The Olkaria V geothermal power project is located approximately 120km north-west of Nairobi, Kenya. Images courtesy of Gesto-Energia S.A.
Kenya Electricity Generation Company (KenGen) is the owner and operator of the Olkaria V geothermal power station. Images courtesy of Gesto-Energia S.A.
The Olkaria V geothermal power project is developed with Japanese financial assistance. Images courtesy of Gesto-Energia S.A.

The Olkaria V is a 165MW geothermal power project located in the Greater Olkaria Geothermal Area in Nakuru County, Kenya, approximately 120km north-west of Nairobi.

Kenya Electricity Generation Company (KenGen), which owns and operates the existing Olkaria geothermal development, is also the implementing agency for Olkaria V.

Construction on the £470m ($669m) project was started with Japanese financial assistance in April 2017, while the first 82.7MW generating unit of Olkaria V was connected to the national grid in July 2019.

Commissioning of the similar capacity unit two of Olkaria V was, however, delayed due to an accident caused by the bursting of an under-construction steam pipeline that injured ten workers in July 2019. The commissioning process for Olkaria V unit-2 is in progress.

After achieving full capacity, the Olkaria V project is expected to increase KenGen’s total generation capacity at Olkaria to 676MW by the end of 2019.

Location and site details

The Olkaria geothermal field is located at an elevation of approximately 2,000m within the central Kenya segment of the East African Great Rift Valley, which possesses good deal of recoverable geothermal resources due to the intrusion of hot magma bodies up to less than 6km-deep beneath the surface.

The geothermal reservoirs for Olkaria are located at depths between 600m and 3km underground, and possess temperature as high as 350ºC.

Olkaria V geothermal plant details

The Olkaria V geothermal project comprises a steam gathering system, a power plant equipped with two steam turbine generators, and a substation and associated transmission line.

The 8in-diamter production wells drilled into the reservoir produce approximately 75% water and 25% steam, which are separated through cyclone separators in a nearby separator station.

Dry steam is piped to the power plant for generating electricity, while the separated water is injected back into the reservoir through injector wells.

The Olkaria V power plant is equipped with two 70MW class steam turbine generators from Mitsubishi Hitachi Power Systems (MHPS).

The exhaust steam from the turbines is sent to a main condenser and the resultant condensate is pumped to the cooling tower, to be recycled as cooling water.

The non-condensable gases (NCG) contained in the exhaust steam are extracted from the main condenser through ejectors and vacuum pumps and sent to the cooling tower fan stacks and dispersed into the atmosphere following diffusion with warm air.

Power transmission

The power generated at Olkaria V is transmitted from an onsite 220kV substation to the Olkaria IV switchyard through a 5km-long transmission line.

Financing for Olkaria V

The Japan International Cooperation Agency (JICA) provided ¥45.69bn (£283m) of Official Development Assistance (ODA) loan for the project under a loan agreement signed with KenGen in March 2016.

The remaining project cost was funded by the Government of Kenya as well as the Export-Import Bank of China.

Contractors involved in the Olkaria V geothermal power project

Mitsubishi Hitachi Power Systems (MHPS), in a consortium with Mitsubishi Corporation and H. Young & Company, an engineering and construction company based in Kenya, was awarded the full-turnkey contract for the Olkaria V power generation facilities in February 2017.

Sinopec International Petroleum Service Corporation, a subsidiary of China Petroleum & Chemical Corporation (Sinopec), was contracted for the steam gathering system of the Olkaria V project.

A joint venture of two more Chinese companies namely Sieyuan Electrical and North East China International Electric Power Corporation (NEIE) was responsible for the construction of the substation as well as transmission lines for the project.

A joint venture of Italian consulting firm Steam and Portugal-based company Gesto Energia was contracted to provide consultancy services for the design and implementation of the project in 2015.

Other geothermal power stations at Olkaria

The Olkaria I power station comprising three 15MW units commissioned in 1981, 1982 and 1985, respectively, was the first geothermal power facility to be developed in Africa.

The fourth and fifth units of Olkaria I with a combined generation capacity of 140MW were commissioned in February 2015. KenGen also plans to develop the sixth unit with an installed capacity of 83.3MW at Olkaria I.

The Olkaria II power station consists of three 35MW generating units. The first two units were commissioned in 2003 and the last one was brought online in May 2010.

The Olkaria IV power station consists of two units having a combined capacity of 140MW that were brought into operations in December 2014.

Ground-breaking ceremony for one of the two units of the future 140MW Olkaria VI project was held in December 2018. The Olkaria VI power station is scheduled to commence operations in 2022.