The project is part of a £3.2 billion upgrade to Wales’ electricity transmission network over the next five years, designed to meet rising energy demand and support the shift to cleaner power.
Matthew Cumming, development director at National Grid, said: “As South Wales’ electricity needs continue to grow, we need to upgrade the network to connect new renewable energy, storage and demand.
“Our proposals will help transform a site once associated with coal-fired power generation into infrastructure that supports a cleaner energy future and the region’s continued growth.
“We encourage local people to come along, learn more about the plans and share their views.”
The proposed Gileston substation would be built on land next to National Grid’s existing Aberthaw substations and would replace infrastructure dating back to the 1950s.
The site sits beside the former Aberthaw Power Station, which was once a major coal-fired plant.
The new substations would support connections for renewable energy, battery storage and a data centre, as requested by developers in the region.
National Grid, which owns the electricity transmission network in England and Wales, has a legal duty to facilitate these connections.
The project represents “the next chapter in the area’s energy story,” transforming a site once known for coal-fired power into infrastructure that will help enable a cleaner, more flexible energy system in South Wales.
The investment will also improve network resilience and help prepare for future growth across the region, including in the AI Growth Zone.
The company is encouraging the public to get involved and share their views on the proposals.
A drop-in information event will be held at The Gathering Place in St Athan on Tuesday, October 6, 2026, from 2.30pm to 7pm.
Residents, businesses and community groups will be able to meet the project team, view the proposals, and provide feedback.
For those unable to attend in person, an online webinar will take place on Thursday, October 8.
The project is part of National Grid’s wider plans to modernise Wales’ energy infrastructure and support the national transition to renewable energy sources.
Further details about the Aberthaw substation scheme and public consultation opportunities are available on the National Grid project website.
