Log in to Mijn Fluvius with itsme or eID
Go to mijn.fluvius.be and log in with itsme or your eID (eID requires a card reader and your PIN code). In the main menu, click "Usage" (sometimes labelled "My usage") and choose your connection if you have more than one (e.g. a second address).
Select quarter-hourly values — not daily or monthly totals
When exporting, explicitly choose quarter-hourly values — not daily or monthly totals. This is a common mistake: daily/monthly totals don't carry timestamps and are therefore useless for a correct comparison (dynamic prices and the capacity tariff depend on exactly when you use electricity, not just how much). Then choose the period to export and download the file as CSV.
What's in the CSV: consumption, injection, day/night, validation status
Each quarter-hour is one row in the file: roughly 35,000 rows per year for a single- register connection, more if you have both consumption and injection (solar panels). That stays well under our 50MB upload limit even for several years, but when in doubt: start with one year — already enough for a first, reliable comparison. The file contains your consumption per quarter-hour, split by day/night rate where applicable, your injection (feed-in, e.g. with solar panels) also per quarter-hour, and a validation status per reading: measured (actually read) or estimated (during a temporary outage).
What happens with your data after uploading
Your usage data is used to fairly weigh your current contract against supplier alternatives — never shared with a supplier or third party unless you initiate that yourself. You stay the only one with access to your own profile.
Re-uploading: updates without duplicates
Uploading a new export file updates the existing data (the same quarter-hours get overwritten, no duplicate readings) — handy if you want to periodically use a more recent export.