System architecture
The physical network gets most of the attention, but the data layer underneath it determines whether the system can be planned, operated, and settled. This page covers the technology stack, the Common Information Model, and the data flows that hold the GB energy system together.
The GB energy system runs on a five-layer digital stack. Each layer depends on the one below it. Understanding this stack is essential for understanding why data problems cascade upward into operational and market failures.
The Common Information Model (CIM), defined by IEC 61968 and IEC 61970, is the standard data model for the electricity industry. It provides a shared vocabulary for describing the network, its assets, and their relationships.
CIM provides a common vocabulary for describing the electricity network: generators, transformers, substations, circuits, load points, and how they connect. Instead of every organisation inventing its own data model, CIM offers a shared structure that software systems can read and write.
Without a common data model, every data exchange between organisations requires custom integration work. CIM enables different software systems to exchange network data without building bespoke translators for every pair of systems. This reduces cost, error, and delay.
Adoption is partial. NESO uses CIM for some data exchange. DNOs have varying levels of adoption, often depending on when their systems were last upgraded. Full CIM compliance across the GB system is a long-term goal, not a current reality.
Practical impact: without CIM, connecting a new solar farm requires manual data translation between NESO, the transmission owner, and the DNO. Each organisation describes the same physical assets using different data structures, different field names, and different units. CIM is meant to eliminate that friction.
| Organisation | Data model | Adoption level | Key gap | Migration timeline |
|---|---|---|---|---|
| NESO | IEC CIM (61970/61968) | Partial - transmission model | Distribution data not in CIM | 2025-2028 |
| DNOs | Proprietary + GIS | Low - legacy systems | No common schema across 6 DNO groups | 2026-2030 |
| Elexon | BSC data model | Medium - settlement only | Not linked to network model | Post-MHHS |
| DCC | Smart meter hub | High for metering | No integration with CIM | Under review |
Three primary data flows run through the GB energy system. Each carries different data, serves different purposes, and follows a different path.
Smart meters send consumption readings to the DCC (Data Communications Company), which routes them to energy suppliers for billing and to Elexon for settlement. Over 34 million smart meters now generate half-hourly reads. This data underpins billing, settlement, and demand forecasting across the retail market.
SCADA sensors across the network feed real-time voltage, frequency, and power flow data to the NESO control room. Thousands of sensors report at intervals measured in seconds. This data drives dispatch decisions, frequency response, and system balancing. Without it, the control room is blind.
Trading platforms and settlement systems feed data to Elexon's BMRS (Balancing Mechanism Reporting Service). Wholesale prices, generation by fuel type, interconnector flows, and system warnings are all published openly. This data enables market participants and researchers to track system performance in near real time.
Three reforms are reshaping the data infrastructure of the GB energy system. Each addresses a different gap, but all share the same premise: the current data layer is not fit for a decarbonised, distributed energy system.
Market-wide Half-Hourly Settlement brings granular metering data into the settlement process for the first time. Instead of profiling estimated consumption across broad customer classes, MHHS uses actual half-hourly reads from smart meters. This enables time-of-use tariffs, sharper demand signals, and the flexibility markets that a high-renewables system needs.
A centralised data sharing platform with business rules now finalised. The Hub will consolidate fragmented data sources and provide standardised access for authorised parties. It is designed to enable third-party innovation in energy services, from EV charging optimisation to community energy schemes, without each innovator negotiating bilateral data agreements.
NESO and several DNOs are building digital twins of the network: virtual models that mirror the physical system in near real time. These enable scenario modelling (what happens if we connect 500 MW of solar here?), predictive maintenance (which transformers are likely to fail?), and better operational planning across the transmission-distribution boundary.
Supervisory Control and Data Acquisition. SCADA is the system that collects real-time data from sensors across the electricity network and allows operators to monitor and control equipment remotely. Sensors at substations, generators, and interconnection points report voltage, current, frequency, and switch status to a central control room. Operators can then issue commands back through the same system: opening circuit breakers, adjusting transformer taps, or curtailing generation. SCADA is critical for grid stability. Without it, the control room cannot see or act on what is happening across the network.
The Data Communications Company operates the smart meter communications infrastructure in Great Britain. It connects over 34 million smart meters to energy suppliers and network operators through a secure wide-area network. The DCC does not read the meters directly; it provides the communications backbone that allows authorised parties (suppliers, DNOs, NESO) to request and receive meter data. It is independent of any single supplier, which was a deliberate design choice to prevent any one company from controlling the metering data pipeline.
Digital capability now sits alongside physical reinforcement as a delivery dependency for the transition. Planning, settlement, flexibility, and network visibility all depend on data quality, interoperability, and timeliness. That is why reforms such as MHHS, CIM-based data exchange, and wider digitalisation programmes matter beyond the IT function.
Interoperability remains the main implementation task because operators, suppliers, and code bodies still rely on different legacy systems and data models. Common standards such as CIM help create a shared structure, but rollout requires system upgrades, governance, testing, and change management across multiple organisations at once.
Last reviewed: 17 March 2026
This page covers the digital infrastructure and data standards that underpin the GB energy system. Content is drawn from published standards, regulatory documents, and operator reports.
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