We speak quite a bit about the constraints that the UK grid currently faces, but new research from Savills has suggested that the picture isn’t exactly universal.
In fact, according to its analysis, Savills found that there is an apparent surplus of grid capacity at distribution level. Despite that, there’s also a clear mismatch between where capacity exists and where it is needed, which is increasingly dictating the pace and location of new housing, commercial and industrial projects.
Using its Grid IQ platform, developed by Savills Earth, the firm tracked the evolution of available supply capacity in the distribution network from June 2024 to August 2025. Over that period, available capacity at primary substations increased by around 2GW, bringing the total to 39GW. That headline figure has remained broadly flat (within ±5%) over the past two years.
During the same period, demand connection applications rose by 30%, taking the total queue to 29GW – roughly equivalent to the power required to supply 14.5 million homes.
On paper, that means available capacity is about 34% higher than the demand currently in the queue. In practice, Savills warns that the geographic distribution of that headroom is misaligned with development needs, leaving some areas heavily constrained while others retain unused capacity.
Regional disparity between grid availability
It’s no secret that there is a regional disparity when it comes to how much grid capacity is available. It’s become even more acute in recent years as renewable energy infrastructure is built in areas that aren’t exactly demand centres – like the North Sea and Scotland.
The problem is, demand is more likely to grow in existing areas – such as in London and the South East – rather than in those areas with a glut of renewables. That means distribution network operators in those areas need to work harder to ensure there’s grid capacity available for new connections.
One example is in London and the South East, which saw an 11% increase in demand headroom – around 1GW – following revised peak demand calculations by UK Power Networks. That uplift could help ease some of the constraints on housing and mixed-use schemes in the capital and its commuter belt.
Elsewhere, the story is less positive. The Midlands and South West experienced a 14% drop in capacity, a fall linked to a surge in logistics development that has absorbed available power at key substations. Further north, headroom across the B6 Boundary – the critical bottleneck between Scotland’s renewable generation and demand centres in England – fell by 23%, exacerbating constraints on new projects in the region.
Savills argues that these shifts underline the need for developers and investors to engage much earlier with grid data when considering site selection and scheme design, rather than treating connections as a late-stage technical hurdle.
Could TNUoS changes unblock capacity?
From April 2026, rising Transmission Network Use of System (TNUoS) charges could add a new dynamic. Higher charges may prompt some non-residential site owners to reduce their agreed import capacity in order to cut costs, potentially freeing up headroom for new connections.
Savills estimates that more than 210,000 non-residential sites will be affected by the change. Even modest reductions in import capacity across that cohort could have a significant cumulative impact on the availability of capacity in some areas, although the effect is likely to be uneven region by region.
Phil Pearson, Director, Energy, Renewables and Infrastructure, Savills, noted, “The ongoing connections reform and forthcoming TNUoS charge adjustments highlight the need for developers to monitor each part of the network to identify and secure capacity. Developers who understand these changes and incorporate grid readiness into site selection, design, and investment strategies will be best placed to deliver resilient, future-proof projects in an increasingly capacity-constrained market.”
