Mount Mulanje, Malawi, Africa

Commissioning of the Ruo-Ndiza hydro power station in Mulanje, Southern Malawi was completed by Gilkes engineers in early 2020.

The run-of-river project, on the river Ruo at the foot of Mount Mulanje, was carried out on behalf of Mulanje Renewable Energy (MRE) in two phases over two years.  The contract, which was awarded in mid-2018, involved the installation of three horizontal Pelton turbines in the same powerhouse. The first phase of the project was installed and commissioned in 2018 with a 3.4MW Pelton turbine using the flow from the river Ndiza, with 2 further 3.3 MW Pelton Turbines being installed and commissioned earlier this year harnessing the flow of the river Ruo.  The schemes are located on the Lujeri tea estate where Gilkes have a long history of hydropower, installing turbines here as far back as 1934.  

The civil works and grid connection were carried out by MRE, a local IPP, with the support of Gilkes Hydro. The Ruo Ndiza plant is designed to generate average annual output of 22.3 GWh for supply to the national utility, ESCOM.  The system has been designed and installed to allow Black Start and run islanded. This provides support to the ESCOM grid and ensures that the Lujeri Tea Estate can maintain production with a reliable and stable power supply.  When running at full power, the system accounts for ~3% of Malawi’s total grid power.

The greenfield project replaces two existing schemes totalling around 700 kW on the Lujeri Tea Estates, that is owned by the UK-based agri-business PGI.  Four of the five turbines at the two powerhouses, situated on the estate, were equipped with turbines previously supplied by Gilkes that had been operated well beyond their design lifetimes. The first turbine was installed in the Ruo powerhouse in 1934 to supply power to the tea factory and for domestic use with a further two installed in 1946 and 1957. An additional unit was installed in the Lujeri plant in 1957.

To date Gilkes has supplied a total of 16 turbines to the southern African state, with the first supplied in 1901. 

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Key Stats

  • Commissioned Feb 2020
  • Installed Power 10 MW
  • Net Head 250 m & 275 m
  • Flow both at 1500 l/s
  • Turbines 3 x 1075mm Twin Jet Pelton

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