1. Introduction
Biomethane has established itself as one of the renewable gases with the greatest potential within the decarbonisation process promoted by the European Union.
However, the development of the biomethane market does not depend solely on production capacity. Equally important is the existence of mechanisms capable of certifying both the renewable origin of the gas and compliance with the sustainability criteria required under European legislation.
Two key instruments currently underpin the commercialisation and market value of renewable gas: Guarantees of Origin (GoOs) and Proofs of Sustainability (PoS). These mechanisms constitute the principal regulatory and traceability tools currently used across the European biomethane market, enabling market participants to demonstrate the renewable nature and sustainability credentials of biomethane.
European and Spanish Regulatory Framework
Directive (EU) 2024/1788 and Regulation (EU) 2024/1789, which form part of the so-called Gas and Hydrogen Package, establish the European regulatory framework designed to strengthen the integration of renewable and low-carbon gases into the energy market.
In parallel, Directive (EU) 2023/2413 (RED III), amending Directive (EU) 2018/2001 (RED II), reinforces renewable energy development targets and further strengthens the role of renewable fuels in the decarbonisation process.
In Spain, the system governing guarantees of origin for renewable gases is principally regulated by Royal Decree 376/2022 of 17 May and Ministerial Order TED/1026/2022, which establishes the operational framework for the management of the certification system.
2. Guarantees of Origin and Proofs of Sustainability
One of the principal mechanisms driving the commercialisation of renewable gases is the use of Guarantees of Origin (GoOs) and Proofs of Sustainability (PoS) certifications, which function as key traceability tools for biomethane trading across the European Union.
Whilst both mechanisms are closely connected, they serve distinct purposes. Guarantees of Origin – a key commercial asset – certify the renewable nature of the gas supplied, whereas Proofs of Sustainability are intended to demonstrate compliance with the sustainability and greenhouse gas emissions savings criteria established under European legislation.
The bankability of projects, the structuring of supply arrangements and ESG strategies increasingly depend on how these instruments are implemented and integrated into commercial frameworks.
2.1. Guarantees of Origin (GoOs)
Guarantees of Origin are electronic certificates evidencing that a specified quantity of gas (1 MWh) has been produced from renewable sources.
Beyond their technical function, GoOs have become a key commercial instrument within renewable gas markets. In particular, they:
- enable the “green” attribute of gas to be separated from the physical supply itself;
- facilitate the sale, purchase and trading of renewable energy attributes;
- play a central role in power purchase agreements (PPAs), bilateral supply arrangements and ESG reporting; and
- are increasingly designed to operate within a European framework, supported by interoperability mechanisms between national systems (including AIB/EECS schemes).
In order to certify the renewable nature of gas and its principal characteristics, Spain has implemented a national Guarantees of Origin system intended to facilitate the traceability and commercialisation of renewable gases. At present, and on an interim basis, responsibility for administering the system has been entrusted to the Technical System Operator (Gestor Técnico del Sistema – GTS).
From both a legal and commercial perspective, GoOs are essentially declaratory in nature, serving to evidence the renewable origin of the energy supplied, particularly in the context of supply agreements, ESG commitments and broader corporate decarbonisation strategies.
Furthermore, the continued development of the European renewable gas market has encouraged increasing interoperability between national GoO systems, facilitating the cross-border trading of certificates and mutual recognition mechanisms across European jurisdictions.
2.2. Proofs of Sustainability (PoS)
Proofs of Sustainability are intended to demonstrate that renewable gas complies with the requirements established under RED II, including those relating to the sustainability of the feedstocks used; supply chain traceability; and greenhouse gas emissions savings as compared with the relevant fossil fuel comparator.
In addition, the European Union continues to advance the implementation of the Union Database (UDB), conceived as a European traceability system aimed at strengthening oversight of renewable fuels and reducing the risk of double counting.
3. Conclusion
Guarantees of Origin and Proofs of Sustainability are not interchangeable instruments. Rather, together they form the regulatory and commercial foundations of the biomethane market:
- · GoOs enable the renewable attribute of gas to be commercialised; and
- · PoS enable compliance and market access.
As the European biomethane market becomes increasingly sophisticated, the practical importance of certification and traceability mechanisms is expected to grow, particularly in relation to the financing of sustainable projects, corporate emissions reduction commitments and the international trading of environmental certificates.
For market participants, Guarantees of Origin represent the “green currency” that enables businesses to demonstrate to third parties that their gas consumption is derived from renewable sources and that their ESG and climate commitments are supported by verifiable evidence.
Proofs of Sustainability, meanwhile, operate as the regulatory passport required for projects to access key European markets and for financiers, auditors and purchasers to recognise biomethane as a sustainable fuel.
When deployed strategically, GoOs and PoS can transform technically viable biomethane projects into financeable and bankable assets.
For industrial and corporate consumers, these mechanisms provide a means of aligning energy consumption with measurable emissions reduction objectives, sustainability certifications and competitive advantages across supply chains.
Ultimately, the development of the biomethane market in Spain will depend not only on production capacity, but also on the ability of market participants to convert certification into economic value. Whether structuring a biomethane project or reviewing offtake arrangements, this is one of the areas in which legal and strategic advice can deliver significant added value.
