximatively 70 km downstream of Koysha and with its 660 MW of installed power will be able to produce approximately 2’000 Gwh/y.

The dam is an RCC gravity type with a maximum height of about 63 m, a crest length of about 580 m and an overall volume of approximately 400’000 m3.
A large spillway is incorporated in the central part of the dam body constituted of an overflow crest divided into ten bays and controlled by radial gates. The smooth chute ends in a stilling basin, foreseen for energy dissipation.
Cofferdams, culverts and low blocks are envisaged for river diversion on the left side of the river. During river diversion, the water flow will be controlled by the u/s reservoirs (Gibe III and Koysha). As a consequence of this control, the peak flow is substantially reduced and will be diverted by large culverts and over a “low block”.
The power penstocks are incorporated into the dam body and the powerhouse is located at the dam toe. Due to the presence of the wide energy dissipator, the outdoor powerhouse is divided into two sections of six turbines each. Access from one section to the other is guaranteed by a gallery under the energy dissipator, into the downstream toe of the dam body.
Due to the particular situation, a small gantry crane is envisaged in each section while a large outdoor gantry crane will serve both sections of the powerhouse. Between the two sections, the crane will run over rails on a bridge over the energy dissipator.

Oromia region - Ethiopia

PLACE

Salini Costruttori S.p.A.

CLIENT

2008 – 2009

YEAR

Main Features

RCC Gravity Dam (H = 63 m, L_crest = 580 m)

Spillway on dam body (N° 10 gates, W x H 12×19 m)

River Diversion Works (No. 2 culverts, D = 12 m, L = 240 m)

Dam body powerhouse (No. 12 Francis turbines, IP = 12×55 MW)

Switchyard (350 x 150 m, 400 kV line bays)

Oromia region – Ethiopia