Certificate vintage

What does certificate vintage refer to?

Certificate vintage refers to the time the renewable electricity was generated, not the time the certificate was issued or sold. Most registries record vintage at the month level, though some use quarterly or annual granularity. A GoO with a January 2026 vintage represents electricity that was produced in January 2026, regardless of when the certificate enters or exits a holder's account.

Why does certificate vintage matter?

Buyers typically need to match the vintage of their certificates to the consumption period they are claiming against. Many standards and disclosure frameworks require certificates to be from the same reporting year as the consumption being covered, and several increasingly require granular matching at monthly or even hourly resolution, as seen in the emerging 24/7 carbon-free energy movement and the latest revisions to the GHG Protocol Scope 2 Guidance. Using the wrong vintage can invalidate a claim.

How long is a certificate vintage valid?

Validity depends on the scheme. European GoOs are valid for cancellation up to 12 months after the end of the production period; after that, they expire. UK REGOs follow the UK compliance period (April to March), and certificates not used within the relevant compliance year cannot be used to satisfy that year's Fuel Mix Disclosure. US RECs vary by tracking system and by state RPS rule, with some states accepting older vintages and others not.

Can certificate vintages be mixed within a portfolio?

Yes, and most active EAC portfolios contain certificates with multiple vintages across different markets. The complexity is keeping track of which vintages are still usable for which claims, which are approaching expiry, and which buyers or contracts require specific vintages. Stranded certificates (older vintages held past their usability window) can no longer be cancelled to back a claim.