Alectrona
Commercial guideHalf-hourly metering records your site's electricity use in 30-minute blocks across the day, and that data is the single best input for sizing a commercial solar system to your real load.
OrientationThis is a plain-English guide to help you orient before a project, not formal advice. Half-hourly settlement rules and the data your supplier holds vary by site, so we confirm the specifics for your meter before any modelling.
Half-hourly (HH) metering means your supply is settled in 48 readings a day, one for every 30-minute period, rather than a single monthly total. Most larger commercial sites already run on it, often without the finance or facilities team thinking about it, because it is how the electricity market settles supplies above a certain demand threshold.
For a solar project that data is invaluable. A monthly bill tells us how much you used; HH data tells us when. Since a solar array pays its best when its output is consumed on site as it is produced, knowing the shape of your daytime load is what lets us size a system to match it rather than guess at it.
A half-hourly meter, sometimes installed with a separate communications device that reports the readings automatically, records your import in 30-minute blocks and sends those readings to your supplier each day. The result is 48 data points per day, around 17,520 over a year, that together draw a detailed picture of how your site draws power around the clock.
It contrasts with non-half-hourly supplies, which are settled on estimated profiles and periodic readings. HH settlement was historically tied to your maximum demand and the profile class of your meter; the rules have been changing under the industry move to market-wide half-hourly settlement, but the practical point for a commercial buyer is simple. If your site is large enough to be considering solar over 50 kWp, it is very likely already metered half-hourly.
Solar generation follows a predictable daily curve: nothing overnight, rising through the morning, a midday peak, falling away into the evening. Your building has its own demand curve. The value of an array depends almost entirely on how well those two curves overlap, because a unit generated and used on site offsets an expensive imported unit, while a unit exported earns far less.
HH consumption data lets us plot your real demand curve against modelled generation, half-hour by half-hour, across the seasons. That tells us how much of the array's output you would actually consume rather than export, which is the number that drives the whole business case. A monthly total simply cannot show this. Two sites with identical annual consumption can have completely different solar cases depending on whether the load sits in the daytime or after dark.
Where the load runs through the middle of the day, it sits squarely under the generation curve, so a high share of the array's output is consumed on site rather than exported.
Where the load is peaky or weighted into the evening, less of the generation is used as it is produced, which can point toward a smaller array or storage to shift surplus into the demand.
When we model a site, we ask for at least a year of HH consumption data, which your supplier or third-party intermediary can usually export as a CSV. A full year matters because it captures the seasonal swing: winter generation is a fraction of summer, and your own load may rise or fall across the year.
We line that data up against generation modelled for your exact roof, using the geometry from our in-house drone survey rather than a desktop estimate. The output is an honest split of what would be self-consumed versus exported, before any system is specified. That self-consumption figure is what we size around, so the array fits your demand instead of just filling the roof. Where the daytime match is weaker, we model whether storage earns its place rather than overbuilding an array that would export cheaply.
If you are not sure whether your site is on HH metering, your electricity bill usually says so, or your supplier can confirm it in a phone call. The data itself is held by your supplier and, for HH supplies, by a data collector appointed under your contract.
You can request a HH data export directly, typically covering the last 12 months as a spreadsheet. Whether a charge or any conditions apply varies, so check with your supplier when you ask. If you would rather we handle it, we can guide the request, or work from a recent export you already hold. Either way, the modelling does not start from a sales assumption; it starts from your meter.
Half-hourly data is not only held on your meter; it also feeds a national settlement process that decides how much each supplier buys and pays for. That process runs under the Balancing and Settlement Code, administered by Elexon, the body appointed to manage electricity settlement in Great Britain. Your half-hourly readings are collected, aggregated and reconciled through that framework, which is why the data your supplier can export to you is the same data the market settles on. For a buyer modelling solar, that is reassuring: the consumption curve is metered and auditable rather than estimated.
The framework is in the middle of a significant change. Under the Market-wide Half-Hourly Settlement (MHHS) programme, overseen by the energy regulator Ofgem and delivered through Elexon, settlement is moving so that far more supplies are settled on actual half-hourly data rather than estimated profiles. The programme is being rolled out in phases rather than overnight, so the precise rules and timetable that apply to your meter are worth confirming rather than assuming. The practical takeaway for a commercial buyer is unchanged: a site large enough to be weighing solar over 50 kWp is very likely already settled half-hourly today, and the direction of travel only makes granular data more central. We treat the settlement position as orientation and confirm the current position for your meter point before it drives any modelling, in line with our network charges guide.
Half-hourly data shows when you use power, and it shows when that power is most expensive, which is where solar earns disproportionately. Distribution charges, the DUoS element of your bill set by your network operator, are banded by time of day into red, amber and green periods, with the red band covering the highest-cost peak hours on weekday afternoons and early evenings. Because those bands are defined per half-hour, only half-hourly data lets us see how much of your consumption lands in the expensive red and amber windows. Each operator publishes its own charging statement: for sites across Yorkshire and northern and north-east Lincolnshire that operator is Northern Powergrid, and across Greater Manchester and Lancashire it is SP Electricity North West, formerly Electricity North West.
