Scheme Rules (Version 3)

Green Gas Certification Scheme (GGCS) Scheme Rules

This document sets out the Scheme Rules for participating in the Green Gas Certification Scheme (the Scheme). You can download the Scheme Rules as a PDF here.
These Rules are effective from Friday 1st May 2020, replacing;

Version 2 of the Scheme Rules in force between June 2018 and Thursday 30th April 2020 (download here).
Version 1 of the Scheme Rules in force between 2011 and May 2018 (download here).

1. Introduction

The Scheme is a voluntary scheme administered by Renewable Energy Assurance Limited (REAL), a wholly owned subsidiary of The Association for Renewable Energy and Clean Technology (REA).
This document describes the respective roles of Scheme Participants and the Scheme Administrator within the Scheme.
Definitions of key terms can be found in the Appendix of this document.

2. Object and benefit of the Scheme

The objects of the Scheme are to:
1. track Green Gas produced from eligible renewable sources as defined in Rule 3, from Gas Producer to End-Use Consumer by issuing one Renewable Gas Guarantee of Origin (RGGO) for each kWh of Green Gas injected into a Distribution Network and;
2. provide a secure platform for the trade of RGGOs between Scheme Participants.
The Scheme does not track physical flows of Green
Each unit of Green Gas injected into a Distribution Network displaces a unit of fossil-derived gas, providing savings in greenhouse gas (GHG)
The Scheme is a reliable means of ensuring that there is no double-counting or double-selling of Green Gas. It promotes confidence in the renewable energy sector and encourages Gas Producers to inject their Green Gas into a Distribution Network as an alternative to using it to generate
The Scheme is primarily a system for tracking Green Gas within the United Kingdom. However the Scheme cooperates with other European biomethane registries regarding the import and export of RGGOs, and may operate in other jurisdictions where such operations are to the benefit of the Scheme and support greater amounts of Green Gas to be produced and consumed.

3. Defining Green Gas

In order for the Scheme to issue RGGOs Green Gas must comply with the following criteria:
1. be a gas produced from a renewable source, that has lower GHG emissions from its production and consumption than an equivalent fossil fuel product; and
2. meet the quality requirements of the Distribution Network into which it is being injected. For injection into GDN and NTS these requirements are set out in the Gas Safety (Management) Regulations 1996.
Subject to complying with the criteria above, examples of Green Gas include, but are not limited to:
1. methane produced from renewable materials through a biological, chemical or physical process that results in lower GHG emissions from its production and consumption in comparison to the fossil gas that it replaces. This may include biomethane from anaerobic digestion and Biogenic Synthetic Natural Gas (Bio-SNG) from gasification or pyrolysis.
2. propane produced from renewable materials through a biological, chemical or physical process, that results in lower GHG emissions from its production and consumption in comparison to the fossil gas that it replaces.
3. hydrogen produced from the electrolysis of water using renewable energy, that results in lower GHG emissions from its production and consumption in comparison to the fossil gas that it replaces. Such hydrogen may be combined with carbon dioxide to create methane.
When considering whether a gas qualifies as a Green Gas, and is eligible to be issued with a RGGO, the Scheme will consult with the Oversight Panel. The Scheme will consider established practice and suitable evidence, including where appropriate the Directives of the European Parliament and Council, and sustainability criteria within government support mechanisms such as the Renewable Heat Incentive (RHI) and the Renewable Transport Fuel Obligation (RTFO).

4. Government support for Green Gas

The Scheme pays due regard to any support mechanisms provided by the UK Government for the production or consumption of Green Gas. RGGOs and Retirement Statements include relevant information on such support mechanisms.
The Scheme seeks to align itself with the processes of both the RHI and the RTFO where such alignment creates reporting and compliance efficiencies for Scheme Participants, and provides additional assurances for End-Use Consumers.
Where the Scheme operates in, or is involved with, jurisdictions outside the UK, the Scheme may have regard to regulatory regimes and support mechanisms that operate in those jurisdictions.
RGGOs issued by the GGCS or imported from other biomethane registries do not count towards the UK’s share of energy from renewable sources in its gross final consumption, as currently calculated under Article 3 of the European Union’s Renewable Energy Directive, nor will they count towards any equivalent national target that may be created in the UK in the future.
RGGOs exported to other registries and/or allocated to consumers outside the UK, do not count towards any other countries share of energy from renewable sources in its gross final consumption, under Article 3 of the European Union’s Renewable Energy Directive, or any other equivalent target.

