Emissions reporting

Green Gas Certificates

Companies wishing to evidence their use of biomethane delivered through the gas grid can purchase a Green Gas Certification Scheme (GGCS) Green Gas Certificate which lists a quantity of Renewable Gas Guarantees of Origin (RGGOs).

A GGCS Certificate identifies the organisation it names as the owner of Renewable Gas Guarantees of Origin (RGGOs) listed on it and provides evidence of their green gas use in kWh units.

Certificates can be validated on the GGCS website here.

This page provides information on how greenhouse gas emissions from the combustion of biomethane delivered through the grid (as evidenced by a GGCS Green Gas Certificate) may be accounted for within the GHG Protocol methodology.

Auditors making an assessment of an organisations GHG emissions relating to biomethane use should consult the available guidance on role of green gas certificates, and may wish to use the information provided on this page.  

The Greenhouse Gas Protocol

The Greenhouse Gas (GHG) Protocol, developed by the World Resources Institute (WRI) and the World Business Council on Sustainable Development (WBCSD), sets a global standard for how to measure, manage, and report greenhouse gas emissions.

Hundreds of organisations around the world use the GHG Protocol standards and tools to manage and report their emissions. For more information please visit the GHG Protocol website - http://www.ghgprotocol.org/

The GGCS commissioned Ecofys in 2015 to review the role of Green Gas Certificates across a number of areas, including  their potential to be used under the GHG Protocol, following major changes to the Protocol’s guidance in January 2015. A summary of the key findings in this area are reproduced in this note. The full Ecofys report is available on request.

Following consultation with the GHG Protocol team, GGCS Green Gas Certificates can be used to evidence the use of biomethane against an organisation’s Scope 1 emissions (see section below for further detail and our press release here which provides further details). In addition, the Renewable Heat Incentive’s (RHI) sustainability requirements for qualifying biomethane also allow for Scope 3 emissions to be accounted for (see section below).

The CDP issued a technical note (April 2017 – available here) confirming how Green Gas Certificates can be used when reporting Scope 1 emissions.

When reporting greenhouse gas emissions the GHG Protocol defines three scopes.

Scope 1 emissions

Scope 1 emissions are related to an organisation’s on-site fuel use or fuel use in vehicles they operate.

The GHG Protocol sets out that use of biomethane delivered through the gas grid should be reported under a site’s Scope 1 emissions and that organisations can report zero Scope 1 CO2 emissions against their biomethane consumption.

In should be noted that total Scope 1 GHG emissions for biomethane use will however not be zero as for full accuracy fugitive CH4 (methane) emissions and N2O (nitrous oxide) emissions from biomethane combustion must also be accounted for - however emissions related to these two points are typically small.

Emission factors for CH4 (methane) and N2O (nitrous oxide) from biomethane combustion can be sourced in the Government’s published GHG emission factors. The latest ‘Greenhouse Gas Conversion factors - Full set (for advanced users)’ dataset can be found here. The relevant figures are on the ‘Bioenergy’ worksheet.​

Biogenic CO2 emissions must also be accounted for under GHG Protocol rules, however these can be reported separately, outside the main emission Scopes, as a memo item in a company’s GHG report.

It is important that biomethane use, and the associated emissions calculations and claims described above, are supported by appropriate evidence. GGCS Green Gas Certificates have been shown to meet the GHG Protocol quality criteria and will provide such evidence. We recommend reading the GGCS commissioned Ecofys report mentioned above for more information on this subject.

The GGCS has put in place the appropriate safeguards against double counting within the biomethane market and allows the validation of ownership of RGGOs listed on a Certificate.

Scope 2 emissions

Scope 2 emissions are generally related to consumption of electricity generated offsite.

On-site or in-vehicle biomethane use is unrelated to the reporting of Scope 2 emissions.

Scope 3 emissions

Scope 3 emissions cover all indirect emissions due to the activities of an organisation. In the case of biomethane consumption the indirect emissions are related to the lifecycle greenhouse gas emissions arising from the production process of that biomethane.

All of the biomethane registered with the GGCS to date has been supported by the Renewable Heat Incentive (RHI), which has a set of sustainability criteria that requires that injected biomethane must deliver a 60% greenhouse gas (GHG) saving over the European heat average.

This means that that biomethane production must have lifecycle greenhouse gas emissions of less than or equal to 34.8 gCO2eq/megajoule (MJ) of biomethane (measured as the net calorific value). This is equivalent to 125.28g CO2eq/kWh.

This is the figure referenced on GGCS Green Gas Certificates and can be used as a default value for Scope 3 reporting. In practice the actual figure may be lower and may be available from the biomethane producer directly.

More information on the RHI sustainability criteria and how the CO2 figure is calculated can be found by following the links below.

  1. DECC RHI sustainability note:
  1. Ofgem non-domestic RHI sustainability guidance (see paragraph 5.2):

Biomethane producers are required to self-report to Ofgem each quarter on the sustainability characteristics of the gas they have injected into the grid. This information is retrospectively audited by a third party on an annual basis to provide assurances of the validity of these calculations.

Founder partners:
British Gas
Thames Water
Milton Keynes Council
National Grid
Bio Group
CNG Services Ltd