Solar generation peaks around the middle of the day, which overlaps the amber band and the leading edge of the afternoon red period for much of the year. Where your half-hourly profile shows heavy daytime demand running into those bands, each self-consumed unit avoids the wholesale energy cost and the higher distribution charge attached to that half-hour as well, which strengthens the case beyond a flat-rate calculation. Where the profile is flatter or evening-weighted, the data shows that too, and points toward whether shifting surplus with battery storage moves generation into a more valuable window. We work this through against your actual banded charges rather than an averaged tariff, and any payback or return figure that follows stays modelled rather than promised, with the basis stated and the detail held in the commercial finance section. The headline cost framing for a project of this kind is surveyed in our commercial solar cost guide.
When you request an export, half-hourly data usually arrives as a CSV keyed to your meter point, identified by its MPAN, the supply number printed on your bill. Each row carries a date and the 48 half-hourly import values for that day, and a clean twelve-month file is the input our design model wants. Knowing the shape of the file in advance makes the request to your supplier or data collector quicker, because you can ask for the right thing rather than a summary report that strips out the half-hourly detail.
Real exports are rarely perfect, and the gaps matter for honest modelling. Clock changes in spring and autumn produce short and long days in the data and need handling so a missing or doubled period does not distort a season. Communications outages can leave estimated rather than actual readings for some half-hours, which the settlement process later reconciles but a raw export may still show. A change of supplier or meter within the year can split the record across two files. We clean and stitch these before modelling rather than feeding a flawed file straight into the design, because the whole point of using metered data is that the self-consumption split is grounded rather than assumed. This sits alongside the roof side of the model covered in how much roof space, and the two together decide whether a site clears the bar, which is the test set out in our ROI and payback guide.
Your readings pass through a chain of appointed agents before they reach you or us. A half-hourly supply is not served by the supplier alone. Under the Balancing and Settlement Code administered by Elexon, separate parties are appointed against your meter point: a Meter Operator responsible for the metering equipment, and the data services that collect and aggregate the half-hourly readings for settlement. These appointments are recorded against your MPAN, the supply number on your bill, and they are the parties who actually hold the granular interval record rather than a summarised monthly figure.
Access is granted by authorisation from the account holder rather than by owning the meter. Because the data belongs to your supply contract, the usual route is a Letter of Authority: a short signed instruction from the account holder permitting your supplier, or the appointed data service, to release the half-hourly export to a named third party. With that in place the twelve-month file can be sent to us directly, which removes the step of you forwarding it on, and any release condition the agent attaches is dealt with at the same time.
The practical point for a buyer is that arranging access early, alongside the connection thinking in our DNO explained guide, keeps the design moving. We treat the agent appointments and any release conditions as orientation and confirm the current position for your meter point before it drives modelling, in the same way the wider network charges framework is confirmed rather than assumed.
Our own insured pilot flies your roof and captures the real geometry and shading, so the design starts from your building instead of a satellite guess.
Booked to suit your operating hours
We model the array in bankable-grade software, size it around your daytime load, and set out generation, savings and payback across three funding routes.
Modelled, not promised
Designed and installed to BS 7671, commissioned to IEC 62446-1, connected under G99 and run under CDM 2015. Alectrona is typically the Principal Contractor.
Outside MCS, assured by the non-MCS stack
A 12-month defects period backed by an Insurance-Backed Guarantee, then ongoing operations and maintenance so the asset keeps earning for its full working life.
Kept performing, year on year
Your electricity bill usually indicates it, or your supplier can confirm in a short call. As a rule of thumb, sites large enough to be considering commercial solar over 50 kWp are very likely already settled half-hourly, because HH settlement applies to supplies above a certain demand level.
An annual or monthly total tells us how much electricity you use, but not when. Solar earns its best when generation is consumed on site as it is produced, so the value depends on how your demand lines up with the daily generation curve. Two sites with the same annual consumption can have very different solar cases depending on whether the load is daytime or after dark. Half-hourly data is what lets us tell the difference and size accordingly.
We ask for at least 12 months, so the model captures the full seasonal swing in both generation and your own load. Your supplier, or the data collector appointed under your HH contract, can usually export it as a CSV on request.
If you would prefer not to chase it, we can guide the request or work from a recent export you already hold.
Self-consumption is the share of what your array generates that your building uses on the spot, rather than exporting to the grid. It matters because a self-consumed unit offsets an expensive imported unit, while an exported unit earns far less. Sizing the system to maximise sensible self-consumption is the core of getting the economics right, and your half-hourly data is what makes that figure honest rather than assumed.
Request it at the start, before any design work, because the metered profile is what the system is sized around rather than something checked at the end. A twelve-month export from your supplier or appointed data collector typically arrives within a few working days of asking, though timescales vary by supplier and occasionally a charge or condition applies, so confirm when you request it. Getting it early avoids a redesign later, and if you would rather not chase it we can guide the request or work from a recent export you already hold.
The data itself is not the cost driver, and the system price is survey-led rather than set by the metering step. Some suppliers or data collectors apply a small charge or a condition for a twelve-month export, which they confirm when you ask, but that sits apart from the capital figure. The installed cost of a commercial system over 50 kWp comes from the in-house drone survey, the structural and access position and the grid connection, modelled in PV*SOL against this half-hourly data, which the commercial solar cost guide explains in full.
Last updated June 2026
A guide can only take you so far. The figure you get is modelled from your own half-hourly load and a system sized from the on-site drone survey. No obligation, and systems this size sit outside the domestic MCS scheme, so the assurance is the engineering stack.