5. Start date for the Scheme

The Scheme began operation in March 2011. Its founder partners were British Gas, E.ON, Thames Water, National Grid, Bio Group, Milton Keynes Council and CNG Services Ltd.

6. Taking part in the Scheme

Participation in the Scheme is voluntary and is open to businesses involved in producing Green Gas and businesses wishing to trade RGGOs and retire them on behalf of End-Use Consumers.
Participants must;
1. complete a registration form provided by the Scheme,
2. agree to abide by the Scheme Rules and:
3. sign a letter agreement with the Scheme Administrator.
The Scheme Administrator implements a ‘know your customer’ process in order to satisfy itself that applicants to become Scheme Participants will act with integrity, comply with the Scheme Rules and the law of the domain in which they operate.
Other organisations with an interest in Green Gas may wish to join the Scheme as Associate Members and must also meet the criteria in 6.2.
Should the letter agreement between a Scheme Administrator and a Scheme Participant terminate for any reason then that Scheme Participant will immediately cease to;
1. describe itself as being a member of, or participant in, the Scheme; or
2. use the GGCS’s logo.

7. Scheme Administrator

The Scheme Administrator is responsible for the day-to-day running of the Scheme.
The Scheme Administrator provides access to the Registration Database for Scheme Participants via a secure website that enables the Scheme to Gas Producers and Account Holders, auditors and End-Use Consumers each have access to designated areas of the website.
When Gas Producers and Account Holders join the Scheme they are registered on the Registration Database by the Scheme Administrator and an account set up in their This provides Scheme Participants with access to the relevant sections of the Registration Database.
The Scheme Administrator designs, implements and administers an audit programme to give comfort to Scheme Participants and End-Use Consumers in the integrity of the Scheme. The Scheme Administrator sets the scope of the audit programme in consultation with the Oversight Panel.
To enable these audits Scheme Participants must respond to reasonable requests for records relating to participation in the Scheme and deliver such records to the Scheme Administrator, or any person appointed by the Scheme Administrator to monitor compliance with the Scheme.

8. Gas Producers

Participating Gas Producers are required, on a regular basis, to make Production Declarations regarding the amount of Green Gas they have injected into a Distribution Network, in accordance with guidance issued by the Scheme Administrator. Gas Producers may inject gas which is wholly Green Gas or they may inject a mixture of fossil gas and Green Gas. Only the Green Gas portion of a mixed gas injection is issued with RGGOs.
Production Declarations must provide evidence to show that Green Gas injected into a Distribution Network for which the issue of RGGOs is being requested, complies with the criteria in Rule 3.
Where the Gas Producer is claiming RHI support for all of its Green Gas injection, the amount of Green Gas recorded in its Production Declaration shall be the same as that which has been registered with Ofgem for RHI purposes, on a three-monthly Independent meter readings, as submitted to Ofgem, should support the information within the Production Declaration and must be disclosed by the Gas Producer to the Scheme Administrator and Scheme auditors on request.
Where there is an amount of Green Gas recorded in a Production Declaration for which RHI support has not been claimed, supporting evidence of the Green Gas production should be based on a robust methodology that meets a recognised standard, such as the GGCS Data Verification Statement process, ISAE 3000, or a voluntary scheme recognised by the European Commission.
For each kWh of Green Gas injected into a Distribution Network that displaces the need for a unit of fossil gas, the Scheme will issue a RGGO, subject to any corrections including but not limited to subtracting any units of fossil gas used in the production process.
RGGOs can be transferred to Account Holders and then retired and allocated to End-Use
Gas Producers shall not register the same units of Green Gas registered under the Scheme in any other scheme which has similar aims, for example where that registration would lead to the creation of any kind of Energy Attribute Certificate (EAC) equivalent to the RGGOs that the Scheme creates.
Gas Producers shall provide the Scheme Administrator with independently verified details of their production facilities on request.
On an annual basis Gas Producers shall provide the Scheme Administrator with independent verification of the data they have submitted to the Scheme in respect of their feedstock inputs and Green Gas outputs.
Gas Producers will inform the Scheme Administrator at the earliest opportunity of any information which may give rise to the need for RGGOs to be withdrawn.
Gas Producers agree that information about their production facilities and their Green Gas outputs contained within RGGOs will be shared with Account Holders and End-Use Consumers when RGGOs are transferred or allocated to them.

