Cross-cutting
See the systems behind the system. This route explains how control rooms, settlement, smart metering, and data standards work together so you can understand why energy operations increasingly depend on software quality as much as physical assets.
Start with the stack and the live infrastructure map, then move into MHHS, public APIs, metering, and governance so you can place each system in the right operational context.
The top of the stack. Public APIs from Elexon, NESO, and the Carbon Intensity team provide near-real-time access to generation, demand, pricing, and carbon data. Anyone can query these for free. The Elexon BMRS API alone publishes over 150 different data feeds.
Settlement calculates how much each supplier owes based on actual consumption versus contracted positions. MHHS will move everything to actual half-hourly settlement, requiring a complete rebuild of the settlement infrastructure. Settlement runs progress through Initial, SF, RF, DF, and Final stages.
Data from millions of meters is collected, validated, and aggregated. Data Collectors retrieve readings. Data Aggregators aggregate by supplier and Grid Supply Point. Under MHHS, these roles are being consolidated into new Smart and Advanced Data Services. Around 20 registered agents process ~1.4 billion readings per day.
The DCC operates the smart metering communication network. SMETS2 meters connect via cellular networks (urban, via Telefonica) and long-range radio (rural, via Arqiva). Data is encrypted end-to-end with each device having its own security credentials. The HAN protocol uses Zigbee / DLMS-COSEM.
At the bottom of the commercial stack sit the physical meters. A smart electricity meter records consumption in half-hourly intervals and communicates readings automatically via the DCC network. The gas meter usually sends readings to the electricity meter via Zigbee, which relays them to the DCC. Over 40 million installed, with the current standard being SMETS2.
Below the commercial metering layer sits the operational technology that network companies use to monitor and control the physical grid. SCADA systems, RTUs, intelligent electronic devices at substations, and increasingly IoT sensors on low-voltage networks. Governed by NIS Regulations with air-gapped security. Protocols include IEC 61850, DNP3, and Modbus.
NESO and network control room systems monitor state, dispatch flexibility, and manage outages and constraints.
Elexon and associated market systems convert metered and contractual positions into imbalance and settlement outcomes.
Meters, DCC communications, and supplier data flows determine whether consumption is visible accurately and in time.
CIM, governance processes, and data quality frameworks make cross-organisation exchange workable at scale.
MHHS is the plumbing change that makes a smarter retail and flexibility market credible. Without it, the system cannot price actual consumption patterns well enough.
Elexon reported on 16 February 2026 that more than two million meters had already transitioned to MHHS. The current milestone timetable points to around 80% migration by October 2026, migration completion by 7 May 2027, and programme cutover by 2 July 2027.
GB energy institutions publish several widely used public APIs and open data services. That matters because they make scrutiny, research, and software development much easier.
Operational and settlement data for the electricity market. Over 150 data feeds updated in near-real-time.
Public live and forecast carbon intensity feeds. National and regional, with grams of CO2 per kWh and generation mix.
System-level data including demand forecasts, wind forecasts, frequency data, and constraint information.
National smart metering communications context and programme information.
Smart meters matter because they turn customer consumption from a billing estimate into an operational and settlement signal.
million meters
Smart and advanced meters in operation in homes and small businesses in the latest official DESNZ quarterly publication.
million+ in smart mode
Meters operating in smart mode in the same DESNZ release. The next official quarterly update was not yet published at review time.
The difference is not just meter age. It is whether the communications and interoperability model supports switching, authorised access, and durable system integration.
Poor interval data weakens settlement, distorts tariff design, and reduces confidence in demand flexibility. Metering is not a side system. It is one of the foundations of the market model.
First-generation smart meters (SMETS1) were designed before the central communications infrastructure was ready. Each supplier built its own proprietary connection, which meant that if you switched supplier, your smart meter would go dumb and revert to estimated readings. SMETS2 meters connect through the DCC's central network and work regardless of which supplier you are with. The DCC has been enrolling SMETS1 meters onto its network to fix the problem, but the process has been slow and some older meters will never be fully compatible.
As the system becomes more digital, permissioning, standards, cybersecurity, and interoperability become operational issues rather than background administration.
The energy system needs data sharing, but not unrestricted sharing. Roles and permissions matter because these systems sit close to critical national infrastructure.
Common models such as CIM matter because they reduce translation overhead between market and network tools owned by different organisations.
Digital dependence makes resilience planning, vendor control, and cyber hygiene part of operational reliability rather than a separate IT conversation.
Last reviewed: 17 March 2026
The route keeps the React digital infrastructure component but now anchors the page shell to current first-party material on MHHS, smart metering, NESO data services, DCC, and Ofgem's digitalisation governance work.
Next domain
Continue into the gas network, where physical infrastructure and market structure create a different set of operational challenges.