SSEN places first modular substation orders

In Brief

SSEN Transmission has placed the first project orders under modular substation frameworks awarded to Hitachi Energy and GE Vernova in May.

Fifteen 132kV/33kV modules representing more than 1GW of renewable generation are due to be ordered by the end of 2026.

Much of the assembly, wiring and testing will take place offsite before installation and commissioning.

Procurement documents show the framework also covers installation and cold commissioning, with a 132kV modular substation for Blarghour awarded in July.

SSEN plans to use the approach across the majority of its customer-connection portfolio, with first energisations expected from autumn 2028.

In Review

SSEN Transmission has started placing project orders under its new modular substation frameworks, putting a standardised approach to smaller grid connections into commercial deployment.

The transmission operator expects to order 15 modules representing more than 1GW of renewable generation by the end of 2026, with further orders due to follow.

The 132kV and 33kV substations are intended primarily for smaller customer connections, including individual wind farms and other renewable generators. Rather than developing each substation as a largely bespoke site build, the approach allows much of the assembly, wiring and testing to be completed in controlled factory environments before equipment is transported to site.

That shifts a meaningful portion of substation delivery away from the construction site. Procurement documents show the framework covers not only supply and delivery, but also installation and cold commissioning – the testing carried out before equipment is energised.

The first call-offs are already starting to appear. A contract awarded to UK Grid Solutions Limited in July covers the supply, delivery, installation and cold commissioning of a 132kV modular substation for Blarghour in Argyll.

SSEN awarded the wider frameworks to Hitachi Energy and GE Vernova in May following a year-long competitive tender process. At the time, it said the modular approach would be rolled out across a large portion of its customer-connection projects; it now says the programme is expected to cover the majority of the portfolio.

SSEN argues that completing more work in factories will shorten construction programmes, reduce time spent on site and allow smaller site footprints, while giving project teams a standardised design that can be repeated across multiple connections.

Those benefits have not yet been quantified publicly, however. SSEN has not disclosed how much overall construction or commissioning time it expects the modular approach to save compared with conventional bespoke delivery, or the scale of any expected cost reduction.

That will become clearer as the first projects move through installation and commissioning. Initial energisations are scheduled from autumn 2028.