9. Account Holders

Account Holders have the ability to receive into their accounts RGGOs offered to them by Gas Producers and other Account Holders.
Account Holders may initiate Transfer Requests by logging into the secure area of the Registration Database to enter the required information.
The UK is linked to the European gas grid. As such, Account Holders are able to allocate RGGOs to End-Use Consumers based outside the UK and generate Retirement Statements accordingly.
The Scheme Administrator provides guidance to Account Holders on the use of the Scheme when allocating RGGOs to non-UK End-Use Consumers and on the potential to transfer RGGOs to equivalent Schemes operating in other countries.
When transferring RGGOs to other Account Holders or allocating RGGO to End-Use Consumers either inside or outside the UK, Scheme Participants should make those parties aware of any financial support the UK Government has provided to the Gas Producer in respect of whose Green Gas those RGGOs have been issued. It is important to note that RGGOs generated by the Scheme do not in and of themselves, entitle their owner to claim any consumption subsidy that may be payable inside or outside of the UK.
Account Holders marketing Green Gas Tariffs should pay due regard to Section 21 “Marketing Green Gas” and Rule 10.5 and must put in place robust processes to ensure that they are meeting their commitments to End-Use Consumers signed up to that Tariff by retiring an appropriate quantity of RGGOs.
As per Rule 7.5 Account Holders must respond to reasonable requests for information from the Scheme Administrator in respect of the operation of their Green Gas Tariffs. They should pay due regard to any guidance issued by the Scheme in relation to Green Gas Tariffs.

10. Allocating RGGOs to End-Use Consumers

End-Use Consumers are parties who are allocated RGGOs in respect of gas they have consumed. They may be domestic or non-domestic gas consumers and may be allocated RGGOs individually or as a group where they have signed up to a Green Gas Tariff.
The gas they have consumed must have been withdrawn from the same Distribution Network into which the Green Gas, represented by the RGGOs they have been allocated, was injected.
End-Use Consumers may be allocated RGGOs by any Account Holder participating in the Scheme.
Account Holders allocate RGGOs to an End-Use Consumer by naming them when making a Retirement Request. A Retirement Statement listing the relevant RGGOs is then automatically generated in the End-Use Consumer's name. The relevant RGGOs are retired and the Registration Database logs them as allocated to that End-Use Consumer.
Where Account Holders decide to offer domestic or non-domestic End-Use Consumers a Green Gas Tariff that is made up of a proportion of Green Gas, only RGGOs equivalent to the Green Gas proportion of the total are retired and listed on a Retirement Statement.
Allocation of RGGOs to an End-Use Consumer may represent a claim of Green Gas use based on the principles of Book and Claim or on the principles of Mass Balance.
Mass Balance claims may require Scheme Participants to provide evidence to the Scheme Administrator of the chain of custody of the physical gas, being units of Green Gas injected into a Distribution Network.
The European gas grid can be defined as a single Distribution Network and consumers connected to that grid outside of the UK can be allocated RGGOs generated in respect of Green Gas injected within the UK, and make a claim of Green Gas use.
When allocating RGGOs to an End-Use Consumer not domiciled in the United Kingdom Account Holders should take into consideration the importance of evidencing movement of gas between countries connected to the European gas grid. Information could include; data on gas flows, the opinions, guidance documents and verification processes of UK Government regulators such as the Department for Transport, statements by non-UK governments, and statements from non-governmental bodies such as the CDP and the European Renewable Gas Registry (ERGaR).

11. Associate Members

GDNOs, and other parties involved in the gas industry, who wish to support the development of the Green Gas sector, but who do not produce Green Gas or trade RGGOs, may participate in the Scheme as Associate Members.

