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Prospect Mini Hydro: Remediation Works

Sydney Water Corporation (Sydney Water) is the largest water utility in NSW, providing water treatment and wastewater services to Sydney and outer suburbs and the Illawarra. In 2007, Sydney Water undertook a renewable energy program that included installing a 3.7 MW hydro power station at the outlet works of the Warragamba pipeline, before the Water Filtration Plant at Prospect. The hydro generator, as installed was treated as a flow delivery device by Sydney Water and generates whenever flow is available through the pipeline.


The generator, when P.E.T. and Stark Engineering Consulting were engaged, had only 5,400 hours of runtime in the four years since original commissioning. Several failures had occurred and confidence had been lost in its ability to reliably deliver flow and generate power.

Stark's Role
As part of the REG O&M contract (see here), Sydney Water engaged P.E.T. and Stark Engineering Consulting to investigate the plant's condition and propose a remediation strategy. Stark EC provided technical engineering, drafting and project management services for the both the initial investigation and the execution of the project. P.E.T. provided the necessary fabrication and installation works, as well as expert advise on bearing technology.


Responsibilities for the Prospect remediation program included:

  • Project scoping, budgeting and management. Stark EC adopted a multi-criteria assessment approach to identify and evaluate several potential options for project delivery

  • Documentation: Stark EC prepared specifications and RFQ documentation for consulting, technical and fabrication of new parts and services.

  • Risk workshop and option analysis

  • Failure workshop, which brought specialist hydro consultants into the room after a desktop study to determine the root causes of previous failures

  • Re-design of the mechanical seal flushing arrangement

  • Re-design of the runner end bearing arrangement

  • PLC modifications and control modification

  • Testing and commissioning

The re-engineered non-drive bearing assembly is considered a fit-for-purpose solution. Current runtime has already exceeded the lifetime of the previous bearing.


As a result of the remediation works, the hydro-turbine has been proven reliable and is contributing significantly towards Sydney Water's renewable energy target. P.E.T., together with Stark EC have been able to restore confidence in the plant by the asset owners.

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