Thorndon Cook Power
Thorndon Cook Power
Thorndon Cook Power
Wayang Windu Geothermal Power Station

Wayang Windu Geothermal Assets Due Diligence

Wayang Windu Geothermal Assets Due Diligence

The Project

Thorndon Cook Power staff were engaged by The Electricity Generating Public Company Limited (EGCO - Thailand) to provide an objective and independent technical assessment of the geothermal assets owned by Star Energy Company Pte Ltd. Two Due Diligence Reports were provided to support EGCO - Thailand in their valuation of the Wayang Windu geothermal assets and with the preparation of their bid to acquire a shareholding position within Star Energy Company Pte Ltd.

The Wayang Windu power station comprises two geothermal generating units with a rated gross electric generating capacity of 110 MW for Unit 1 and 117 MW for Unit 2. It includes a steamfield above ground system (SAGS), geothermal wells (production and injection wells) and all ancillary buildings, facilities and equipment. It is located near the town of Pangalengan in West Java, Indonesia

Our Role

As part of the due diligence investigation, our role was to undertake a critical analysis of all the technical documents given by EGCO - Thailand and Star Energy Company Pte Ltd. The analysis covered existing (Unit 1 & 2) and future (Unit 3 & 4) assets and included:

  • a review of the geothermal resource, its size and characteristics, whether the current proven resource area appears able to sustain production for Units 1 and 2 at current levels through the target date of 2049, the estimated average well capacity of future wells, and the estimated capacity of the inferred resource to support the proposed Units 3 and 4.
  • a condition assessment of the existing and future infrastructures including steamfield above ground system (SAGS) and power station, assessment of the future upgrades and rehabilitations for Units 1 and 2 and Capex and Opex estimates for Units 3 and 4.
  • evaluation of historical pant performance and reliability and assessment of future projections
  • a review of historical and near-term projected O&M and G&A budgets for station and steamfield
  • a review of existing and required permits, concessions and contracts
  • A review of site staffing, safety and management practices, environmental compliance and permits
  • A review of the inputs for financial modelling


We provided two separate due diligence reports:

  • Due Diligence Units 1 & 2 (Wayang Windu Current Geothermal Assets)
  • Due Diligence Units 3 & 4 (Wayang Windu Future Geothermal Assets)

Our due diligence reports identified the resource and technical risks along with the environmental risks with the current station and potential future units and how these risks would be minimised/mitigated.

To ensure EGCO - Thailand was fully aware before investing significantly in Wayang Windu, we also provided recommendations on each major factor influencing the profitability of a geothermal project and detailed the project’s significant issues and shortcomings as well as the positive factors allowing the existing high levels of performance achieved by Units 1 and 2.

The work was completed on time and within budget.


mechanical engineering, electrical engineering, project/program management

due diligence studies, project planning and project management

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