Half-hourly metering and commercial solar settlement
Modern UK commercial solar systems operate on half-hourly settled supplies — measuring consumption and export in 48 daily blocks. Half-hourly metering is required for SEG, time-of-use tariffs, and most material commercial energy supply contracts. Here's how the metering works and what to verify before commissioning.
What half-hourly settlement means
Under the UK electricity settlement framework, every supply point is allocated to one of several 'profile classes' or to half-hourly settlement (HHS). Profile classes use estimated consumption patterns based on historical averages; HHS uses actual measured consumption in 48 daily blocks.
Half-hourly settlement is mandatory for:
- All sites with an Maximum Demand greater than 100kVA - All sites on the Capacity Market or Demand Side Response programmes - All sites with Smart Export Guarantee on commercial supplies - All sites on time-of-use commercial tariffs
Under the Market-wide Half-Hourly Settlement (MHHS) programme, all UK sites are migrating to HHS by 2026-2027. Smaller commercial sites currently on profile classes 5-8 will move to HHS over the next 18 months.
For commercial solar, HHS is essential — your SEG supplier needs to know exactly when you exported and how much.
The MPAN and what it tells you
The Metering Point Administration Number (MPAN) is the unique 21-digit identifier for your supply point. Format:
- First 2 digits (Profile Class): 01-08 for non-HHS; 00 for HHS - Digits 3-4 (Meter Time Switch Class): Tariff complexity code - Digits 5-6 (Line Loss Factor): Geographic / voltage code - Digit 7 (Distributor): Indicates DNO region - Digits 8-21 (Unique core): Supply-specific identifier
Key facts:
- HHS sites have MPAN starting 00 - Half-hourly meter installations require advance arrangement with the supplier - MPAN format is identical across DNO regions; the supplier maps to the DNO via the distributor code - Multiple MPANs can be associated with one site (e.g. landlord supply + sub-tenant supply)
For SEG applications, you need:
- Your MPAN (starts with 00 if already HHS-settled) - Your import supplier and account number - Your export supplier (can be different from import) - Smart meter serial number - DNO connection agreement reference
Smart meters and SMETS2
The current UK smart meter specification is SMETS2 (Smart Metering Equipment Technical Specification 2). Earlier SMETS1 meters were largely upgraded between 2020-2024 via the Data Communications Company (DCC) network migration.
For commercial solar:
- SMETS2 smart meter required for HHS settlement - Capable of bi-directional measurement (import and export) - Communications via DCC allowing supplier switching without meter replacement - Data feed to MOP (Meter Operator) for half-hourly settlement
Sites with older meters need replacement before solar commissioning. The cost is typically borne by the supplier (no charge to customer) but the timeline can be 4-8 weeks.
For smaller commercial sites without smart meters, the supplier's installation process is:
1. Request smart meter installation via supplier portal 2. Site survey and appointment (2-4 weeks) 3. Installation visit (1-2 hours) 4. Commissioning and DCC enrolment (1-2 weeks) 5. First HHS-settled bill on next supply month
Time-of-use tariffs and solar economics
Half-hourly metering enables time-of-use commercial tariffs — paying different rates by time of day. For solar generation sites:
- Day-time rates (typically 7am-10pm): Used when solar covers load - Off-peak rates (typically 10pm-7am): Used when grid supplies load (typically lower) - Peak rates (winter 4-7pm in some tariffs): Highest grid rate
For a typical commercial site:
- Daytime import rate: £0.24-£0.30/kWh - Off-peak rate: £0.10-£0.16/kWh - Average blended rate: £0.22-£0.27/kWh
Solar self-consumption mostly displaces daytime import (the highest rate) — so a time-of-use commercial tariff makes solar economics slightly stronger. Battery storage paired with solar can capture additional value by charging from off-peak grid and discharging during peak.
Octopus Energy, EDF Business, SmartestEnergy, Bryt Energy and others offer time-of-use commercial tariffs. Compare options when negotiating supply contracts.
Settlement period and dispute resolution
Settlement periods in UK electricity:
- R1 to R3 reconciliation: Initial readings, typically settled within 7 weeks of consumption - RF (Reconciliation Final): Final settlement, within 14 months - R2 (Late Settled): Settled after RF — used for dispute resolution
For solar generation sites, half-hourly export data flows from your meter to:
1. DCC (Data Communications Company) 2. DCC to MOP (Meter Operator) 3. MOP to your SEG supplier 4. SEG supplier credits your account
Disputes typically arise when:
- Smart meter data is incomplete or interrupted - DCC enrolment is delayed - Switching to a new SEG supplier takes longer than agreed - MPAN mismatches between systems
Resolution: contact your SEG supplier first; escalate to MOP if data dispute; escalate to Ofgem Consumer Code if unresolved.
Half-hourly metering and commercial solar settlement · FAQs
Do I need a smart meter for commercial solar?
Yes for SEG payments. SMETS2 smart meter required for half-hourly settlement and bi-directional measurement.
Who installs the smart meter?
Your import electricity supplier installs it free of charge (typically). Lead time 4-8 weeks from request to commissioning.
Can I have different suppliers for import and export?
Yes. SEG and import contracts are separate. Many businesses take import from a competitive supplier and SEG from Octopus Outgoing Fixed or Good Energy Solar Savings.
What is the MPAN?
21-digit identifier for your supply point. Found on your electricity bill. Required for SEG applications and supplier switching.
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