Guarantee of origin (HKN)

Guarantee of Origin (HKN)

A Guarantee of Origin (Herkunftsnachweis – HKN) is a certified document that proves the generation of electricity from renewable energy sources. It is not used for electricity trading itself, but ensures transparency about the origin of the electricity purchased — for example from solar, wind, hydro, or biomass plants.

How it works

In Germany, guarantees of origin are managed through the Guarantee of Origin Register operated by the German Federal Environment Agency (§79 ff. EEG).

For every megawatt hour (MWh) of renewable electricity generated, a Guarantee of Origin can be issued.

The certificate can be traded independently from the physical electricity flow and transferred to electricity suppliers or end consumers.

Only through the acquisition and cancellation of a Guarantee of Origin may electricity legally be labelled as “green” or “renewable”, for example in the context of:

 • green electricity tariffs
 • corporate green power agreements
 • ESG reporting

Typical applications

 • Companies that want to source CO₂-neutral electricity on a balance-sheet basis
 • Proof of renewable electricity procurement in climate accounting, ESG ratings, or CDP reports
 • Part of electricity supply contracts (e.g. PPAs including transfer of guarantees of origin)
 • Support for certifications such as ISO 50001 or Science Based Targets
 • Separation of the physical electricity flow and legal renewable electricity labeling

Key figures

 • Volume (MWh): Guarantees of Origin are issued per megawatt hour of renewable electricity generated
 • Issuing period and country: indicates the age and geographic origin of generation
 • Technology type: solar, wind, hydro, biomass — visible in the register
 • Additionality: a certificate alone does not automatically mean new renewable capacity is built
 • Cancellation in the register: required to prevent double counting

Summary

Guarantees of Origin are a central instrument for credible and legally compliant labeling of renewable electricity. They create transparency about the actual origin of electricity and allow companies to document sustainability targets — particularly Scope 2 emissions — in a transparent and verifiable way.
For external communication (e.g. marketing electricity as green power), a valid Guarantee of Origin is required.

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