The Long-Term Development Statement (LTDS) provides essential information to assist current and prospective users of National Grid Electricity Distribution’s (NGED) network in identifying and assessing opportunities for new or additional use of our distribution system. More information can be found at National Grid – Long Term Development Statement.

The LTDS model in Common Information Model (CIM) contains data relating to each of NGED’s four licence areas, covering the Extra High Voltage (EHV) systems (132kV, 66kV, and 33kV) down to 11kV at primary substations. This dataset represents the first stage in NGED’s transition to publishing the LTDS in CIM format, supporting Ofgem’s LTDS Reform to improve transparency and interoperability across GB networks. In time, it is expected to supersede the LTDS Tabular Model.

Scope of Current Release

In line with Ofgem’s phased implementation of grid modelling requirements, this initial release provides only the Equipment (EQ) profile, which describes the physical network assets and their connectivity. Future phases will expand the dataset to include additional profiles such as:

• Short Circuit (SC) data

• Geographical Location (GL) data

• Steady State Hypothesis (SSH) and other situation modelling profiles

• Topology (TP) and State Variables (SV) for solution modelling

These enhancements will be delivered in accordance with the timelines set out in Ofgem’s updated LTDS direction and Grid Modelling Guidelines.

Purpose and Benefits

Publishing LTDS data in CIM format ensures:

• Machine-readable, standardised network models for improved interoperability

• Greater visibility of network characteristics for developers, flexibility providers, and other stakeholders

• Support for advanced planning tools and digitalisation initiatives across the energy sector

This dataset is intended for use by parties seeking to connect to NGED’s network or develop solutions that require detailed network information. It is provided under NGED’s licence obligations and Ofgem’s Form of Statement requirements.