Ramu 1 Power Station condition assessment and upgrade

Client: PNG Power Limited
Location: Eastern Highlands, Papua New Guinea
Date: 2005 - 2015

Upgrading and modernising a hydropower station to increase generating capacity, availability and reliability


Situated in the eastern highlands of Papua New Guinea, Ramu 1 is an underground power station with three 17.2 MW hydro generating sets installed in 1976 and two additional 15 MW sets installed in 1989/90 at the time that Yonki Dam and reservoir were created. Ramu 1 is the major electricity generator on the PNG northern grid and is critical for supplying electricity demand and also for offsetting expensive diesel power generation which is the only alternative.

The station’s power output had been restricted, with its maximum output reduced from an installed 75 MW to around 50 MW due to breakdowns and unit operating limitations. The reliability and availability of the generating units was poor.


Entura has been involved in the ongoing investigation and implementation of upgrades for PNG Power Limited (PPL) at Ramu 1 over more than ten years.

An initial condition and risk assessment study planned for appropriate future refurbishment and upgrade projects. This was followed by development of terms of reference for a number of upgrades on the generating units, their auxiliaries and on station ancillary services.

Entura assisted PPL with contractor negotiations and contract documentation for the rehabilitation project and a contract was awarded by PPL to Andritz Hydro. Entura provided a contract engineer and engineer’s representative in accordance with the international FIDIC terms and conditions.

Entura was also involved with a reservoir sedimentation assessment, catchment analysis options, review of the hydrographic network and hydrology, tailrace tunnel headloss testing and hydraulics assessment, and an electrical load flow study for the Ramu 1 transmission system.

Entura has also provided a contracted station manager for Ramu 1 Power Station.


The benefit to the Ramu 1 station owner (PPL) will be increased reliability and availability of the plant leading to a more reliable electricity supply and an increased amount of energy generation. This is vital for satisfying the load growth on the power system and will enable new major customers to be connected. It will also minimise the requirement for expensive diesel power generation.