New Britain Geothermal PreFeasibility Study

Objective

Fortescue engaged io consulting to conduct a Pre-Feasibility Study (PFS) for the development of geothermal power in New Britain, Papua New Guinea (PNG). The study aimed to evaluate the technical and economic feasibility of a large-scale geothermal power plant to supply industrial users, primarily for green ammonia production. The objective was to define a cost-effective and scalable development strategy, balancing subsurface uncertainty with commercial viability.

Project Scope

The study focused on four geothermal prospects in the West New Britain province:

1. Pangalu-Talasea – Estimated potential 200-800MW
2. Welcker-Garbuna – Estimated potential 200-500MW
3. Pago-Kasiloli – Estimated potential 100-400MW
4. Walo-Silanga – Estimated potential 100-300MW)

Key activities included:

• Reservoir and well performance analysis to estimate steam productivity and injection requirements.
• Steam Above Ground System (SAGs) network design to optimise pipeline routing and steam transportation.
• Power plant technology assessment to determine the most cost-effective generation system.
• Economic modelling to estimate CAPEX, OPEX, and Levelised Cost of Electricity (LCOE).
• Social and environmental screening to identify permitting challenges and mitigation strategies.
• Risk and opportunity assessment to inform future development decisions.

Findings & Recommendations

Findings

• Geothermal Reservoir Potential & Development Strategy: The estimated total geothermal potential of the four prospects ranges from 600MW to 2,000MW, with a base case of 1,300MW.
• Steam Turbine Size Standardisation: A 60MW turbine size balances economies of scale with development flexibility.
• Power Generation Technology Selection: Different resource types require different power plant technologies. The following configurations were identified as most suitable:
  • Dry Steam for Welcker-Garbuna (steam-dominated)
  • Single Flash for Pangalu-Talasea, Pago-Kasiloli and Walo-Silanga (liquid-dominated)
  • Binary and Combined Cycle technologies were found to be less cost-effective for initial deployment.
• Steam Above Ground System (SAGs) Network Optimisation: Pipeline routing and steam pressure management are critical to minimising energy losses. A centralised power plant reduces infrastructure costs but increases reservoir risk.
• Environmental & Social Considerations: The Welcker-Garbuna and Pangalu-Talasea prospects have the lowest environmental risk but still require extensive stakeholder engagement. Potential emissions of CO₂ and H₂S could impact the project’s green credentials.
• Potential for Mineral Extraction from Geothermal Brines: New Britain’s geothermal brines have high silica concentrations and may contain valuable minerals like lithium and boron.

Recommendations

1. Geothermal Reservoir Potential & Development Strategy: Adopt a phased development approach, prioritising the Pangalu-Talasea and Welcker-Garbuna prospects due to their lower cost and higher steam potential. This strategy minimises subsurface risk while maintaining flexibility for future expansion.
2. Steam Turbine Size Standardisation: Standardise on 60MW steam turbines for initial deployment, ensuring cost-effective procurement and operational efficiency. Larger turbines could be considered if reservoir outcomes are highly positive.
3. Power Generation Technology Selection: Deploy Single Flash technology for liquid-dominated reservoirs and Dry Steam technology for steam-dominated fields. Consider binary as a secondary system to improve energy recovery in later phases.
4. Steam Above Ground System (SAGs) Network Optimisation: A hybrid approach is advised, with centralised power generation for initial phases and distributed generation for future expansions if required. Optimising pipeline design and reducing backpressure can improve overall efficiency.
5. Environmental & Social Considerations: Continue community engagement and permitting efforts early in the project timeline. Investigate emission mitigation strategies, including CO₂ re-injection or mineral extraction.
6. Potential for Mineral Extraction from Geothermal Brines: Conduct further fluid chemistry analysis to determine the feasibility of mineral co-production as an additional revenue stream.