Headroom by Substation

Overview

This page shows individual substation-level network headroom (firm capacity vs. forecast demand) within a chosen DNO licence area — the most detailed view in the headroom family, beneath Headroom & Growth by GSP Area. Colour shows headroom as a continuous scale (green = more headroom, red = constrained); substations with no published firm capacity rating show no colour at all. DNO planning forecasts cover 2025–2030 directly; the pathway dropdown below chooses which NESO regional scenario extends the view from 2031 onwards.

Data sources

• Network headroom (firm capacity vs. forecast demand): each DNO's published Long Term Development Statement (LTDS) — the network planning report every distribution licensee issues annually, giving substation ratings and demand forecasts for 2025–2030.
• Some substations have no firm capacity rating and so no headroom value. A published demand forecast doesn't always come with a matching capacity rating, so headroom % and headroom (MVA) can't be calculated for every substation. This gap is substantial for two DNOs — around a quarter of NGED's and SSEN's substations — while ENW, NPG, SPEN, and UKPN have none. Those substations still appear on the map (switch the metric to Forecast Demand or Firm Capacity to see what data they do have) but show no colour value under Headroom % or Headroom (MVA).
• We extend each substation's 2030 LTDS rating through 2050 using a regional growth multiplier, not a separate substation-level forecast. NESO publishes demand growth for each GSP area under three pathways (Holistic Transition, Electric Engagement, Hydrogen Evolution); we grow every substation in that GSP area by the same factor, relative to its own 2030 LTDS anchor.
• We convert MW to MVA using a fixed 2024/25 power factor, held constant across all years to 2050, for the DNOs that publish demand in MW rather than MVA (UKPN, NGED, and SSEN SHEPD). As electrification shifts the load mix over that horizon, the real power factor will move away from this fixed one — understating or overstating capacity utilisation in the later years shown.
• GSP area attribution has two tiers, and about a fifth of NGED substations fall through both. We resolve each substation's location from each DNO's own published location dataset, then match it to a GSP area by testing which GSP area boundary physically contains that location. Where no location resolves, a fallback matches the substation's own published GSP area name against a name-mapping lookup instead. Some substations resolve to neither: around 20% for NGED, 10% for SPEN, 9% for SSEN, and 4% for NPG, with none for ENW or UKPN. These are out-of-area classifications and cases where a DNO's GSP group straddles a NESO licence-area boundary, pending review by a domain expert with access to NESO's own boundary data. Those substations still appear on the map and carry a licence area, but show no GSP area in the tooltip.
• We read licence area directly from the LTDS source a substation was published in, so it's complete for every substation regardless of the GSP area gap above.
• Licence areas are shown individually rather than rolled up by DNO, because some DNOs (e.g. SSEN's SEPD and SHEPD) cover spatially distinct, non-contiguous areas.