An introduction to the Green Gas Certification Scheme

The Green Gas Certification Scheme (GGCS) issues, transfers, and retires Renewable Gas Guarantees of Origin (RGGOs) within our registry.

RGGOs are issued to green gas producers for units of green gas injected into the gas grid which displace units of fossil gas. They can then be transferred between a variety of counterparties before being retired and allocated to gas consumers.

The GGCS ensures that only one RGGO is issued for each unit injected, that they are transferred securely, and only ever allocated to one consumer. By doing so we provide certainty that green gases are not double counted.

The GGCS is run by Renewable Energy Assurance Ltd who carry out a range of certification and consumer protection activities all of which promote renewable energy and the circular economy.

Renewable Energy Assurance Ltd is a company limited by guarantee (number 5720606) and is a wholly-owned subsidiary of The Association for Renewable Energy and Clean Technology, a not-for-profit company limited by guarantee (number 04241430).

History of the Scheme

The GGCS was established in 2011 by the Association of Renewable Energy and Clean Technology with the support of our Founder Partners.

In the early years of the Scheme the number of biomethanes producers, traders, and consumers were small and we played a key role in developing the market and building understanding.

We contributed to the 2013 Biomethane Quality Protocol published by the Environment Agency and WRAP which gave the market clarity on biomethane’s end of waste status.

In 2015, we commissioned a report from Ecofys which gave consumers clarity on how RGGOS could be used with the Green House Gas Protocol. You can download the report here and, for the most-up-to-date guidance, see our note here.

Between 2013-2017, we were a key partner within Green Gas Grids and Biosurf, two EU-funded projects mapping and developing the European biomethane industry.

These projects led to the creation of the European Renewable Gas Registry (ERGaR) in 2017. ERGaR serves as a membership organisation for biomethane registries and interested parties across Europe. GGCS has held a board seat since its inception.

In 2019, Renewable Energy Assurance Limited achieved ISO9001 certification of its quality management system.

In 2021 we were listed as an Approved Certification Scheme for compliance with the UK governments Green Gas Levy

Current Status

GGCS issues RGGOs for approximately 80% of all biomethane injection in the UK. As of November 2021, we have over 70 biomethane plants and 90 trading accounts on our registry.

We publish a quarterly report of RGGOs issued and retired which can be provided on request to interested parties. We also publish an annual report. See the news section of the website for recent reports.  


Founder Partners and Associate Members:
British Gas
Thames Water
Milton Keynes Council
National Grid
CNG Services Ltd