Transformer Life Extension: GSU Transformers at Tucurui Dam. Case Study Around Vital Role in Sustainability, Resilience and Reliability.

The modernization of the Tucuruí Hydroelectric Plant, one of Brazil’s largest facilities, provided a unique case study to evaluate two technological pathways: (i) installation of two new generator step-up transformers (GSUs) and (ii) life extension of two legacy Brown Boveri

& Cie units that have operated for approximately four decades. Both solutions were designed with identical ratings of 378 MVA and 13.8/525 kV, ensuring full interchangeability within the infrastructure of the hydro plant. The new GSUs were engineered with a short-circuit strength of 60 GVA, while the refurbished units were upgraded from their original 40 GVA to 60 GVA, representing a significant engineering achievement given design constraints.

This study applies carbon footprint analysis and Life Cycle Assessment (LCA) to both approaches, considering manufacturing processes, raw material sourcing, energy consumption, transportation, installation and use (cradle-to-use). The comparative assessment highlights critical dimensions such as raw material utilization, manufacturing emissions, waste reduction, and operational efficiency, aligned with hydropower sustainability objectives.

Preliminary results indicate that new transformers deliver superior technical performance and reduced electrical losses. However, extending the life of legacy units substantially decreases delivery time, carbon emissions, and resource demand by avoiding the energy and material intensive production of new equipment. The findings underscore the trade-offs between technical optimization and environmental impact, offering a balanced perspective on modernization strategies in large-scale power generation.

The Tucuruí case exemplifies how innovation and sustainability can be reconciled in infrastructure upgrades. Advanced refurbishment techniques, combined with circular economy principles, demonstrate that extending transformer lifespan constitutes a technically viable and environmentally progressive solution. This approach supports reliability, affordability, and sustainability goals simultaneously.

A key factor enabling the implementation of the life-extension alternative was the active engagement of the asset owner, which supported the evaluation of non-conventional modernization strategies aligned with sustainability objectives. By actively promoting the lifeextension alternative, Axia Energia reinforced its commitment to sustainable innovation. Their engagement facilitated project execution and highlighted the importance of stakeholder collaboration in achieving environmentally responsible and technically advanced outcomes.

This leadership sets a benchmark for aligning large-scale infrastructure projects with global sustainability objectives, providing a replicable model for the broader energy sector.