The new 400 220kV Mariakani substation will provide stable and reliable power to homes businesses and industries across the coastal region. The project will strengthen the power transmission corridor from Nairobi to Mombasa and support Kenya’s clean energy and regional power integration goals. The investment, supported by the Government of Kenya and the African Development Bank, will strengthen confidence in the country’s energy infrastructure.
Kenya Electricity Transmission Company has supplied power to 400 220kV Mariakani substations, marking a major milestone in improving the reliability and stability of power along the coast.
The commissioning of the substation will end years of power insecurity in the region, benefiting households, commercial businesses, hotels, and both small and large manufacturing businesses. With improved connectivity to the national grid, coastal regions are expected to significantly reduce their dependence on expensive diesel generators.
The Mariakani substation will serve as a key power gateway linking the coast to the national grid in Nairobi. By strengthening this corridor with 400kV, KETRACO will enable a more reliable power supply, support industrial growth, attract new investment and improve the quality of life for millions of Kenyans.
The substation forms part of the Nairobi to Mombasa transmission line and is designed to transfer more than 1000MW of power between the two regions. This increased capacity reduces the strain on the coastal power network and improves overall system performance.
The project is also a strategic element to strengthen Kenya’s national electricity grid and wider regional interconnected power system. A stronger transmission grid is essential to realize the full operational benefits of the 500kV Ethiopia-Kenya Interconnector and the 400kV Kenya-Tanzania Interconnector.
Additionally, the Mariakani substation will support Kenya’s goal of achieving 100 percent clean energy by 2030. This will enable geothermal power generated by the Olkaria wind farm from the Lake Turkana Wind Power Project and an increase in the inflow of hydropower reaching the coast from Ethiopia.
“This development will significantly reduce the coastal region’s dependence on expensive and polluting diesel power generation, especially during evening peak hours. Cleaner, more reliable and consistent energy will flow more efficiently, reducing costs and stabilizing supply,” said Eng Kipkemoi Kibias, Acting Managing Director of KETRACO.
Financing for the Mariakani substation was provided through a partnership between the Government of Kenya and the African Development Bank at a total cost of 3 billion Kenyan shillings. China CAMC Engineering Company Limited was the implementing contractor under the supervision of KETRACO engineers. In addition to the substation, the African Development Bank is also the lead investor in the transmission line connecting Mariakani to Nairobi and Rabai.
The energization of Mariakani completes the second phase of the Mombasa to Nairobi transmission line project. The first phase involved the construction of a two-circuit transmission line from Nairobi’s Rabai substation to Embakasi substation, which began operations in 2017.
Both the 400kV Isinya and Mariakani substations have been completed and the entire 400kV Mombasa to Nairobi transmission corridor is now operational. The project will increase transmission capacity by more than 1000MW to the coast, reduce technical losses, lower power costs and provide a more reliable and resilient electricity network in line with Kenya’s clean energy transition.
Author: Brian Groenendaal
