Large connections: the metering company
- The metering company delivers the established values for every telemetry-read large connection by the next calendar day before 10:00, to the grid operator and the balance responsible party. The values are checked for completeness: every measurement period present, each with a value (ACM draft code decision on metering values).
- These are the values the transport bill is built on: the kWmax is the highest load per clock quarter-hour of the month (Stedin regulation 2024).
- The client may know the data under the name of the metering company, the supplier or an energy-monitoring service. Ask which of them the site uses, then ask that party for the export.
- The export formats of metering-company, supplier and aggregator portals are not publicly documented; Zorowatt's research found none. Expect differences in layout, units and time labels from one portal to the next.
Small connections: P4
- P4 gives third parties access to smart-meter data through the grid operators' central systems, with the customer's consent (EnergyID P4 help; Eneco code of conduct).
- Becoming a P4 data-service party requires an onboarding process, and the granularity available for small businesses could not be verified in the research. Treat P4 as a route to check, not a promise of 15-minute data.
What the file must contain
- The connection's EAN code, as on the invoice, so the file can be matched to it.
- Twelve consecutive months of quarter-hour values, with dates and times.
- Import and, if the site has solar, export (teruglevering) as separate columns, or one signed column with the sign convention stated.
- The unit: kWh per quarter-hour or average kW. At 15 minutes, kW = 4 × kWh.
- Whether the time stamps mark the start or the end of each quarter-hour, and whether they follow daylight saving time.
Check it against the invoice
- Each month's sum of kWh should match the invoiced kWh, and each month's highest quarter-hour the invoiced kW max.
- A small, steady difference can be legitimate. Stedin applies a 1.4% correction to the measured consumption of a medium-voltage connection metered on the low-voltage side (Stedin regulation 2026, art. 5(11)). Find out whether the site has such a correction before calling the difference an error.
- A factor of 4 points at kW read as kWh; a one-hour shift around the end of March or October points at daylight saving. The ten data problems that size a battery for you lists the rest.
Why timing matters more from 2028
Under the ACM's draft decision of 8 October 2026, the kWmax would be weighted by the month, the hour and the type of day from 1 January 2028 (ACM draft). A quarter-hour labelled one hour late would then be weighted with the wrong hour's weight. Getting the time stamps right becomes part of getting the bill right. See ACM 2028: the time-weighted kWmax.
A request you can send
- The quarter-hour import and export values for EAN [code], from [first day] to [last day] (12 full months), exported unchanged from your metering or supplier portal.
- The unit of the values and whether each time stamp marks the start or the end of the quarter-hour.
- The invoices for the same months, complete.
- The contracted transport capacity in kW and any change requested in the last 12 months.
Run the file through the free meter data checker when it arrives: it reads the export in your browser, shows what it assumed about layout, unit and time labels, and lists every gap, duplicate and spike. Nothing is uploaded.
Frequently asked questions
- Is the portal data the same as what is billed?
- It should be the same established values used for settlement, but corrections, estimates and later re-deliveries can make small differences. That is why each month is checked against its invoice before the data is used for sizing.
- How long does it take to get the data?
- No general figure was found for the Netherlands. Ask on the first call: getting a file out of a portal or a metering company can take longer than the study itself.
- Can a small business get quarter-hour data?
- Possibly through P4, with the customer's consent, but the granularity available for small connections could not be verified. If it is not available, say in the report that the peaks are estimated.
- Which file formats can Zorowatt read?
- CSV and Excel exports in long or wide layout, in kWh or kW, meter registers, MSCONS and Green Button. Send the file as exported; an edited file loses the clues the importer uses.
Related guides
- What to ask your client for before a battery study
- The ten data problems that size a battery for you
- Dutch large-connection tariffs: kW contract, kWmax and kWh
Sources
- ACM, draft code decision on metering values for large connections
- Stedin, Vergoedingsregeling elektriciteit 2024 and tariffs and compensation scheme 2026
- EnergyID, P4 smart-meter data service help
- Eneco, code of conduct for other service providers
- ACM, draft code decision on time-dependent tariffs for large connections, 8 Oct 2026
Last checked: 2026-10-30. Every figure in this guide comes from the source linked next to it, with the retrieval date Zorowatt's research recorded (28–30 October 2026), or from arithmetic shown step by step.
Stuck on something else? Ask the community.
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