The Green Gas Certification Scheme tracks the value of green gas through the supply chain. The Scheme enables consumers to evidence their use of biomethane with a GGCS Green Gas Certificate knowing that the Renewable Gas Guarantees of Origin (RGGOs) it contains are backed by a secure system that ensures against double counting at all stages. The Scheme has been running since 2011 and is the largest of its kind in the UK. Over 400,000 households are on green gas tariffs backed by GGCS Green Gas Certificates, while the majority of the major non-domestic gas suppliers are part of the Scheme and are supplying green gas to an increasing range of organisations from the corporate, public and voluntary sectors. For more information visit – www.greengas.org.uk The GGCS is run by the Association for Renewable Energy and Clean Technology's subsidiary, Renewable Energy Assurance Ltd.