What to ask your client for before a battery study: the data checklist

1. Twelve months of 15-minute data

Peak charges are settled on 15-minute values. In the Netherlands the kWmax is the highest load per clock quarter-hour of the month (Stedin regulation 2024); in Germany the Leistungspreis is set by the year's highest 15-minute load (NEW Netz 2026). A full year is needed because the German peak is annual and because seasons change the load.

Hourly data hides peaks. Illustrative: an hour with three quarter-hours at 300 kW and one at 400 kW averages (3 × 300 + 400) ÷ 4 = 325 kW, but the billed 15-minute peak is 400 kW. A battery sized on the hourly value would be sized for the wrong peak.

2. The 12 invoices for the same months

• The full invoices with every line — network, energy, taxes and levies — not a summary or an annual statement.
• The supply contract type: fixed, variable or dynamic. For a dynamic contract, the price formula (the index and the supplier's markup), because it is contract-specific.
• The invoices are what the rebuilt bill is checked against. Without them, nobody can tell whether the tariff and the data were read correctly.

3. The connection

• The physical connection capacity (kVA or ampere) and, where it exists, the contracted capacity in kW.
• In the Netherlands, also whether the client has asked to lower or raise the contracted capacity in the last 12 months: Liander applies an increase retroactively if a lowered contract is exceeded within 12 months (Liander 2026).
• The voltage level, which decides the tariff category.

4. Solar data, if there are panels

A battery that stores solar needs to know how much is exported and when. Ask for the export channel of the grid meter (import and export as separate columns, or one signed net column) and, if available, the inverter's production data for the same year.

5. What is planned

EV chargers, heat pumps, a new production line or longer opening hours change the case — sometimes from peak shaving to a connection-limit problem. Ask for the kW and the hours each new load will run.

Where the interval data comes from

• Netherlands, large connections (above 3×80 A): the metering company (meetbedrijf) delivers the established quarter-hour values to the grid operator and the supplier's balance party by 10:00 the next day (ACM draft code decision on metering values). Clients usually get them from the metering company's or the supplier's portal. The export formats of those portals are not publicly documented.
• Netherlands, small connections: smart-meter data through the P4 port of the grid operators, with the customer's consent (EnergyID P4 help).
• Germany, load-metered (RLM) sites: the 15-minute Lastgang from the grid operator or metering point operator. Market messages use MSCONS; the current version, AHB 3.2 / MIG 2.5, is valid from 1 October 2026 (Bundesnetzagentur Mitteilung Nr. 56). Portal exports differ by operator; their CSV layouts are mostly not publicly documented.
• Romania: the distribution operator sends measurement data to the supplier for settlement within the first eight working days of the month (ANRE Order 25/2021), and consumption history must cover three years including meter indices (ANRE Order 5/2023). Whether a 15-minute load curve (curba de sarcină) can be downloaded self-service could not be verified; ask the distribution operator or the supplier in writing.
• United States: many utilities offer Green Button data, as a download or through an API (Green Button Alliance).

Some clients simply do not have it. A UK installer writing in POWER Magazine notes that half-hourly consumption data is often not to hand at the client (POWER, 23 Sep 2026). Ask early: getting interval data from a grid operator can take longer than the study itself.

A request you can send

Adapt this to your client:

1. The 15-minute meter data for the grid connection, for the last 12 full months, as exported from the metering or supplier portal (CSV or Excel is fine, unchanged).
2. The invoices for the same 12 months, complete with all pages.
3. The connection capacity and, if you have one, the contracted transport capacity in kW.
4. If you have solar panels: the export data of the same meter and the inverter's production data.
5. Any new loads you plan in the next three years, with their kW and operating hours.

Once the file arrives, run it through the free meter data checker: it reads CSV, Excel, MSCONS and Green Button files in your browser and lists every problem before the study starts. Nothing is uploaded.

Related guides

• The ten data problems that size a battery for you
• Dutch large-connection tariffs: kW contract, kWmax and kWh
• German grid charges for RLM customers and the 2,500-hour rule

Sources

• Stedin, Vergoedingsregeling elektriciteit 2024
• NEW Netz, Preisblatt Strom 2026
• Liander, tariffs for connection and transport, large consumers 2026
• ACM, draft code decision on metering values for large connections
• EnergyID, P4 smart-meter data service help
• Bundesnetzagentur, Mitteilung Nr. 56 on data formats
• ANRE Order 25/2021 and ANRE Order 5/2023
• Green Button Alliance, technical information
• POWER Magazine, The commercial storage gap is not technical, 23 Sep 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.