Half hourly (HH) metering can look complex from the outside. Acronyms everywhere, new line items on your bill, and contract options you may not have seen before. Yet once you break it down, HH gives you clarity and control that standard meters cannot match.
This guide explains HH in plain English. You will learn what is legally required, how charges flow through, and where the hidden savings usually sit. If you manage a large site or a multi site portfolio, these insights can add up to meaningful reductions with minimal disruption.
When you are ready, WeSave will tender bespoke HH prices, manage your Meter Operator (MOP) and Data Collection/Aggregation (DC/DA) appointments, and provide a free HH review so you can act with confidence.
What half hourly metering actually is
An HH meter records your electricity consumption in 30‑minute intervals and sends that data for settlement. This creates a highly accurate profile of when you use power during the day and across seasons. For larger users, that accuracy improves billing, unlocks better‑targeted contracts and reveals efficiency opportunities that standard meters hide.
You can usually identify HH status from your MPAN. Look at the profile class or the first two digits in the top row. For HH, it will show 00 rather than a domestic or non‑half hourly class such as 03 or 05. If in doubt, your bill or supplier can confirm.
Do you need a half hourly meter?
In the UK, HH metering is mandatory for certain maximum demand supplies and for new connections that exceed agreed thresholds. If your site has current transformer (CT) metering, a high Maximum Import Capacity (MIC), or you trigger specific settlement criteria, HH is usually required. Many businesses choose HH voluntarily because the data, billing accuracy and procurement options improve. If you are expanding or consolidating sites, HH metering often becomes the sensible default.
The legal appointments you must have: MOP, DC and DA
Every HH site must have three appointments in place:
- Meter Operator (MOP): installs and maintains the HH meter and communications.
- Data Collector (DC): retrieves your half‑hourly data.
- Data Aggregator (DA): validates and submits that data into industry settlement.
These can be bundled or contracted separately. Charges appear on your supplier bill or via a direct MOP agreement. WeSave can arrange and negotiate MOP/DC/DA on your behalf, ensure appointments align with your contract dates, and make sure the fee structure is transparent.
The HH business agreement in practice
An HH electricity business agreement sets out your unit rates, standing charges, and which non‑energy costs are fixed or passed through. It also records your MIC (in kVA), reactive power terms, and any site‑specific fees. For multi‑site contracts, we synchronise dates and terms to simplify renewals and reporting. The aim is predictable billing without losing the flexibility to act on price or network changes when it helps you.
Fixed versus pass through: what changes and why it matters
On HH contracts you will usually be offered either:
- Fixed: your unit rate and many non‑energy components are bundled into one price per kWh plus a standing charge. Budgeting is easier, though you may pay a premium for certainty.
- Pass‑through: wholesale and supplier margin are agreed, but items such as Distribution Use of System (DUoS), Transmission Network Use of System (TNUoS), Balancing Services Use of System (BSUoS) and losses are charged at actuals. This can lower costs if your load shape is favourable, but bills will vary month to month.
There is also a hybrid approach where selected charges are fixed and others are passed through. The right choice depends on your risk appetite, cash flow needs and the shape of your load curve. Our tender packs model each option against your actual HH data so you can compare on a like‑for‑like basis.
How DUoS, TNUoS, kVA and reactive power flow through
- DUoS: distribution charges that vary by time band. Red, amber and green periods incentivise off‑peak use. Under pass‑through, you will see these bands itemised; under fixed, they are baked into your p/kWh.
- TNUoS: transmission charges that recover the cost of the national grid. Methodology evolves, but the cost still flows through either as a specific line or within your fixed price.
- MIC and availability (kVA): your MIC sets the capacity reserved for your site. You pay an availability charge on that kVA whether or not you use it. If your MIC is set too high, you can overpay each month. If too low, you may face excess capacity charges.
- Reactive power and power factor: poor power factor means you are drawing more current for the same useful power, which increases network losses and can trigger reactive charges. Power factor correction (PFC) equipment can mitigate this.
Understanding these mechanics is the key to savings. HH data lets you right‑size MIC, improve power factor and shift discretionary loads out of peak DUoS bands with minimal operational impact.
How to reduce HH energy costs without disruption
Start with the quick wins:
- Right‑size your MIC: compare your 12‑ to 24‑month HH demand peaks against your contracted kVA. Where safe and practical, apply to reduce MIC to a suitable headroom above actual demand. This often delivers immediate savings on availability charges.
- Improve power factor: ask for a power factor study using your HH data. PFC can be a modest capital expense that pays back quickly through reduced reactive charges and lower maximum currents.
- Shift flexible loads: processes such as EV charging, refrigeration defrost cycles, battery charging, HVAC pre‑cooling/heating and some production steps can often move out of DUoS red bands. Even partial shifts can cut network costs without affecting output.
- Choose the right contract structure: if your load is off‑peak heavy, a pass‑through approach to DUoS can be cheaper. If you need absolute budget certainty, fix more components. Use data to decide, not guesswork.
WeSave packages this into a single HH review. We take your MPAN list, existing contracts and a sample bill, then benchmark fixed versus pass‑through, model DUoS exposure, check MIC, review power factor and tender the market so you see clear, comparable options.
Data benefits you can actually use
Granular HH data supports:
- Accurate budgeting and forecasting.
- Identification of abnormal weekend or night loads.
- Evidence for MIC change applications to your Distribution Network Operator.
- Business cases for on‑site generation, battery storage and demand response.
We can also align procurement with your sustainability goals, including 100% renewable electricity options verified with REGOs.
Simple answers to common HH questions
- Do businesses need half‑hourly meters? Some do under settlement rules and capacity thresholds. Many others benefit from HH for accuracy and control. If you are moving to CT metering or increasing MIC, you will likely need HH.
- What is an electricity business agreement for HH sites? It is your supply contract that defines rates, which charges are fixed or passed through, your MIC, and the legal MOP/DC/DA appointments.
- What is pass‑through versus fixed on HH contracts? Fixed bundles most costs into a single price. Pass‑through charges certain non‑energy items at the actual industry rates, which can save money if your load shape helps.
- How do DUoS, TNUoS and kVA affect my bill? DUoS and TNUoS recover network costs and vary by time and methodology. MIC drives availability charges in kVA each month. Set MIC correctly and avoid red‑band consumption where possible.
- How can I reduce HH costs without disruption? Right‑size MIC, correct power factor, shift flexible loads and choose a contract structure that matches your consumption profile.
How WeSave helps
WeSave provides independent, expert advice and a full market tender for HH sites. We arrange MOP/DC/DA, validate bills, and manage switches end to end with no hidden fees. If you prefer a quick starting point, you can explore current business electricity options and see how suppliers compare. For multi‑utility portfolios, we can coordinate renewals across electricity, gas and water so you have one clear plan and fewer admin headaches.
Useful next steps:
- Compare current business electricity options and request bespoke pricing via our business electricity prices page at www.wesave.co.uk.
- If you are reviewing all utilities together, start with our business energy overview for a single, coordinated tender.
Summary and next step
HH metering is not just a compliance box. It is a toolkit for smarter procurement and lower network charges. Get the basics right, then use your data to adjust MIC, correct power factor and time flexible loads away from peak periods. The result is lower, cleaner, more predictable bills.
Book a free HH review with WeSave. We will analyse your data, tender bespoke HH prices, and manage your MOP/DC/DA so you can focus on operations. Call 01872 495 111, email hello@wesave.co.uk or start online at wesave.co.uk.
Links to help you get started: