We're investing £155m to support economic growth and decarbonisation in Southampton

Running from July 2025 through to the summer of 2031 and delivered with our contract partner Clancy, this programme of works will significantly enhance the local electricity network’s capacity, resilience, and flexibility.

This will support further economic growth, and the decarbonisation of homes, businesses, and transport.

Designed to improve the reliability of power supplies for people in the city, the upgrades will also support new electricity connections, and the greater uptake of electric vehicles, solar panels, and heat pumps.

In addition to this £155m programme, we're monitoring the ongoing increasing demand for electricity, and looking ahead to other developments that will support Southampton’s future economic growth and decarbonisation. These will be planned to meet forthcoming need, and delivered alongside the necessary forthcoming expansion of National Grid’s own Transmission network, which delivers electricity to local communities like those in Southampton.

The £155m programme in detail

15 schemes are within this £155m package of investment. These encompass upgrades to substations, transformers, underground cable routes, and the construction of what’s known as a Bulk Supply Point. This new site will convert the electricity voltage to the required level for its onward journey to the homes and businesses that are connected to our local distribution system.

Half of these projects will specifically deliver additional network capacity for the Southampton area, while all of them will deliver a local network that’s even more resilient and efficient. The new Bulk Supply Point and the provision of two new high-voltage power circuits will themselves increase network capacity in the Southampton area by around 180MVA by the early 2030s.

The programme has also been carefully designed to protect the network in the face of a changing climate, and to align with Southampton City Council’s wider plans to mitigate the potential impact of flooding. For example, one new substation will sit within an existing site we already operate, but will be elevated to minimise the risk of potential water ingress. The network in the vicinity of this substation is also being upgraded to provide greater network capacity.

SSEN’s Project Director, Neil Hitchcock said:

“Southampton’s a growing area, and demand here for electricity is increasing. This project will support the city’s future growth using cleaner, greener electricity.

“SSEN’s investment in upgrading the network will increase capacity and improve efficiency. In doing this, emissions will also be reduced through the increased uptake of low carbon technologies, supporting our customers on their own decarbonisation journeys.”

Some of the work on this £155m project will involve the replacement of network equipment that’s already in place, through the installation of new underground cables and upgraded, more efficient substations.

Neil continued:

“While this huge investment will deliver for communities in the near term, we’re already looking ahead to further developments that will support the community’s ongoing decarbonisation in coming decades.

“Moreover, the benefits of this £155m project will endure long after these works are completed, through the creation of more skilled jobs and new training opportunities.”

Councillor Sarah Bogle, Southampton City Council’s Cabinet Member for Economic Development said:

“Southampton is a city of opportunity, with ambitious plans for inclusive growth to support local people and businesses and I am pleased with the commitment and enthusiasm demonstrated by SSEN with the investment being made in these vital projects. 

“One of the critical issues we face is having an electricity supply and infrastructure that supports our future growth. Through this investment we’ll see improved resilience and new opportunities for young people delivered alongside the capacity enhancements Southampton needs. 

"I look forward to building on our partnership with SSEN and ensuring that Southampton’s inclusive growth and sustainability goals continue to be supported.”

For more information, updates, and access to community events, please visit SSEN’s Southampton project page: www.ssen.co.uk/southampton