Kenya: Major substation launched for Coastal region

KETRACO said the substation will additionally play a key role in the country’s push toward 100% clean energy by 2030

Kenya has energised the 400/220kV Mariakani Substation, a development aimed at delivering electricity to homes, businesses, hotels and small- and large-scale manufacturing industries across the country’s Coastal region.

The Kenya Electricity Transmission Company (KETRACO) said the facility will end years of power instability in the region and will reduce dependence on costly diesel generators. 

Substation to play major role in Kenya energy landscape

KETRACO said the Mariakani substation is a critical power gateway linking the Coast to Nairobi’s national transmission grid, with reinforcement at 400kV unlocking a more stable electricity supply to support industrial growth, attract investment and improve daily life for millions of Kenyans.

“The energised Mariakani substation forms part of the Nairobi-Mombasa Transmission Line, designed to carry more than 1,000MW electricity between the two regions and ease pressure on the Coast’s power network.

“The 400/220kV Mariakani Substation is a strategic component in reinforcing Kenya’s national power transmission grid, which underpins the strength of the regional interconnected power system. 

“Strengthening the grid is essential to fully realise the operational benefits of the 500kV Ethiopia-Kenya and 400kV Kenya-Tanzania Interconnectors.”

Substation to reduce diesel reliance

KETRACO said the substation will additionally play a key role in Kenya’s push toward 100% clean energy by 2030, allowing more geothermal power from Olkaria, wind power from Lake Turkana Wind Plant and hydro power from Ethiopia to reach the Coast region.

“With this development, the Coast will significantly reduce its reliance on expensive and polluting diesel power, especially during peak evening hours. Cleaner, reliable and stable energy will now flow more efficiently, lowering costs and stabilising supply,” said KETRACO Acting Managing Director Kipkemoi Kibias. 

Financing for the Mariakani Substation was provided through a partnership between the Government of Kenya and the African Development Bank (AfDB) at a cost of KSh3 billion (around $23.2m). 

China CAMC Engineering Company were the implementing contractor for the project and supervised by KETRACO engineers. 

Transmission line build out

Beyond the substation, AfDB is also the lead financier of the transmission lines linking Mariakani to Nairobi and Rabai. These include the 400kV double-circuit transmission line from Isinya to Mariakani and the 220kV double-circuit line from Mariakani to Rabai. 

KETRACO said the Mariakani Substation completes the second phase of Mombasa-Nairobi Transmission Line Project. 

Project details:

Phase 1

• The first phase included the double circuit transmission lines from 220kV Rabai Substation to 220kV Embakasi Substation near the Internal Container Deport (ICD) in Nairobi. 
• The double circuit transmission line was designed for 220kV between Rabai Substation to Mariakani Substation and 400kV from the Mariakani Substation to 220kV Athi River Substation through the 400kV Isinya Substation, then 220kV between Athi River Substation to 220kV Embakasi substation through a 6.7km, 220kV Underground Cable through the Nairobi National Park. 
• The total length of the transmission line from 220kV Rabai Substation to 220kV Embakasi Substation is 492km.  
• The transmission line has been operating at 220kV voltage level since 2017. The total cost of the first phase of this project was KSh17 bn (around $131.7m) being jointly financed by the AfDB, the European Investment Bank and the French Development Agency and the Government of Kenya.

Phase 2

• Phase II of the project was to construct the two Substations of 400/220kV Mariakani and 400/220kV Isinya with the goal of upgrading the transmission line capacity between the two substations by raising the voltage from 220kV to 400kV. 
• 400kV Isinya Substation was completed in 2022 and with the 400kV Mariakani Substation being energised, the cycle of the entire 400kV Mombasa-Nairobi Transmission Line comes to an end with the benefits of increased transmission line capacity to the coastal region of more than 1,000MW of clean electrical energy from hydros, geothermal and wind, reduced technical power losses thus reducing the cost of power, reinforcement of the coastal power grid thereby improving the system reliability and stability. 
• Phase II of this project cost KSh 7bn (around $54.2m).

“Beyond boosting power supply, the project improves power quality, reliability and grid stability, ensuring the Coast region is fully integrated into Kenya’s modern, clean and resilient electricity network,” said KETRACO.

Cover photo:  : The recently energised 400/220kV Mariakani Substation. Source: KETRACO/X