POWER December 2016 - 30

TOP PLANTS
Gibe III Hydroelectric Project,
Southern Nations Nationalities
and Peoples' Region, Ethiopia
Owner/operator: Ethiopian Electric Power Corp.
Courtesy: Studio Pietrangeli
Building the 1,870-MW Gibe III hydroelectric project required unprecedented solutions
that took into account the remoteness of the site, the narrow gorge where the
dam is located, the height of the dam, and challenges in sourcing reliable materials.
Sonal Patel
S
plit almost diagonally by the East African
Rift System, Ethiopia is a rugged
geological wonderland of mountain
ranges and basins. Etched with large river
gorges, and with a rainy season that lasts
three to four months, the country has an
overall hydroelectric potential estimated at
around 160 TWh/year.
Although the landlocked country only has
about 2.3 GW of installed capacity (86% of
which is hydropower) to serve its population
of more than 95 million, the government of
Ethiopia is on a drive to exploit this massive
potential. Under its latest Growth and Transformation
plan, the country wants to increase
capacity to 10 GW by 2018, to 17 GW by
2020, and to 35 GW by 2037 to sustain soaring
economic growth and make Ethiopia a
renewable power hub in East Africa.
Among key projects is the 1.8-GW Gibe III
(also known as Gilgel Gibe III) in Ethiopia's
southwestern Southern Nations Nationalities
and Peoples' Region. The project is located
on the Omo River, a 760-kilometer (km)30
long
perennial body of water that rises in the
Shewan highlands and snakes southward until
finally emptying into Lake Turkana on the
border with Kenya. Long considered a hydro
powerhouse, Ethiopia started construction
on the first dam on the Omo River-Gilgel
Gibe I-in 1986. The 184-MW rock-filled
embankment dam wasn't completed until
2004, but it spurred the start of construction
for the 420-MW Gibe II in 2005. That project,
which has a 50-meter (m)-high gravity
dam and Pelton turbines, was completed in
2010 with the technical backing of Italian
construction and civil engineering firm Salini
Impregilo.
Kicking off the Third Phase
In 2006, while construction for Gibe II was
ongoing, Ethiopian Electric Power (EEP),
a government-owned enterprise that is the
sole provider of most of Ethiopia's bulk
power, awarded Salini Impregilo an engineering,
construction, and procurement contract
for the third project on the Gibe-Omo
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hydroelectric cascade, Gibe III. Studio Pietrangeli,
another Italian firm that provides
specialized consulting engineering services
for hydropower, designed the
innovative
project that would become the biggest engineering
structure in the history of Ethiopia
and provided a feasibility study and technical
supervision during construction. French
company Tractebel Engineering provided
project management services, including review
of the feasibility study and basic design,
supervision of design and construction, and
development and implementation of the environmental
management plan.
The companies eventually selected a dam
type based on the site's unique conditions.
The project is sited 150 km downstream from
Gibe II in an area where the Omo River flows
through narrow valleys and deep canyons
(Figure 1). This was favorable to construction
of a reservoir with a capacity of 14 cubic
km (designed to enable flood regulation), but
it presented " extremely challenging logistical
conditions for dam construction, " said
POWER | December 2016
http://www.powermag.com
POWER December 2016

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