Guarantees of Origin

Long-term RGGO offtake mandates that deliver revenue certainty for AD operators and verified supply for corporate buyers.

The Certificate

When biomethane produced by an AD plant is injected into the UK gas grid, each kilowatt hour (kWh) generates a Renewable Gas Guarantee of Origin (RGGO). RGGOs confirm the renewable and sustainable origin of the biomethane injected. These certificates are administered by the Green Gas Certification Scheme (GGCS) under Ofgem oversight, and are typically traded in megawatt hour (MWh) volumes.

For AD plants operating in the European Union, the equivalent instrument is the Guarantee of Origin (GO), governed by the EU Renewable Energy Directive.

GreenOas certification scheme logo, with the words 'GreenOas' in large green font and 'CERTIFICATION SCHEME' in smaller gray font underneath.

  • Not all RGGOs carry the same value. The certification standard behind the certificate determines both its market price and its climate credentials. 

    RGGOs verified to the International Sustainability and Carbon Certification (ISCC) standard carry enhanced traceability, feedstock verification, and sustainability attributes. These ISCC Waste-verified RGGOs command the highest prices because they represent the most credible, auditable, and impactful form of renewable gas certification available. The feedstock is genuinely circular, the sustainability credentials are independently verified, and the lifecycle emissions profile is significantly stronger than crop-based alternatives.

    RGGOs can also be verified under ISCC standards using crop-based or mixed feedstocks, or issued under the standard GGCS scheme without ISCC verification. Each tier serves a purpose in the market. For corporate buyers with serious decarbonisation commitments ISCC Waste-verified RGGOs are the benchmark.

The Problem Kerkap Solves

  • Many AD operators produce ISCC-aligned RGGOs but lack the commercial relationships, sustainability market expertise, or dedicated resource to structure long-term supply agreements. Most sell through short-term or spot arrangements, leaving revenue exposed to a market that has proved volatile. In doing so, AD operators sacrifice both revenue predictability and the long-term value of their output.

  • For corporate offtakers, retiring RGGOs is a verified and auditable way to reduce reported scope 1 emissions from gas consumption.

    Each MWh of RGGOs equates to approximately 0.2 tCO2e, based on DESNZ UK Government GHG Conversion Factors (2024). For a gas consumer retiring 50,000 MWh of RGGOs, that represents roughly 10,000 tCO2e per year, a material reduction for any company with net-zero obligations.

    ISCC-verified RGGOs with Proof of Sustainability documentation also satisfy the disclosure requirements of major reporting frameworks including CSRD (Corporate Sustainability Reporting Directive) and TCFD (Task Force on Climate-related Financial Disclosures). For buyers navigating increasingly rigorous ESG reporting, verified RGGOs are not just an emissions tool, they are an audit and compliance tool.

How we work

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How We Work

Kerkap acts as the commercial agent between AD plant operators and corporate off-takers.

We do not purchase, hold, or take financial exposure to certificates at any point. Certificates remain the property of the AD operator until transferred directly to the buyer's GGCS account.

Under a formal mandate agreement, we take on the commercial role of finding the right buyer for the operator's certificated output. We match buyers and operator's against volume, duration, and pricing requirements. We then structure a multi-year RGGO supply agreement that works for both sides. Our target contract period is three years or longer, giving AD operators revenue predictability. Corporate buyers get the verified, traceable supply they need to support their scope 1 net-zero commitments. Kerkap brings the two together.

Kerkap earns an arrangement fee, based on the value of the contract, for handling all aspects of the transaction.

Scale & Emission Factors

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Scale & Emission Factor Reference

1 RGGO Certificate = 1kWh

RGGOs are sold and priced in MWh bundles

1000 RGGO Certificates = 1MWh = ~ 0.2 tCO2e scope 1 reduction

~1.0 tCO2e scope 1 reduction = 5 MWh = 5000 RGGO Certificates

Source: DESNZ (2024), UK Government Greenhouse Gas Conversion Factors for Company Reporting. Natural gas emission factor: 0.18293 kgCO2e/kWh (gross CV).