Green Gas Support Scheme and Green Gas Levy

Commissioning Deadline

On 16 October 2026 the Department for Energy Security and Net Zero (DESNZ) extended the commissioning and stage 3 application deadline to 31 March 2030. The deadline for submission of new stage 1 applications remains 31 March 2028.  

Applicants with a commissioning date after 31 March 2028 will have a shorter tariff lifetime, eligible to receive periodic payments until 31 March 2043 at the latest.  

If a Stage 1 application was made on or after 10 December 2025, applicants are now able to amend their expected commissioning date to a date no later than 31 March 2030, and can do so by emailing GGSS.app@ofgem.gov.uk.  

Inflation Forecasts and Production Factors

Updated Inflation forecasts for the financial year 2026 to 2027 have also been announced by DESNZ, which are now effective as of 1 April 2026. Any Tariff Guarantee applications made on or after 1April 2026 will be subject to the new inflation forecasts.    

Production factors for the financial year 2026 to 2027 will remain unchanged.  

Annual Tariff Review

DESNZ on 1September 2025 confirmed the results of the GGSS Annual Tariff Review 2025. Following the review of tariffs and thresholds, the Secretary of State has decided that GGSS tariffs and degression thresholds will remain unchanged on 1 October 2025. These tariffs and degression thresholds remain in place subject to any future tariff review by DESNZ. The GGSS tariffs are set out in the Green Gas Support Scheme tariff table. 

The Application Budget cap is designed to provide a cap against which applications to the scheme will be checked to ensure that there is available budget for them to register and receive payments under the scheme based on their estimated production. 

The Department for Energy Security and Net Zero (DESNZ) have confirmed that the GGSS Application Budget cap for the financial year 2026 to 2027 will remain at £124.9 million. This budget cap was announced on 17 December 2025 and is in effect from 1 April 2026.   

This allocation aligns with DESNZ's previous budget commitment. The Application Budget (AB) budget caps, which control the budget for applicants and the total value of funding that can be allocated to participants, remain unchanged. 

Summary of applications, tariff guarantees and registrations

Allocated and remaining budget for each financial year

This information represents the budget queue and granted Tariff Guarantees as of 5 October 2026. It is subject to change based on ongoing queue movement and should not be used for the purpose of making commercial decisions; it is for information only. From 8 June 2026 these tables will be updated weekly.  

Please note that there may be recent applications currently under review which have not yet been allocated budget or entered the budget queue. Any such applications may therefore not be reflected in the Budget allocated, Remaining budget available figures or Total indicative budget queue in the above. The figures presented are indicative and may be subject to change on a daily basis 

What happens if the budget is fully allocated

The Application Budget cap has been reached, meaning there is insufficient budget available to approve new applications. We are therefore operating an application budget queue. 

Applications will be processed in the order they applied should additional budget become available either through other applications withdrawing or being rejected or through an increase in budget by the Secretary of State each financial year. 

Later applications with a smaller capacity may be processed should there be sufficient budget available for that application. Please see the DESNZ Green Gas Support Scheme Budget Management guidance for more details of the budget caps. 

Please note we will not issue a Provisional Tariff Guarantee Notice if it were to cause the budget cap to be exceeded. Should an applicant choose to withdraw with the intention to re-apply, this is at their own risk. Re-entry to the scheme is not guaranteed, and is subject to available budget and the scheme eligibility criteria at the time of reapplication. Please see our guidance for details on how we administer the budget queue. 

The GGSS is designed to support the deployment of new anaerobic digestion (AD) biomethane plants to increase the proportion of green gas in the gas grid. 

Regular support payments will be provided to registered biomethane producers based on the volume of eligible biomethane, produced from AD, that they inject into the gas grid. 

If you are a producer of biomethane, or plan on producing biomethane in the future, you may be eligible to apply for the GGSS. 

All prospective applicants should read our GGSS Guidance for full details on the scheme’s eligibility requirements. 

Before applying it is essential that potential applicants familiarise themselves with the requirements of the GGSS Regulations, in particular the GGSS eligibility criteria and ongoing obligations as set out in the scheme regulations. These can be found in the GGSS Guidance. In addition, potential applicants may wish to refer to the table above indicating available budget. There are three stages to the application process. 

Stage 1: Prospective scheme participants must first apply for a tariff guarantee. This will enable them to secure a fixed tariff rate before their installation is fully commissioned and registered on the scheme. The deadline for a stage 1 application is 31 March 2028. 

To apply for stage 1, the plant must be sufficiently developed in order to be able to provide key details such as: 

• evidence of a connection agreement 
• planning permission details 
• expected maximum initial capacity 
• expected volume of eligible biomethane to be injected each year.  

Stage 2: After Stage 1 has been approved, applicants will be required to provide evidence of financial close within three weeks. This should demonstrate that funds are available to cover the complete construction and commissioning of the proposed project, and that these funds are formally committed to the project. See our GGSS Guidance (Stage 1: Initial Application) for more information and a full list of information required. If the Stage 2 application is successful, we will issue a tariff guarantee. 

Stage 3: If issued with a tariff guarantee, the applicant can apply for GGSS registration once the plant has been commissioned and has started to inject biomethane. The plant must be commissioned by the commissioning date stated when the tariff guarantee was applied for plus a 182-day grace period, or by the relevant commissioning and stage 3 application deadline in place at the time of making the application.  

Having a tariff guarantee does not guarantee that full registration will be granted, and there are circumstances in which we may revoke a tariff guarantee These are given in our GGSS Guidance. 

A properly made application is one where all the required information has been provided to a suitable standard to enable us to make a decision on the application. In some cases, we may need to contact applicants for further information to enable us to verify eligibility. When requesting further information, we will apply a deadline, usually five working days. If the information is not provided within the deadline specified, we will reject the application and the budget will be reallocated. Should that applicant wish to re-apply to the scheme, they would need to submit a new stage 1 application and would join the back of the budget allocation queue. 

Applications to the scheme must be made online using the GGSS Portal.   

The first step will be to create a user account. 

If the application is being made on behalf of an organisation, the applicant will need to register that organisation after the person making the application has set up their own user account. 

We will require a letter of authorisation (LOA) to be completed to confirm who has been given legal authority to act on behalf of the applicant for the purposes of the GGSS.   

Applicants for Stage 3 registration will need to complete a Fuel Measurement and Sampling Questionnaire and submit this as part of their application. 

Additional users may be added to the GGSS account in order to be able to provide information in relation to the application but will not be able to submit an application. 

The GGSS tariffs are set out in the Green Gas Support Scheme tariff table. For current tariff rates, see the tariff table page. 

Each year, by 15 March, 15 June, 15 September and 15 December, we will publish the initial tariff rate that will apply where a tariff start date falls within the following quarter. Tariff rates are set by the Department for Energy Security and Net Zero, see their website for more information. 

Refer to the GGSS Guidance document for more detailed information and guidance before making an application. The comprehensive guidance includes more details relating to: 

• Eligibility criteria 
• How to apply 
• Ongoing obligations