Power Transmission & Distribution System
Electricity transmission is the process by which large amounts of Electricity produced at power plants (such as hydro, geothermal, thermal and wind), is transported over long distances for eventual use by consumers. Due to the large amount of power involved, and the properties of Electricity, transmission normally takes place at high voltage (132-kilovolt or above) to reduce losses that occur over long distances.
Electricity is usually transmitted to a substation near a populated area. At the substation, the high voltage Electricity is converted to lower voltages suitable for consumer use, and then transmitted to end users through relatively low-voltage Electricity distribution lines that are owned and operated by the national Electricity utility. In Kenya, Kenya Transmission Company (KETRACO) Limited, 100% state owned corporation incorporated, in 2008 has been mandated to plan, design, construct, own operate and maintain high voltage electricity transmission grid and regional power interconnectos infrastructure that will form the backbone of the National Transmission Grid.
In carrying out this mandate, the Company is expected to develop a new and robust grid system in order to:
- Improve the quality and reliability of electricity supply throughout the country;
- Provide electricity to areas that are currently not supplied from the national grid;
- Provide a link with neighboring countries in order to facilitate power exchange and develop electricity trade in the region;
- Reduce transmission losses that currently cost the country about US$17 million per year; and
- Reduce the cost of electricity to the consumer by absorbing the capital cost of transmission lines since they will be fully funded by the government of Kenya.
The voltage rating of the transmission lines include 132kV, 220kV, 400kV and 500kV (HVDC) covering *** km of which 2,364km is owned and operated by KETRACO.
Kenya’s existing transmission lines and substations together with their transformation capacity is as provided.
Table: Kenya’s existing substations together with their transformation capacity
|Item||Substation Name||Voltage Levels||Transformation Capacity, MVA||Total MVA Capacity|
Table: Kenya’s existing transmission lines with respective loading
|Voltage(kV)||Line Designation||Number of circuits||Conductor||Thermal rating (MVA) - 100% Loading||Rating (MVA) - 80% Loading|
|132||Mwingi - Garissa||S/C||ACSR Lynx||112.9||90.3|
|132||Chemosit- Sotik||S/C||ACSR LGJ-300/50||150||120|
|220||Rabai-Kakuyuni (Malindi)||S/C||ACSR DIN-300/50||255||204|
|220||Kakuyuni (Malindi)-Garsen||S/C||ACSR DIN-300/50||255||204|
|220||Olkaria IV - Suswa||D/C||ACSR Canary||326||260.8|
|220||Olkaria I AU - Suswa||D/C||ACSR Canary||326||260.8|
|220||Suswa - Isinya||D/C||ACSR Condor||1648||1318.4|
|220||Isinya - Rabai||D/C||ACSR Lark||1449||1159.2|
|220||Olkaria II - Olkaria 1AU||-||-||-|
S/C – Single Circuit,
D/C – Double Circuit
In the 2018-2038 Transmission Master Plan, KETRACO Plans to construct an extra 8469KM of transmission lines.
Planned Expansion of Transmission Network
Kenya is working towards interconnecting with its neighbors in the Eastern Africa Power Pool. As part of the plan a number of transmission lines are being developed.
132km 400kV Lessos-Tororo line (Kenya – Uganda Interconnector)
This is a double circuit transmission line that evacuates up to a maximum of 1,200MW from the existing Lessos substation (Kenya) to the Kenya – Uganda border near Tororo substation (Uganda).
It is currently operating at 220kV but will be upgraded to 400kV to facilitate higher power transfer.
It is a part of the interconnection of Electric Grids of the Nile Equatorial Lakes Countries Project (NELSAP).
This cross boundary energy trade will in the long run facilitate power trade within the countries in the Eastern Africa Power Pool (EAPP). It is currently 55% complete.
612km 500kV Eastern Electricity Highway Project (Ethiopia – Kenya Interconnector)
This is a HVDC bi-pole transmission line that will evacuate up to a maximum of 2,000MW from the 400kV substation at Wolayta-Sodo (Ethiopia) to the Suswa 400kV substation (Kenya).
It will enable power trading within the Eastern Africa region and eventually to the Southern Africa Power Pool (SAPP). It is currently 98% complete with the estimated completion date being 31st October 2020.
96km 400kV Kenya – Tanzania Interconnector
This is the Kenyan component of a 2000km double circuit transmission line that will run from Isinya (400kV substation) through Namanga (400kV substation) to Arusha, Tanzania to Zambia. It will act as a link to the SAPP providing opportunities for power trade between SAPP and EAAP. It is currently 67% complete with the estimated completion date being 30th June 2021.