How to get your usage file

Ilvera needs a CSV file of your half-hourly electricity readings. Your file is read in your browser and never uploaded.

Octopus Energy customers

1. On a computer, sign in to your Octopus online account. The date picker is fiddly on a phone.
2. Open your electricity usage page.
3. Use its download option to get your half-hourly readings as a CSV.
4. Pick the last 12 months. A full year gives the fairest comparison, because winter and summer use are very different.
5. Upload the file on Check my usage exactly as it is. No editing needed.

Octopus changes its dashboard from time to time. If these steps don’t match what you see, look for a download or export option on the electricity usage page.

Other suppliers

We don’t read other suppliers’ download files yet. If yours lets you download half-hourly readings, you can rearrange them into this two-column format (a spreadsheet can do it):

interval_start_utc,kwh
2025-10-01T00:00:00Z,0.183
2025-10-01T00:30:00Z,0.161

One row per half-hour, with the start time in UTC (the Z at the end) and the electricity used in kWh.

If something goes wrong

• “Line 1: expected the header…” means we don’t recognise the file’s format. Check it’s the half-hourly electricity file, not daily, gas or costs only.
• A low-coverage warning means some half-hours were missing from the file. We leave gaps out instead of guessing, so a longer date range usually fixes it.
• Only daily or monthly readings? Your supplier may not be collecting half-hourly data. You can usually ask them to.