Enabling critical energy infrastructure at international scale

NG Bailey is delivering mechanical, electrical and public health infrastructure for a major energy interconnection project, supporting the development of a large-scale HVDC converter station forming part of a cross-border electricity link between the UK and mainland Europe.

The wider project spans approximately 725km of subsea and underground HVDC cabling and provides 1.4GW of bi-directional power capacity, supported by £2.4 billion of private investment. Once operational, the interconnector will enhance energy market resilience, enable the exchange of renewable energy between countries and is expected to reduce carbon emissions by approximately 13 million tonnes over a 25-year period.

Within this context, the converter station represents a critical piece of infrastructure, requiring the integration of complex building services systems to support both operational plant and the wider facility environment.

Delivering integrated building services within a high-voltage environment

The scope includes the installation and integration of a wide range of mechanical, electrical and public health systems to support both the converter hall and associated control buildings. Mechanical systems include approximately 20 air handling units, ventilation and exhaust systems serving the converter hall and GIS areas, general ventilation systems incorporating supply, extract and battery ventilation, and a VRF system within control buildings.

Additional systems include gaseous fire protection, building management systems (BMS), and public health installations comprising sanitaryware, hot water systems and distribution pipework from incoming mains through to potable water points.

Electrical works include the installation of LV switchboards, internal and external lighting systems, small power, and extensive containment systems at both low and high level. The scope also incorporates sub-main distribution, final circuits, fire alarm systems, CCTV, access control, and voice and data infrastructure, all coordinated within a highly serviced and technically demanding environment. Raised access floors and ceiling systems within control buildings further support the integration and accessibility of services.

The density and complexity of systems require a coordinated, design-led approach to ensure alignment between services, structural constraints and specialist equipment interfaces.

Driving programme certainty, safety and quality through controlled delivery

Delivery is underpinned by a structured approach focused on safety, quality and programme performance, aligned to the requirements of critical national infrastructure. Works are being delivered with a clear focus on achieving zero accidents, zero defects and adherence to agreed timescales, while maintaining strong collaboration with the wider project team.

The complexity of the environment requires careful sequencing of works, coordination across multiple disciplines and strict compliance with safety and operational standards. Advanced monitoring technologies, including fibre-optic sensing for real-time temperature and acoustic monitoring, form part of the wider infrastructure, supporting long-term reliability and operational performance.

A consistent and controlled delivery approach ensures that systems are installed, tested and commissioned in line with technical specifications, reducing risk and supporting a predictable programme outcome.

Supporting long-term performance of critical energy infrastructure

The completed infrastructure will support the long-term operation of a strategically important energy asset, enabling efficient and reliable power transfer between international networks.

By delivering coordinated, high-quality MEP systems within a complex HVDC environment, the project contributes to improved energy security, greater integration of renewable energy and enhanced resilience across the electricity network.