In the European Union, a Proof of Sustainability (PoS) is a regulatory document required to certify biomethane as a renewable energy carrier. Under the framework of the Renewable Energy Directive (RED II/III), it serves as formal evidence that the gas meets the specific environmental and greenhouse gas emission criteria necessary for inclusion in national and EU energy accounting.

To qualify for a PoS, biomethane must demonstrate greenhouse gas (GHG) savings of 65% (and in some cases up to 80%) compared to fossil fuel comparators. This is determined through a Life Cycle Assessment (LCA) that accounts for emissions from feedstock collection, anaerobic digestion, and the upgrading process. Additionally, the PoS confirms that feedstocks—such as agricultural residues or manure—were not sourced from land with high biodiversity or high carbon stock, such as primary forests or peatlands.

The administrative lifecycle of a PoS involves several distinct entities in a specific sequence. First, the biomethane producer compiles data regarding feedstock origin and production efficiency. A third-party auditor or certification body then verifies this information to issue the certificate. Upon injection into the gas grid, the grid operator or a national registrar tracks the volume through a mass balance system, often recording the data in the Union Database (UDB) to prevent double-counting. Finally, the supplier or trader transfers the PoS to the end-user, who utilizes the document to fulfill their specific regulatory requirements.

Producers require the PoS to qualify for financial support mechanisms and to sell their product into regulated renewable energy markets. Without this documentation, the gas is legally treated as conventional natural gas. For the end-user, the document is used to meet mandatory renewable energy targets or, in the case of industrial players under the EU Emissions Trading System (ETS), to zero-rate their emissions. This allows participants to accurately report their carbon footprint and avoid the costs associated with purchasing carbon allowances for the biomethane portion of their energy consumption.

The Proof of Sustainability provides a standardized framework for verifying the environmental attributes of biomethane across the EU. By maintaining a transparent chain of custody, it ensures that the energy carrier contributes effectively to the European Union’s long-term climate and energy security goals.