Rouna 2 – upgrade of underground hydropower station

Client: PNG Power Limited
Location: National Capital District, Papua New Guinea
Date: January 2005 – February 2009

Upgrading and modernising an ageing underground power station for improved performance, increased safety and reduced risks from flood and fire


Rouna 2 is one of four hydro stations on the Laloki River in Papua New Guinea. It has five generating units and an underground machine hall dating from the 1960s. By the time this upgrade project was initiated, Rouna 2 was old and run down, presenting risks to workers and to its owners. The generating sets had reliability and availability problems and required refurbishment.


Entura was engaged to upgrade and modernise the station. Three of the turbines and generators were replaced with new uprated units, one was refurbished and upgraded and retained for backup, and one was retired from service. New controls and protection for the operating generating units and for the station were also installed.

The steel-lined penstock and tailrace were investigated and documented with recommendations for refurbishment.

Station auxiliaries were upgraded, including clean water supplies, fire detection and protection, cranes and hoists, and ventilation. A new station SCADA system was implemented.

Technical innovations included new methods for smoke control in event of a fire, and integration with the station’s ventilation system. An alternative exit was also created, using an emergency escape route via the tailrace surge shaft and tailrace tunnel.


The upgrade and rehabilitation has significantly improved the condition and operation of this important hydro asset. Entura’s expertise in project management, engineering, and contract management, and our ability to draw on our extensive experience of new hydro developments as well as maintenance and refurbishment, were integral to the project’s success.

The extension of the life of the Rouna 2 power station through upgrade and refurbishment has restored the full generating capacity of the station, reducing shortfalls in hydro generation that were previously met through expensive diesel generation. Another important outcome has been significant reductions in safety risks and hazards, greatly improving the safety of staff, contractors and visitors.