The GGCS maintains a conservative approach to any additionality claims that should be made related to gas consumers purchasing Green Gas Certificates.
A Green Gas Certificate guarantees that;
Consumers can check that their GGCS Certificate is genuine here: https://www.greengas.org.uk/certificates/validate
The production of green gas in the UK is financially supported by either the Renewable Heat Incentive (RHI) or the Renewable Transport Fuel Obligation (RTFO).
In that respect no additional green gas can be said to have been directly produced as a result of a gas consumer buying a Green Gas Certificate, and it is important consumers don’t make any such claims. However demand for Certificates “does create an important driver for further growth of green gas production in the UK.” (Ecofys, 2016)