To meet a large increase in grid connections, AECOM partnered with Transpower in New Zealand to co‑develop a standardised, portable digital substation platform, replacing kilometres of copper with a fibre‑optic network and enabling off‑site pre‑commissioning. The result: a faster, safer, more scalable way to deliver substations for New Zealand’s energy transition.
Designing digital substations for New Zealand
New Zealand’s renewable build‑out is accelerating, and the transmission grid must keep pace. Traditional substation delivery often stretches across years, constrained by analogue control systems, dense copper cabling, and a construction sequence that pushes testing to the very end.
Working shoulder‑to‑shoulder with Transpower over several years, we helped take digital substation concepts from feasibility to first implementations. By digitising data at the device and moving it via a site‑wide fibre‑optic network into a smaller, standardised, portable control building, we created a platform designed for speed, repeatability and safety, without losing the familiarity that operations and field teams rely on.
Co‑developing a standardised platform
We supported Transpower from initial feasibility, assessing whether digital substations had matured enough for adoption, through to concept development, standards alignment and design. Our team led most of the physical hardware design, contributed to software design parameters and developed the portable building concept to house the protection and control systems.
To derisk integration, we designed a test lab at Transpower House so that multi‑vendor devices could be type‑tested and verified before field deployment. Throughout, we produced detailed three-dimensional models of cabinetry, equipment and the building, helping internal stakeholders visualise the solution, accelerate decisions and maintain alignment as the concept evolved.
Designed for familiarity and change
With a near “clean slate”, the challenge wasn’t only innovation, it was adoption. We worked with Transpower to ensure the solution preserved operational familiarity while introducing step‑change improvements behind the scenes. The platform is intentionally standardised: a consistent control building and equipment arrangement configured to each site, rather than redesigned from scratch. That standardisation reduces design effort, simplifies testing and shortens commissioning, critical advantages when scaling delivery across multiple projects.
Speed to energisation
At Ōhangai (South Taranaki), a new site supporting Fonterra as part of its investment into electrification projects, the first portable control building arrived on site in mid‑January 2026, with commissioning targeted for June. That approximately 18‑month go‑to‑energisation timeline would be unheard of under traditional approaches. Off‑site pre‑commissioning is the answer: the building can be integrated and tested at a depot, then brought to the site ready to connect.
Safety, productivity and environmental benefits
By moving testing off‑site, technicians spend less time travelling and fewer days exposed to site conditions. The shift from copper to fibre reduces the number of terminations and simplifies layouts, contributing to cleaner, safer work environments. The smaller control building footprint and significantly lower copper use improve material efficiency. The team also explored lower‑impact options (such as recycled-plastic foundations), demonstrating a continuous-improvement mindset even when alternatives aren’t adopted.
Built to scale
Because the platform is standardised and configured rather than bespoke, it is inherently repeatable. That makes resourcing more predictable, compresses design cycles and streamlines commissioning steps, advantages that compound as the pipeline grows. Following Ōhangai, we’re progressing detailed design for Puna Awa (South Island), extending the approach to a second deployment.