IN Brief:
- National Grid’s Little Horsted substation is now operational, adding around 0.5 GW of capacity to the transmission network.
- The East Sussex site supports UK Power Networks’ adjacent distribution infrastructure and future electricity demand in the South East.
- The project forms part of a wider transmission investment programme covering reinforcement, resilience, and future capacity requirements.
National Grid has brought its Little Horsted substation into operation, adding around 0.5 GW of capacity to the transmission network in the South East.
The new substation is located on the existing overhead line route between Bolney and Ninfield and has been designed to strengthen regional transmission capacity. National Grid has said the additional capacity is equivalent to the electricity needs of approximately 480,000 homes.
The project also supports UK Power Networks, the local distribution network operator, as it completes adjacent substation infrastructure to provide additional capacity for customers in the area. That distribution work will support future demand growth, including new connections, as electrification increases pressure on local networks.
Little Horsted was delivered over a two-year construction period. The programme included the removal of around 65,000 cubic metres of earth to level the site, alongside the transport and installation of two supergrid transformers, each weighing 178 tonnes. Those transformers were moved 27 miles from Shoreham Port in Brighton to the substation site in October 2024.
The project sits within a broader programme of investment across the South East transmission network. National Grid has outlined planned investment of £2.7 billion between 2026 and 2031 to maintain, upgrade, and futureproof the regional network. The energisation of Little Horsted follows other reinforcement activity in the area, including refurbishment work on the overhead transmission route between Lovedean and Bolney.
The operational value of the substation lies in the interface between transmission capacity and local distribution headroom. The UK’s electricity system is increasingly constrained by the ability to move power to demand centres and release capacity at the right voltage level. Transmission upgrades create regional capacity, but that capacity must align with distribution networks, grid supply points, substations, and connection processes.
That coordination is becoming more difficult as demand grows from housing, commercial developments, data centres, electric vehicle charging, industrial electrification, and heat electrification. Local networks must reinforce to meet higher peak loads, while transmission operators must ensure enough capacity exists upstream. Grid supply points are becoming strategic infrastructure assets rather than routine network upgrades.
The project also shows the practical delivery demands behind major substation construction. Transformer logistics, site preparation, ecology works, overhead line interfaces, and staged commissioning can carry long programme lead times. Those delivery constraints now influence the pace of wider electrification, particularly in regions where demand growth is running ahead of historic network assumptions.
National Grid delivered a record year for electricity connections in 2025, including 2.4 GW of new generation capacity connected to the transmission network and around 0.5 GW of demand capacity. Little Horsted adds another completed asset to that build-out while underlining the scale of work still required across the transmission and distribution boundary.
As more local demand connects, the ability to coordinate substation delivery, transformer procurement, route reinforcement, and distribution upgrades will determine how quickly new capacity becomes usable. Little Horsted is now operational, with its wider value set by the connections and local network capacity it enables over the next several years.