Kenya Commissions 400/220 kV Mariakani Substation to Strengthen Coastal Power Supply
On May 25 2026, President William Samoei Ruto officially inaugurated the upgraded Mariakani substation in Kilifi County, marking a milestone in Kenya’s effort to modernise its national transmission network. The facility, now operating at 400 kV / 220 kV, was built by the Kenya Electricity Transmission Company (KETRACO) with financial backing from the Government of Kenya and the African Development Bank (AfDB).
Project Overview and Financing
The Mariakani upgrade formed part of a broader initiative to reinforce the Nairobi‑Mombasa transmission corridor. Total project costs amounted to approximately KES 4 billion (≈ US $28 million), funded through a sovereign‑guaranteed loan from the AfDB and counterpart financing from the Kenyan Treasury. Engineering, procurement and construction were carried out by China CAMC Engineering Co. Ltd, while KETRACO engineers provided on‑site supervision and quality assurance.
The substation was originally commissioned as a 220 kV station in 2021. In December 2025 the voltage level was raised to 400 kV, enabling the line to carry higher power flows with reduced losses.
Technical Upgrades and Grid Impact
Key technical improvements include:
- Installation of a 400 kV double‑circuit busbar system.
- Replacement of legacy transformers with higher‑efficiency units.
- Integration of advanced SCADA monitoring for real‑time voltage regulation.
- Construction of the 400 kV Mariakani‑Isinya double‑circuit transmission line, which links the coast to the inland grid via the Suswa switching station.
These upgrades have markedly improved power quality across Kilifi, Mombasa and Lamu counties. According to KETRACO’s post‑commissioning report, voltage fluctuations have dropped by more than 40 % and fault clearance times have been reduced from an average of 300 ms to under 150 ms.
Economic and Environmental Benefits
Before the substation’s upgrade, the coastal region relied heavily on diesel‑fuelled thermal generators to meet peak demand. Data from the Energy and Petroleum Regulatory Authority (EPRA) show that thermal output fell from 100 MW to 35 MW after the substation went live in December 2025—a 65 % reduction in fossil‑fuel‑based generation.
This shift translates into lower fuel import bills, estimated at roughly KES 1.2 billion per year, and a corresponding decrease in carbon dioxide emissions of about 0.8 million tonnes CO₂‑equivalent annually. The enhanced transmission capacity also supports the government’s Vision 2030 target of achieving 100 % renewable electricity by facilitating greater inflow of geothermal and wind power from the Olkaria and Suswa complexes.
Industry stakeholders anticipate that the stronger grid will unlock new investments in the blue economy—particularly in fish processing, port logistics and tourism—by providing reliable, competitively priced electricity to industrial zones along the coastline.
Statements from Leadership
During the commissioning ceremony, President Ruto emphasized the strategic nature of the project:
“My government is committed to introducing innovative, clean and sustainable energy technologies that drive economic growth while protecting our environment. Projects like the Mariakani substation are critical to strengthening our national grid, expanding access to reliable electricity and advancing Kenya’s vision of achieving 100 % clean energy.”
— President William Samoei Ruto, May 25 2026
Eng. Kipkemoi Kibias, Acting Managing Director of KETRACO, added:
“The Mariakani transmission infrastructure has significantly reduced the coastal region’s dependence on expensive diesel‑powered generation by enabling efficient power transfer between Nairobi and Mombasa via the 400 kV dual‑circuit line. Voltage stability and overall power quality have improved, delivering a more reliable supply for homes, businesses and industry.”
— Eng. Kipkemoi Kibias, KETRACO
The successful delivery of the Mariakani substation underscores Kenya’s growing capability to execute large‑scale transmission projects through international partnerships and local expertise. As the country continues to integrate renewable resources into its grid, upgrades such as this will remain essential for ensuring that clean power reaches every corner of the nation.
