Mainga Dam
Masinga dam, located on the border of Machakos and Embu, is the prime water reservoir for Kenya’s main hydropower circuit

This is the third bid that KenGen is making to raise the Masinga dam wall, after the previous attempts were suspended over its economic viability. Previous failed attempts to raise the Masinga wall was also due to a revenue dispute between KenGen and Tana and Athi Rivers Development Authority (Tarda), which owns the dam. KenGen owns the power generating equipment at Masinga and pays fees to the local authority for use of the dam’s infrastructure.
Cost of the project stood at Sh1.5 billion ($15 million) when it was last suspended in 2013 when it was due for a raise by 1.5 metres. The revised two metres extension is set to cost more. KenGen announced the plans after it sealed a financing deal with French Development Agency (AFD), which is funding the project as part of a wider plan to increase the capacity of Kenya’s hydropower plants to produce more electricity throughout the year.
“We plan to raise the Masinga dam wall by two metres,” KenGen managing director Rebecca Miano said.
The power producer said the French agency had handpicked French company EDF Group to conduct a feasibility study that would guide the developers on the upgrade of key dams. The study will cost Sh21 million (€169,000) and will take seven months, paving the way for actual works to begin.
Masinga dam, located on the border of Machakos and Embu, is the prime water reservoir for Kenya’s main hydropower circuit, the Seven Forks hydropower complex on Tana River and has a series of major hydroelectric power plants. Mrs Miano said the wall extension would enable the dam store more water during heavy rains and ensure a steady output of hydropower even during prolonged drought. Hydropower remains Kenya’s cheapest source of electricity.
Heavy rains occasionally cause the dam, standing at a height of 60 metres, to overflow when the water hits the maximum level, leading to loss of over 100 million litres, a resource the raised wall will conserve. During dry spells, water levels in Kenya’s hydroelectric dams often plummet, as is currently the case, cutting hydropower output and triggering an increase in the use of expensive diesel-generated electricity as an alternative.
This often raises power bills for homes and businesses since the available hydroelectric energy, relatively cheaper, is not sufficient and only meets about half of the economy’s power needs.
KenGen, listed on the Nairobi Securities Exchange (NSE) and 70 per cent owned by the government, is also moving to adopt pumped storage hydropower, the first in East Africa.
Under the plan, widely practised in the United States and Europe, the stored water is pumped in a cycle between dams, during night-time and weekends when electricity demand is rock-bottom, with one dam located below the other.
During peak demand, the stored water is released through turbines, flowing downhill from the upper reservoir into the lower – generating electricity.
This arrangement is expected to work well at the Seven Forks cascade, since Masinga, the first of dam in the cascade, sits on a higher ground.
KenGen’s Forks Hydro stations on Tana River include Masinga power station (40 megawatts), Kamburu (94 megawatts), Gitaru (225 megawatts), Kindaruma (72 megawatts) and Kiambere (168 megawatts).
KenGen first attempted to raise Masinga dam’s full supply level in the 1990s when it hired consultancy firm Knight Piesold to conduct an environmental impact assessment (EIA) study for the project.

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