The existing Gogo hydropower plant is located in the Migori district of southwestern Kenya at the Kuja River near Lake Victoria. The Gogo hydro power station, which was comissioned in 1958, has a drop height of about 20 m and a current design discharge of 11 m³/s. The current installed capacity of the powerplant is 2 MW.
The power plant consists of a gravity dam, an underground power conduit with surge tank and a power house with two identical Kaplan turbines. The water for the power plant operation is taken from the Kuja River, which is impounded by the gravity dam.
During the power plant operation, which has now lasted over more than six decades, the reservoir has almost completely silted up, which leads to an impairment of the plant's energy production, especially in dry seasons. In addition, the entire machine and electrical system technology, such as turbines, generators and locking elements, is very outdated and damaged.
For these reasons, only about 1 MW of power plant capacity can currently be generated. In addition, the 33 kV transmission line, which is about 20 km long and connects the powerhouse to the Awendo substation, suffers frequent outages, sometimes several times a day. The state-owned energy supplier and operator Kenya Electricity Generating Company (KenGen) intends to renew and expand the power plant site in order to meet the increasing energy demand in the agricultural region of southwest Kenya.
To this end, KenGen, in cooperation with the Delegation of the European Union to Kenya (EU), initiated the project of a pre-feasibility study for the upgrading of Gogo Hydropower Plant. In April 2019, the Consortium SAFEGE – Tractebel Hydroprojekt GmbH was commissioned to carry out this pre-feasibility study. The aim of the study was to determine the optimum degree of capacity upgrade for the Gogo power plant site.
For this purpose, investigations on hydrology, geology and geotechnics were carried out as a basis for the technical design. A local subcontractor carried out additional on-site surveys for the consortium.
Subsequently, numerous technical variants were developed for the upgrade and redevelopment of the plant. Thus, various dam and powerhouse locations, different types of dams and dam heights as well as different design discharges and turbine types were examined in detail.
The pre-feasibility design showed that an upgrade of the Gogo hydropower plant with a maximum increase of the installed capacity to up to 20 MW is possible.
With the involvement of local engineers, further studies on the energy market and the electricity grid system in Kenya, as well as on the environmental and social impact of the project (PESIA-Study) were carried out. During the design phase, numerous site visits were also undertaken by the engineers from Tractebel. The study has been in its final phase since December 2019. The final presentation of the study to the clients KenGen and EU in Nairobi is scheduled for mid-January 2020.
Matthias Feldmann – München