12. Issuing Renewable Gas Guarantees of Origin

When a Gas Producer submits to the Scheme a Production Declaration regarding Green Gas injected into a Distribution Network and containing the necessary evidence, the Registration Database issues a RGGO for each unit of Green Gas injected.
RGGOs record:
1. the identity of the Gas Producer,
2. the technology by which the Green Gas was produced,
3. the feedstock that was used in the Green Gas production process,
4. the kWh number, or sequence/range of kWh numbers, relating to that Gas Producer’s Green Gas injection into a Distribution Network over a given time period,
5. the location and Distribution Network into which the Green Gas was injected,
6. the time period over which the Green Gas was injected,
7. information regarding any financial support, such as the RHI, that a Green Gas may have received.
The Scheme provides information on its website about the different technologies and feedstocks used to produce Green Gas as well as information about the identity of Gas Producers participating in the Scheme.
The Scheme Administrator takes reasonable measures to ensure the accuracy of the meter readings on which RGGOs are issued, and, where relevant compares the Green Gas registered on the Registration Database with submissions provided to Ofgem for RHI purposes.
When issuing RGGOs the Scheme Administrator is provided with evidence of the environmental attributes of the Green Gas they are issued in respect of. This evidence may come from the processes of the RHI or the RTFO or be provided by a voluntary scheme recognised by the European Commission.
Where RGGOs are issued in respect of Green Gas for which a Gas Producer has made a claim for a RHI support payment, the Gas Producer must provide evidence to the Scheme that the Green Gas has met the RHI sustainability criteria set out by Ofgem.
Where RGGOs are issued in respect of Green Gas where no claim for a RHI support payment has been made, evidence must be provided to the Scheme that the environmental attributes of the Green Gas meet an alternative set of sustainability criteria which may be:
1. the carbon and sustainability criteria within the RTFO,
2. the sustainability criteria for biofuels, bio-liquids and biomass fuels set by the European Commission,
  or the equivalent United Kingdom authority responsible for setting such criteria.

13. Withdrawing RGGOs

The Scheme has adopted robust and auditable processes for issuing RGGOs. However, after issuing such RGGOs, the Scheme Administrator may become aware of:
1. errors in the quantity of Green Gas injected,
2. non-compliance with the requirements set out in Rule 3,
3. information that would otherwise affect the information recorded in the RGGOs or their value.
If such a situation arises the Scheme Administrator will, in the first instance, seek to correct errors by attributing RGGOs issued in respect of the non-compliant injection towards a subsequent equivalent injection by the relevant Gas Producer of compliant Green Gas.
If such a correction is not possible or practical the Scheme Administrator may declare the injection non-compliant and withdraw the RGGOs issued in respect of that Green Gas.
Where RGGOs are withdrawn the Scheme Administrator will, as soon as reasonably practicable, notify the Gas Producer into whose account the RGGOs were originally issued and, if applicable, the Account Holder who is holding the RGGOs at the time of withdrawal.
Where the withdrawn RGGOs have already been retired and allocated to an End-Use Consumer, the Scheme Administrator will, as soon as reasonably practicable, notify the Scheme Participant who issued a Retirement Request for the RGGOs. That Scheme Participant must notify the End-Use Consumer who has been allocated the RGGOs that those RGGOs have been withdrawn and verify that they have done this to the Scheme Administrator.
Withdrawn RGGOs are not available to be transferred to other Account Holders or to be allocated to End-Use Consumers.
The Scheme Administrator may publish a list of withdrawn RGGOs where it deems it to be necessary or desirable.

14. Retiring RGGOs

When an Account Holder makes a Retirement Request the Registration Database issues an electronic Retirement Statement that allocates RGGOs to an End-Use Consumer.
The Retirement Statement lists the RGGOs that have been retired. It is the guarantee of the authenticity and origin of the equivalent amount of Green Gas injected into a Distribution Network.
The Retirement Statement can be downloaded in PDF format. The End-Use Consumer or the Account Holder, in making any claims concerning the use of Green Gas, whether for regulatory or commercial purposes, must back up the claim with the relevant RGGOs listed on a Retirement Statement.

15. Expiry of RGGOs

If, three years and three months after the date of the injection of Green Gas into a Distribution Network, RGGOs created in respect of that Green Gas have not been retired or withdrawn, they will expire and will no longer be available to Gas Producers or Account Holders.
The Scheme will provide guidance to Scheme Participants on how the Registration Database will calculate the date of injection of Green Gas and the three year three month period.

