Hitachi Energy deploys Nynas circular Transformer oil

The pioneering use of NYTRO® RR 900X, a fully circular 100% re-refined transformer oil, in a critical power transformer at Hitachi Energy’s power transformers factory in Cordoba, Spain, demonstrates its technical equivalence to virgin oils and highlights its potential for reducing the carbon footprint of transformers.

Transformer oil, Hitachi Energy

The first retro fill with NYTRO RR 900X was just performed on a critical 117 MVA shell-type test transformer at Hitachi Energy’s Córdoba factory, a special unit used for precise voltage regulation in a high voltage testing laboratory. Electrical and thermal tests have just been successfully concluded, proving the performance of the transformer remains the same as in the case of operating with new virgin mineral oil.   

NYTRO RR 900X is produced by re-refining used transformer oils across large-scale hydrotreaters – similarly to virgin oil production and in the same refinery – complying fully with IEC 60296:2020 standards for mineral insulating oils. This re-refined oil consists of over 99% recycled content, with an added synthetic inhibitor. The oil is sourced from used transformer oil collected from decommissioned or end-of-life transformers, processed in a dedicated refinery using catalytic hydrogenation, and kept segregated throughout logistics to maintain quality and traceability.   

"Reusing end-of-life transformer oil can be a powerful driver for advancing circularity and decarbonization across the transformer value chain. Adopting NYTRO RR 900X is a key step in our commitment to circularity and decarbonisation, demonstrating that innovation-driven sustainability and operational excellence truly go hand in hand,” says Rafael Llamuza, Global Product Manager for Large Power Transformers and Shell Transformers, Business Unit Transformers, Hitachi Energy.  

“NYTRO RR 900X matches the technical performance of virgin super-grade oils in key areas such as oxidation stability, material compatibility, and ageing behavior. At the same time, it offers a reduction in carbon intensity of oil production. As a drop-in solution, it requires no design modifications to transformers,” says Simon Day, VP Sales & Marketing at Nynas.   

Life cycle assessments indicate that using NYTRO RR 900X can reduce the cradle-to-gate global warming potential (GWP) of transformers by up to 8%. NYTRO RR 900X also offers a genuine circularity solution for the transformer industry – diverting used transformer oils from downcycling and incineration, while reducing reliance on virgin minerals for new transformers. 

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