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    Dinorwig Power Station, Gwynedd, Wales, UK

    GRP Access Structures

    Project Overview

    With a reputation for excellence in both Fabrication build quality and customer service, we have provided multiple high-level switchgear maintenance platforms with hoop ladder access to the refurbished busbar galleries at this hydroelectric power station to help ensure Dinorwig’s reliability and availability as a power generation station for the National Grid for decades to come. The cost-effective, practical and safe platforms are constructed from our market-leading d2 Dura Profile, Dura Grating and Dura Handrailing components. Heavy duty, non-conductive, non-corrosive and chemically resistant, they provide a lightweight and durable alternative to metal.

    Equipment upgrades to ensure fitness for the future.

    Owned and operated by First Hydro Company, a Joint Venture 75% owned by Engie, Dinorwig Power Station is a pumped-storage hydroelectric plant located deep inside the Elidir Fawr mountain on the boundary of the Snowdonia National Park. When it was fully commissioned in 1984, it was regarded as one of the UK’s most imaginative engineering and environmental projects. As experts in GRP Fabrications, Dura Composites have so far supplied 27 high-level switchgear maintenance platforms including hooped ladders to facilitate maintenance access for the high voltage equipment and to enhance personnel safety.

    Dinorwig comprises upper and lower reservoirs and an underground powerhouse which convert kinetic energy into electricity to act as a critical backup to support the National Grid when demand for electricity gets very high. The power station uses generators with a terminal voltage rating of 18kV which are protected against short-circuit faults by six generator circuit-breakers (GCBs).

    As part of an ongoing framework agreement contract, global technology leaders Hitachi Energy are replacing the GCBs with updated equipment which are expected to be a source of significant operational savings, thanks to their longer maintenance intervals.

    Each of Dinorwig’s six GCB units is made up of three individual phases that are housed inside busbar galleries deep inside the mountain. To enable the upgrading of the GCBs, all equipment in each busbar gallery is dismantled and removed, and new lighting installed. The newer equipment is significantly smaller and therefore layout changes to each gallery are being made to improve the overall footprint and operational performance of the space.

    To facilitate the smooth operation and maintenance of the new switchgear equipment, Hitachi Energy selected Dura Composites as its GRP Fabrication partner. The d2 Dura Grating flooring components that the access structures are fabricated from have been rigorously anti-slip tested and maintain 95% of their slip resistance even after 1 million footfalls. Uniquely in the market, all our Dura Profile components meet or exceed the E23 grade performance requirement of the BS EN 13706 standard, providing greater strength and consistent quality.


    Hitachi Energy

    End Client

    First Hydro Company


    Access Structures


    Specialist Cutting
    Fabrication & Build
    Design & Engineering

    A true design and engineering collaboration

    The Dura Composites and Hitachi design, management, and engineering teams collaborated extensively on this project to deliver a fantastic end result that exceeded the client’s expectations. During the initial stages of the project, the Dura Composites Design & Engineering teams collaborated closely with Hitachi Senior Engineer Service Solutions, based in Switzerland, to comprehensively develop the project’s design brief. Leveraging 3D models of the busbar galleries provided by Hitachi Energy, we established a component library aimed at promoting design standardisation throughout all project facets.

    LL55 4TY

    Our Specialists

    Our in-house Design and Engineering capabilities help you adapt to specific challenges in complex projects, using the most sustainable composite solutions available. Here are some of the team members you can call on.