16. Verifying Retirement Statements

The Scheme website provides a function for End-Use Consumers to verify Retirement Statements

17. Back-up and security

The Scheme Administrator uses all reasonable endeavours to ensure that the Registration Database is protected against fraudulent use and remains operational for the duration of the Scheme, while complying with relevant data protection laws.
The attributes of the Registration Database are described on the Scheme’s website.

18. Confidentiality

The Scheme Administrator agrees not to disclose information regarding any Transfer Requests or Retirement Statements to third parties without the express permission of the Scheme Participants
Confidentiality clauses are included in letter agreements signed by Scheme Participants.

19. Auditing

The Scheme Administrator maintains arrangements for auditing the accuracy of the meter readings on which RGGOs are issued. Such audits take place both regularly and on a random basis.
The Scheme Administrator maintains arrangements for auditing a representative sample of Transfer Requests, transfers, Retirement Requests and Retirement Statements on an annual basis. Audits are carried out both regularly and on a random basis.
The Scheme Administrator instructs an independent auditor to verify that the Scheme Administrator is meeting its obligations to Scheme Participants and that the Scheme is meetings its objects.
The Scheme Administrator consults with the Oversight Panel annually on the scope of its auditing activity.

20. Fees

The Scheme Administrator operates on a not-for-profit basis and does not aim to produce a material surplus of income over running costs. The Scheme is designed to be simple and low cost to operate. Fees are calculated to cover the costs of administering the Scheme and Registration Database, the costs of auditing the Scheme and Scheme Participants, as well as appropriate governance costs.
The fees payable for participating in the Scheme are broken down into the two categories outlined below.
1. Scheme Participants are required to pay an annual participation fee. The annual participation fee is £500 per annum (unless otherwise adjusted by the Scheme Administrator after consultation with the Oversight Panel). This is invoiced at the start of the calendar year or charged a pro rata basis for those who join during the year.
2. Participating Account Holders are required to pay the Scheme Administrator a RGGO retirement fee which is a charge levied on an Account Holder’s aggregate retirement of RGGOs to End-Use Consumers, at the point Retirement Requests are registered on the Registration Database. This fee is currently set at 0.0095p per kWh. Any changes to this fee will only be made with the agreement of the Oversight Panel. The Registration Database automatically reports on RGGO retirements so that an invoice can be raised for each participating Account Holder at the end of each month during which RGGOs have been retired and allocated to a End-Use Consumer . Account Holders have 30 days to settle the invoice.
The fees are set annually by the Oversight Panel. In reaching a decision, the Panel takes into account the number of Scheme Participants and Associate Members, the volume of RGGOs being retired and the running costs of the Scheme. A budget is prepared by the Scheme Administrator for this purpose.

21. Marketing Green Gas

Scheme Participants should take a conservative approach in making any claims that their purchase or sales of RGGOs, and payment of fees to the Scheme, create any additionality in the amount of Green Gas being produced.
They should pay due regard to any guidance on additionality claims published by the Scheme which are made available on the Scheme website.
Scheme Participants must be honest and transparent when marketing Green Gas to End-Use Consumers. In accordance with Rule 2.2 they should not claim that the allocation of RGGOs represents the physical supply of Green Gas to an End-Use Consumer. Where appropriate the process of issuing, transferring and retiring RGGOs should be explained.
Scheme Participants may use the Scheme’s logo in accordance with the Scheme Administrator’s guidance.

22. Reporting

The Registration Database allows for a full range of reports to be run on theRegistration Database. A number of reports are publicly available while others are restricted to Scheme Participants.
In addition, the Scheme Administrator produces an annual report which details the operation of the Scheme over the preceding year which includes information on the amount of Green Gas registered and RGGOs issued and retired.

