What is renewable gas?
Renewable gas, or green gas, is a clean, low-carbon, sustainable fuel source which is produced from sustainable organic materials, and which can upgraded to biomethane for injection into the existing natural gas pipeline network. It can be used in heating, electricity generation and in transport. In Ireland, the initial sources for those organic materials will be wastes and residues such as animal slurry and food waste. Over time, energy crops such as grass, willow and seaweed can be introduced. Renewable gas can be produced by anaerobic digestion, gasification and power to gas technologies.
Why do we need a certification scheme?
Certification enables sustainably produced biomethane to be injected into the natural gas network at or close to its point of production and to be used by any Irish gas consumer connected to the network. The certification blueprint developed by this project will provide:
- A reliable means of tracing renewable gas from the consumer to the producer, and even back to the substrate used to produce the gas;
- A systematic approach to determining the sustainability of biogas produced in Ireland;
- Confidence to the consumer that gas delivered is renewable;
- A means of determining national renewable gas consumption and associated emissions;
- A scheme tailored to Irish conditions and requirements that will support the growth of a market for sustainable biogas in Ireland.
How does certification work?
The GreenGasCert project team have delivered a blueprint for a certification scheme for Ireland. It includes a methodology and tool for calculation of greenhouse gas emissions associated with biogas, a proposal for the assessment of the sustainability criteria associated with the gas, and a blueprint for the operation of a biogas registry.
GHG calculation methodology
The first part of the certification is the calculation of the emissions associated with the biogas. The approach covers the complete lifecycle from the cultivation of the feedstocks used for biogas production right through to end-use of the gas and is in line with the requirements of the Renewable Energy Directive. The formula shown below adds up all the emissions associated with each process step and subtracts any emissions savings from, for example, improved agricultural management or from carbon capture and storage. The result is an emissions value per unit of gas. The methodology is supported by a calculation tool.
The certification process enables us to attach sustainability criteria to the gas.
At the core we have some mandatory criteria from the Renewable Energy Directive that must be met, such as protection of land with high carbon stocks or land with high biodiversity value as well as the assessment of whether mandatory thresholds for greenhouse gas reduction have been met.
But we can add additional criteria that assess the wider sustainability; for instance environmental sustainability indicators for water or air quality or economic sustainability indicators such as employment, local prosperity and contribution to the rural economy.
the biogas registry provides the secure data platform for the registering and trading of renewable gas. It provides reliable information on the production and consumption of each unit of gas traded. A brief overview of the registry process is as follows:
Step 1: Once the registry is established, producers, trading companies and also energy suppliers can enrol in the registry.
Step 2: The produced and injected green gas amounts have to be registered based on metered data from the grid operator. Registry certificates for the metered amount are assigned to the producer. The software has to ensure that only the registered and verified amount is processed.
Step 3: Certificates can now be traded between account holders. Users can split certificates into smaller amounts and transfer them to other account holders.
Step 4: The process cycle ends with the cancellation of the registry certificate. This can be done by account holders when they want to use their certificate for a particular purpose, for instance as proof of savings in voluntary disclosure scheme or perhaps to qualify for a support scheme. The end-use application of the gas can be recorded at this stage.