SSEN Transmission is introducing a standardised modular substation approach that shifts most assembly, wiring and testing into controlled factory settings before installation and commissioning on site.

Designed for 132kV and 33kV applications, the units are tailored to smaller-scale grid connections, such as individual wind farms and other renewable generation. A video overview accompanies the rollout, which will cover a large share of customer connection projects, with initial energisations expected from autumn 2028.

Building in factory environments enables a repeatable design delivered under safer and cleaner conditions. The approach reduces time on site, shrinks the physical footprint, and lowers costs and community disruption, while continuing to meet stringent safety, quality and reliability standards for critical electricity infrastructure.

After a year-long competitive tender, SSEN Transmission has awarded a major framework agreement to Hitachi Energy UK Limited and GE Vernova to deliver the modular substations.

Rob McDonald, Managing Director of SSEN Transmission, said: "Modular substations represent a revolutionary change in how we deliver customer connections, and SSEN Transmission is at the forefront of rolling this technology out across our network.

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"By doing more of the work off‑site, we can improve safety, shorten construction times and significantly reduce the environmental impact of construction, including smaller site footprints and less disruption for local communities.

"Working collaboratively with our supply chain is central to that approach, and we're actively exploring opportunities that could help support skilled jobs and build technical expertise here in Scotland."

The programme forms part of SSEN Transmission's wider drive to innovate and modernise grid delivery, enabling connections for clean, home-grown power and supporting national clean power and energy security goals.

Markus Heimbach, CEO, High Voltage Products business unit, from Hitachi Energy UK Ltd, said: "In today's environment, critical infrastructure has to do more than perform, it has to endure. The Integrated GIS Assembly is designed with that reality in mind.

"By enclosing EconiQ® gas-insulated switchgear (GIS) within a robust, containerised structure, the IGA protects vital assets from the elements, from interference, and from deliberate damage, while maintaining exceptional reliability. EconiQ SF₆-free technology is as reliable and scalable as the conventional solution and delivers the lowest carbon footprint. It allows substations to be delivered as complete, tested systems, ready to operate safely and securely.

"This approach gives network operators greater resilience, faster recovery and confidence that their infrastructure can continue to serve communities even during periods of disruption and uncertainty."

Clar Collins, Executive Managing Director North South Europe Region, Grid Systems Integration at GE Vernova, said: "We're honoured to have been chosen by SSEN Transmission for this important modular substation programme. By combining modular delivery with GE Vernova's g³ technology, part of our GRiDEA™ SF₆ free solution portfolio, this programme is designed to provide faster, lower-impact renewable grid connections, with more of the work completed off site before installation, while supporting cleaner energy.

"We look forward to working in close collaboration with SSEN Transmission to help deliver sustainable and reliable grid infrastructure that supports Scotland's renewable energy ambitions and strengthens energy security,"