23. Governance

Scheme Participants, who have paid the relevant fees, agreed to the terms of the letter agreement and completed the relevant registration forms, are members of the Oversight Panel.
The Oversight Panel has an independent Chair.
The Oversight Panel meets twice a year but may hold additional meetings at the request of the Scheme Administrator or Scheme Participants.
Independent parties, End-Use Consumers, environmental group representatives and other stakeholders may attend and participate in Oversight Panel meetings, either at the invitation of the Oversight Panel or as appointed by the Scheme Administrator
The Oversight Panel considers the results of audits and is consulted on rule changes. It also discusses the budget for the Scheme and agrees the fee levels on an annual basis.
The Oversight Panel’s Terms of Reference are set and amended as necessary by the Panel.
The day to day running of the Scheme is undertaken by the Scheme Administrator. In addition to the Scheme Rules, and the terms of letter agreements signed by Scheme Participants, the Scheme Administrator issues guidance documents. This allows Scheme Participants to make best use of the Scheme and ensure it is used in a way that encourages confidence and understanding of the Green Gas market.
The Directors of REAL fulfil their obligations including filing accounts with Companies House, ensuring the company meets its statutory obligations and making strategic and high-level operational decisions about the Scheme.

24. Links to other schemes

REAL administers various consumer codes and certification schemes including the Biofertiliser Certification Scheme and the Compost Certification Scheme. A full list is available on the website: www.realschemes.org.uk.
There is no obligation on Scheme Participants to participate in any other scheme operated by REAL or to be members of The Association for Renewable Energy and Clean Technology (REA).
The Scheme is a member of ERGaR - www.ergar.org. This links the Scheme to other European Green Gas registries. Documentation relating to the Scheme’s membership of ERGaR is available to Scheme Participants on request.
The Scheme has a cooperation agreement with the German Energy Agency (DENA) - www.dena.de - which facilitates the transfer of RGGOs between the GGCS and the German Biogas Register.

Appendix A: Roles and responsibilities of Scheme Participants

A Gas Producer:

elects and agrees to take part in the Scheme
arranges for Green Gas to be injected into a Distribution Network
submits Production Declarations to the Scheme Administrator regarding the quantity of Green Gas injection into a Distribution Network
provides proof of such Green Gas injections and that they have met relevant sustainability criteria
independently verifies the data submitted to the Scheme Administrator on an annual basis
is issued with RGGOs for each kWh equivalent of Green Gas injected
makes Transfer Requests in order to transfer RGGOs to Account Holders
agrees for its processes to be audited annually on a random and spot check basis
agrees not to make claims that cannot be substantiated in relation to the Green Gas

An Account Holder:

elects and agrees to take part in the Scheme
accepts or rejects requests from Gas Producers and other Account Holders to have RGGOs transferred into its account
submits Transfer Requests to transfer RGGOs to other Account Holders’ accounts
submits Retirement Requests in order to retire RGGOs and allocates them to End-Use Consumer(s)
provides Retirement Statements to (an) End-Use Consumer(s)
agrees to pay the Scheme Administrator’s invoices in respect of the RGGO retirement fee
agrees for its processes to be audited on a random or at risk basis
agrees not to make claims that cannot be substantiated in relation to the Green Gas

An End-Use Consumer:

receives a Retirement Statement from an Account Holder which signifies the retired RGGOs that have been allocated to them and on this basis can make a claim to have used Green Gas.
can verify the authenticity of a Retirement Statement by using the on-line secure facility
agrees not to make claims that cannot be substantiated in relation to the Green Gas purchased

The Scheme Administrator:

contracts with all Scheme Participants
contracts with independent auditor(s)
monitors the operation and maintenance of the Registration Database and that the issuing of RGGOs and transfers of RGGOs are carried out correctly
ensures Scheme Participants are registered on the Registration Database and are provided with a user name and secure password
issues invoices for the annual participation fee on an annual basis
issues invoices for RGGO retirement fee on a monthly basis
maintains appropriate governance arrangements to ensure an open, transparent scheme
promotes the Scheme
reports regularly on the Scheme to the Oversight Panel

The Scheme Auditor:

audits the Scheme
recommends improvements to the

The Oversight Panel:

agrees its Terms of Reference
seeks to meet twice a year to oversee the Scheme and propose changes to it
considers the results of the audits
is consulted on rule changes
discusses the budget for the Scheme
agrees the fee levels on an annual basis
ensures that the Scheme is open and transparent.

