Gas consumers who are allocated RGGOs via a Cancellation Statement may seek to make specific claims related to the Greenhouse Gas emissions resulting from their gas use.

There are various government and non-governmental reporting standards and disclosure systems for how these claims can be made and shown within an organisation's carbon reporting.

The GGCS does not determine the validity of these claims, which is the role of auditors, government regulators, or reporting schemes that consumers are subject to, such as the UK Environment Agency, Science Based Target Initiative, the GRI, or the CDP. Each consumer will have a different set of stakeholders and circumstances which will determine the type of claims that may be valid. To support consumers in this process the GGCS:

• has produced a number of guidance documents (available here) to help market participants and consumers navigate the various schemes and systems in use.
• updates our news section with information on developments in reporting rules for biomethane within the GHGP, SBTi, and other areas.

The emission factors published by the UK government here are also an important data set for UK based consumers.  

Understanding Scope 1, 2, and 3 emissions

The emissions resulting from the combustion of gas in a company’s equipment e.g. an onsite boiler, are considered to be Scope 1 emissions.

The relevant reporting methodology (e.g. GHGP) determines what those emissions are e.g. whether a valid claim is made based on RGGO use, if those emissions are biogenic or rated as zero, and if a dual reporting approach is used.
Emissions resulting from the production of gas (as recorded on a RGGO) will be the Scope 3 emissions of a gas consumer.

Consumers should be aware that any GHG values related to the production of green gas are calculated against the lower calorific value of a green gas, whereas the kWh represented by the RGGOs are the higher calorific value of the green gas. This discrepancy has arisen because of the historic practices within GHG calculations and the gas industry. Using the lower calorific value within GHG calculations ensures a conservative approach is taken to the level of GHG savings that are being made.

Calorific values are sometimes referred to as the “heating” value of a fuel or the Gross or Net measurement of its energy content. The UK government publishes figures on the Gross and Net energy values of all types of fuel here.

Scope 2 emissions only ever relate to electricity consumed. Unless a consumer is importing electricity that was produced by the combustion of biomethane offsite (as based on a RGGO claim), then Scope 2 emissions are not relevant to RGGO use.

Sustainability Criteria

GGCS Cancellation Statements will, either in the text at the bottom or within the main data fields, provide information on specific Sustainability criteria that have been met, that are either contained within a subsidy scheme e.g. NDRHI, or a standalone scheme e.g. naturemade. These criteria may include GHG thresholds and criteria on other topics e.g. land use for crop growth.

GGCS is not involved in certifying whether those criteria have been met e.g. conducting onsite audits of producers. Rather, we receive third party evidence that they have e.g. we are sent producer's NDRHI compliance reports that they produce for Ofgem.

Non-Domestic Renewable Heat Incentive (NDRHI)

The most common criteria in use are those within the Non-Domestic Renewable Heat Incentive (NDRHI) operated by the UK government. The key aspect of these criteria is that the lifecycle emissions associated with the production of biomethane, up until the point of injection to the grid, are no more than 125.28 gCO2 equivalent per kWh. Note that this value is equal to the same value stated as “kgCO2 equivalent per MWh” which is the metric used on RGGOs issued after August 9th 2024.

Where products/co-products and residues are used, then an actual calculation must be made. Where wastes are used then the producer is deemed to have met this threshold.

The capture of carbon dioxide (CO2) during the biogas-to-biomethane upgrading process is counted as a negative value within the lifecycle emissions calculation (lowering the value). This methodology does not require that the CO2 is stored and the most widespread use of this CO2 is currently in the food and drink industry.

More information the “Non-Domestic RHI Sustainability Self-Reporting Guidance” can be accessed via Ofgem’s website.

Green Gas Support Scheme (GGSS)

The GGSS is the successor to the UK government NDRHI subsidy scheme for biomethane injection. It has been open to applicants since 30 November 2021.

Under its rules, the lifecycle emissions associated with the production of biomethane, up to the point of grid injection, must be no more than 86.4 gCO2 equivalent per kWh. Note that this value is equal to the value stated as “kgCO2 equivalent per MWh” which is the metric used on RGGOs issued after August 9th 2024.

The lifecycle GHG emissions for individual feedstocks (including wastes) must be calculated, and then averaged across the total biomethane volume, to provide the overall lifecycle emissions for a quarter of biomethane production.
It is therefore possible to combine a higher GHG intensity product/co-product feedstock with a low emission Waste or Residue in order to meet the threshold.

For more details on how batches can be mixed and its impact on RGGO labelling, please consult Page 15, Section 4.5 of “GGCS Guidance Document 1 – Producer Guide”, which is available here: https://www.greengas.org.uk/news/ggcs-guidance-documents.

More information on the Sustainability Requirements of the GGSS can be found in Ofgem’s “Green Gas Support Scheme Guidance” document, available on Ofgem’s website.

Consumers should be aware that:

• the capture of carbon dioxide (CO2) during the biogas-to-biomethane upgrading process is counted as a negative value within the lifecycle emissions calculation (lowering the value). This methodology does not require that the CO2 is stored and the most widespread use of this CO2 is currently in the food and drink industry.
  
  
• the use of manure as a feedstock results in a significant negative value in the lifecycle emissions calculation (lowering the value). This is based on counterfactual savings of its use in a biomethane production process vs open storage of manure where methane would be released to the atmosphere. This type of counterfactual GHG value is not valid in Scope 1, 2, or 3 according to the GHG Protocol methodology and consumers should be aware of this discrepancy.

International Carbon and Sustainability Certification (ISCC)

Gas Producers may choose to become certified under the ISCC System of which there is more information on their website. If so, then they will be able to generate Proof of Sustainability (PoS) documents which will display calculated emissions factors.

The GGCS has a compliance process to guard against double counting between our RGGOs and ISCC PoS – see GGCS Guidance Document 19 - Interaction of GGCS and ISCC - here.

A Gas Producer’s ISCC Certification is outside the scope of the GGCS; however, where we are confident that the GHG values calculated as part of that Certification are accurate, they may be included in our RGGOs alongside high level details of a producer's certification, for which the Producer is solely responsible (see details on our RGGO data labels here).

naturemade star

The “naturemade star” sustainability criteria have been developed by the Association for Environmentally Sound Energy (VUE) in Switzerland. The criteria cover the entire process, from the production and delivery of substrates, to feeding the biomethane into the grid. More details can be found here.

No Sustainability Criteria Met

Where RGGOs are imported from registries outside the UK it is possible that neither the NDRHI nor the ISCC Sustainability Criteria will have been met; however, the GGCS will have taken steps to assure ourselves that the gas meets our definition of a Green Gas within our Scheme Rules.