Rangipo Power Station: Delivering Critical Life-Extension Works

When key equipment at Rangipo Power Station approached the end of its original design life, Edison supported Genesis Energy through a critical multi-year programme to refurbish and extend the life of one of New Zealand's most strategically important renewable generation assets.

Commissioned in 1983, Rangipo Power Station is a critical component of the Tongariro Power Scheme, providing 120 MW of renewable generation to the national grid. After four decades of operation, key plant equipment was approaching the end of its original design life. Genesis Energy initiated a programme of targeted refurbishment and life-extension works to maintain reliability, improve safety, and extend the station's operational life ahead of any future targeted asset replacement projects.

Edison was engaged to provide on-site electrical engineering and project management support across multiple workstreams over a three-year period, helping deliver complex upgrades within a live, underground hydro generation environment.

Challenge

Delivering major plant replacement and refurbishment projects within an underground hydro facility introduced a unique set of technical and operational challenges. The station is a critical asset, meaning outages can be tightly constrained at times, and execution risks within the underground environment must be carefully managed.

Key challenges included:

• Integrating new high-voltage SF6 equipment with legacy infrastructure nearing end of life.
• Managing complex interfaces with Transpower-owned assets within a shared underground SF6 switchroom.
• Coordinating multiple concurrent outage workstreams across projects, maintenance, and contractors.
• Delivering generator refurbishment and high-voltage testing within strict safety and compliance frameworks.
• Maintaining continuity of engineering oversight where client resources were distributed across multiple sites.
• Genesis required experienced, site-based support to provide coordination, technical assurance, and real-time decision-making throughout the programme.

Solution

Edison provided embedded electrical engineering and project support across several critical workstreams, maintaining a consistent, as required, on-site presence throughout planning, outage execution, and recommissioning phases. This presence enabled key Genesis technical staff to be deployed on other project locations within the Genesis generation portfolio.

This included:

• Project coordination and outage planning: Supporting pre-outage preparation, contractor coordination, and alignment across parallel workstreams.
• Interface management: Coordinating works between new and existing plant, including complex GIS replacements and interactions with Transpower infrastructure.
• Electrical engineering oversight: Supporting generator refurbishment works, including inspection, testing, defect management, and return to service.
• Quality assurance and compliance: Ensuring all works met Genesis safety standards and contractual requirements, including management of inspection and test plans and reporting.
• Responsive problem solving: Providing practical, real-time engineering input to manage emerging issues and maintain progress during constrained outage windows.

Edison’s on-site presence enabled early identification of risks and plant issues, consistent communication across stakeholders, and effective coordination of complex activities.

Key Results

Edison’s support and collaboration with key Genesis staff enabled the successful delivery of critical life-extension works at Rangipo Power Station, ensuring the continued performance of this key renewable asset. By combining technical expertise with strong coordination and on-site presence, Edison helped Genesis Energy extend the life of critical infrastructure and maintain reliable renewable generation for New Zealand.

Key outcomes included:

• Extended asset life and improved reliability: Targeted refurbishment reduced operational risk and supported continued generation from a 120 MW renewable asset.
• Successful delivery of complex upgrades: High-voltage GIS circuit breaker replacements and transformer works completed and commissioned within tight outage constraints.
• Efficient outage coordination: Multiple concurrent workstreams delivered safely and effectively within a constrained underground environment.
• Improved safety and compliance: All works completed in line with stringent safety and technical standards.
• Trusted delivery partner: Ongoing engagement across multiple projects reflects Genesis Energy’s confidence in Edison’s ability to support critical infrastructure