Client Background

A leading energy developer in the Philippines engaged in a geothermal power plant project required a reliable pipeline system to extract and transport underground hot water (approx. 60°C) for electricity generation. The fluid is corrosive, and the pipeline must withstand high pressure (4 MPa) under continuous operation. Key challenges included corrosion resistance, long-term durability under high temperature and pressure, and ease of installation in rugged geothermal fields.

Requirements

Corrosion-resistant materials suitable for geothermal brine.

Ability to withstand continuous high pressure (4 MPa) and high temperature (60°C+).

High tensile strength and ring stiffness for deep extraction and surface transportation.

Simple, fast installation to reduce project downtime.

Pipe diameters between 140 mm to 250 mm, with compatible fittings.

Enhanced Solution Provided by SIFFO

SIFFO recommended its HDPE Steel-Reinforced Composite Pipes (140–250 mm diameters), along with custom-designed high-pressure electrofusion fittings, to form a complete, leak-proof system for the harsh geothermal environment.

Product & System Features

Advanced Lining Material – Inner layer made of modified high-temperature PERT, capable of continuous operation at up to 70°C, ensuring resistance to thermal degradation and fluid corrosion.

Steel Reinforcement – Spirally wound high-strength steel wire skeleton provides exceptional tensile strength and ring stiffness, enabling the pipe to withstand high extraction pressure (4 MPa+) and external loads.

Corrosion Resistance – The HDPE outer layer and inert PERT inner layer prevent chemical and electrochemical corrosion, ideal for saline and mineral-rich geothermal fluids.

Complete, Leak-Free Connection System – Custom-manufactured high-pressure electrofusion fittings (including elbows, tees, reducers, and flanges) are provided for all connection points. These fittings feature embedded heating wires and are designed to match the pipe's pressure rating and material structure.

Simple Installation –   Connections are made using portable electrofusion welding equipment. The process is largely independent of operator skill, ensuring consistent, high-integrity joints.

Homogeneous Joint –  The fusion process creates a monolithic, leak-proof connection as strong as the pipe itself, critical for maintaining system integrity under 4 MPa pressure.

Corrosion-Resistant at Joints –  The fusion joint eliminates potential leakage points and maintains uniform corrosion resistance throughout the system.

Lightweight & Installation Efficiency – The composite pipe system is lighter than steel alternatives. Combined with the streamlined electrofusion process, it significantly reduces installation time, labor costs, and reliance on heavy equipment.

Project Implementation

Pipes and custom electrofusion fittings were delivered to the geothermal site.

On-site teams achieved rapid, reliable installations using standardized electrofusion welding procedures. The process required minimal preparation and no complex welding expertise.

The entire system, including all fused joints, was successfully hydrostatically tested at 6 MPa and has operated stably at 60–65°C with zero leakage.

Results & Benefits

Reliable, Monolithic System: The electrofusion connections eliminated the weak points typically associated with mechanical joints, ensuring uniform performance under 4 MPa pressure.

Enhanced Integrity & Safety: The leak-proof fused joints are ideal for handling hazardous geothermal fluids, protecting the environment and personnel.

Cost & Time Efficiency: Simplified installation reduced project downtime. Lower maintenance needs further decreased the total cost of ownership.

Long Service Life: The fully integrated, corrosion-resistant system is designed for over 25 years of service in harsh geothermal conditions.

Conclusion

By providing a complete piping solution comprising HDPE steel-reinforced composite pipes and custom high-pressure electrofusion fittings, SIFFO delivered a robust, reliable, and easy-to-install system that perfectly met the project's demanding technical requirements. This case highlights SIFFO's capability to supply not just components, but fully integrated, performance-guaranteed fluid transport systems for critical energy infrastructure.