Appendix B: Definitions of Key Terms

Account Holder	an individual or corporate body, who registers with the Scheme and is provided with access to a secure area of the Registration Database for the purposes of accepting transfers of RGGOs and initiating Transfer Requests and Retirement Requests.
Book and Claim	A Book and Claim approach means that trade of an EAC is not linked to the trade of the physical product however rule 10.2 must be applied
Distribution Network	a system for transporting gas from a Gas Producer to an End-Use Consumer. Distribution Networks include the NTS, GDN, gas transportation infrastructure operated by IGTs (whether or not connected to the NTS or a GDN) and systems of distribution via bottles and tankers that form a distinct network.
EAC	Energy Attribute Certificate (EAC) being a market instrument that is created to represent the renewable and/or sustainable value of a unit of energy generation. Parties purchasing and retiring EACs may make a claim that they have used the renewable energy that an EAC represents.
End-Use Consumer	any person who is allocated RGGOs in respect of gas consumed from the same Distribution Network into which the Green Gas that the RGGOs relate to was injected.
ERGaR	European Renewable Gas Registry
GDN	Gas Distribution Networks being the Local Gas Distribution Zones as defined in TPDA 1.2.2 of the UNC.
Gas Distribution Network Operator (GDNO)	as defined in the UNC, a person which is, and in its capacity as, the owner or operator of one or more LDZ(s) and licensee under a Transporter’s Licence authorizing the conveyance of gas through such LDZs.
Gas Producer	an individual or corporate body which produces Green Gas
Gas Supplier	the holder of a license issued by the Secretary of State pursuant to section 7A(1) or 7A(2) of the Gas Act 1986.
Green Gas Tariff	A product offered by a Gas Supplier whereby all or a portion of the Green Gas consumption of End-Use Consumers signed up to that tariff is matched to RGGOs that have been retired and allocated to that tariff.
IGT	Independent Gas Transporter.
Mass Balance	Mass Balance is a chain of custody where an EAC is linked to the physical product. It is defined by various government and non-governmental guidance documents. Scheme Participants should pay due regard to those documents, for example the Renewable Transport Fuel Obligation Process Guidance published by the UK Government.
NTS	National Transmission System. The high pressure gas network which transports gas from the entry terminals to gas distribution networks, or directly to power stations and other large industrial users.
Oversight Panel	a panel comprising representatives of Scheme Participants, together with representatives of other stakeholders including consumer and environmental bodies, as appointed by the Scheme Administrator or invited by the Panel. It is chaired by a person independent of the Scheme.
Production Declaration	Declarations by Gas Producers regarding the amount of Green Gas they have injected into a Distribution Network based on the volume and calorific value of Green Gas injected.
REAL	Renewable Energy Assurance Limited, a wholly-owned subsidiary company of the Renewable Energy Association.
Registration Database	the information technology system used to run the Scheme. It keeps a record of the issue of RGGOs, their transfer between Gas Producers and Account Holders and their retirement or expiry. Gas Producers and Account Holders are provided with secure access to areas of the database that are relevant to their participation in the Scheme.
Retirement Request	a request by an Account Holder to retire a given number of RGGOs and generate a Retirement Statement
Retirement Statement	an electronic file generated automatically by the Registration Database on receipt of a Retirement Request. The statement contains details of the RGGOs and in relation to the Green Gas, the injection date, the technology/feedstock type and its location, the amount, CO₂ emissions and the name of the Gas Producer as well as the details of the beneficiary of the RGGOs being an End-Use Consumer or Green Gas Tariff.
RGGO	a Renewable Gas Guarantee of Origin issued by the Registration Database for each kWh of Green Gas registered on the Scheme, where evidence has been provided of its injection into a Distribution Network.
RHI	the Renewable Heat Incentive, a UK government scheme providing financial support in respect of the generation of heat from renewable sources or any other Government financial incentive scheme to promote renewable heat which confers pecuniary benefit on a Gas Producer, whether or not currently in existence, flowing from the use of Green Gas to provide heating.
RTFO	Renewable Transport Fuel Obligation
Scheme	the Green Gas Certification Scheme.
Scheme Administrator	REAL
Scheme Participant	a Gas Producer or Account Holder who is registered to participate in the Scheme and has access to a secure area of the Registration Database.
Scheme Rules	the rules governing the Scheme.
Scheme Website	www.greengas.org.uk, or any other website which the Scheme Administrator may establish.
Transfer Request	a request made via the secure area of the Registration Database by a Gas Producer or Account Holder to transfer RGGOs to an Account Holder participating in the Scheme. Requests can be accepted or rejected by the receiving party.
UNC	Uniform Network Code

Founder Partners and Associate Members: