How do you create STCs in the REC Registry, one at a time or in bulk?

Written and checked by the Energy Merchants desk · Reviewed 3 October 2026 · For installers

Creating STCs means telling the Clean Energy Regulator (CER), through the REC Registry, that a small generation unit has been installed and listing the evidence. Here is the process, with what changes when you do it in bulk.

One system at a time

1. Sign in to your REC Registry account. See registry account setup.
2. Start a new creation for a solar PV system and enter the property address and system size.
3. Add the products. Panel and inverter make, model and serial numbers, which must be on the approved lists.
4. Add the people. Accredited installer and designer details, plus the retailer and owner details.
5. State the installation type. New, replacement or additional. See the installation type guide.
6. Upload the evidence. Photos, assignment form and retailer written statement. See the photo requirements.
7. Review and submit. The registry calculates the number of STCs from the system size, zone rating and deeming period. Compare with the STC calculator.
8. Track status. See status meanings.

Bulk and CSV upload

If you create certificates in volume, the registry supports uploading many systems using a template file in CSV format provided by the CER. In outline:

• Download the current template. Do not rebuild it by hand, since column changes break uploads.
• Fill in one row per system, with serials in the right fields and addresses in the registry format.
• Validate in a spreadsheet first: no duplicate serials, no blank mandatory fields, no stray spaces or date format changes.
• Upload, review the registry’s error report, correct and re-upload.
• Attach evidence per system, which may still need individual handling.

Check the CER guidance for the latest template and file requirements, since they change when the scheme does.

The errors that sink bulk uploads

• A row copied down, creating duplicate serials.
• Dates in the wrong format after spreadsheet edits.
• Addresses that differ from the form. See why STCs fail on photos, serials and addresses.
• Using an old template after a rule change.

What this means for installers

Self-creation gives control and takes time. Most installers weigh that against assigning to a trader, as covered in is it worth self-registering. If you assign, the trader creates the certificates and your job is to supply clean evidence. At Energy Merchants, the compliance desk checks the pack before lodging. See also STC trading.

Checking the numbers

Before you submit, compare the number of certificates the registry calculates with your own estimate. The size, zone and deeming years drive the figure, and the deeming period is five years for 2026 installs and four for 2027. A large gap usually means a wrong postcode, wrong system size or wrong installation date. See deeming period and zone ratings.