Ok Menga – rehabilitating an ageing hydro power station

Client: Ok Tedi Mining Limited (OTML)
Location: Tabubil, Western Province, Papua New Guinea
Date: October 2012- ongoing

Rehabilitating, modernising and upgrading an existing hydropower station to remedy risks and extend useful asset life


Ok Tedi Mining Limited (OTML) has operated the Ok Tedi mine in the Star Mountains region of Papua New Guinea since 1984.  The mine and local township rely on the run-of-river Ok Menga hydropower station for 75% of their power. When the life of the mine was extended, OTML engaged Entura to advise on necessary actions to rehabilitate, modernise and upgrade the ageing power station and to provide training and skill development for staff of OTML’s generation operation.


Entura applied its best-practice asset management approach at Ok Menga by thoroughly assessing the condition, performance and remaining useful life of all aspects of the station, including all electrical, mechanical, and civil assets. Entura developed a risk and mitigation plan including urgent actions to remedy serious risks and ‘quick wins’ to improve the state of the station quickly, economically and effectively. Entura’s approach optimised capital and operational costs over the remaining asset life, and identified efficiency and capacity gains.

To improve the risk-position of the power station, Entura instigated the following actions:

  • main inlet valve and turbine governor fault finding and troubleshooting following failures
  • turbine governor replacement and detailed integration design
  • generator synchroniser replacement and detailed integration design
  • main inlet valve replacement and detailed controls and integration design
  • cooling water system upgrade detailed design
  • control system PLC upgrade detailed design
  • electrical protection system detailed design
  • operator training, access and isolations, review and development of station routines, review of condition monitoring practices and systems.


Entura‘s hydropower expertise in condition assessment, risk assessment, asset management, and condition monitoring and operation helped the owner of the Ok Menga power station develop a plan for cost-effective and practical solutions to extend the life and improve the performance of the station, lower safety risks and increase staff skills, and reduce the significant commercial risks of costly outages.

Entura’s involvement has assisted the client reduce immediate and longer term risks to a level acceptable to the business, saved the owner the time and cost of developing its own programs, and increased the knowledge and skills of local staff.