Biomethane

Biomethane is a methane made from biogenic feedstock.

The first step is to produce biogas by putting energy sources such as agricultural wastes, food processing residues and crops into an Anaerobic Digestion (AD) process, where they are broken down by bacteria into carbon dioxide and methane gas.

This biogas is “upgraded” to biomethane by separating the CO2 from the methane and ensuring it meets the necessary quality and purity standards.

Biomethane can be injected in the gas grid and used in the same way as natural gas, meaning that the existing infrastructure does not need to be replaced.

The amount of CO2 and other greenhouse gases that are emitted during the biomethane production varies according to the feedstock and production process. Renewable gas certificates will often provide information to consumers so those emissions are known and can be reported.

Biomethane producers aim to limit production emissions by maximising the use of residues and wastes and ensuring their plant is efficient.

Production that uses animal manures and sewage can claim to have saved a large amount of carbon that would have released into the atmosphere if those feedstocks had been left unused.

Carbon emitted from the combustion of biomethane is “biogenic”, having been recently captured by plants that are either processed directly into biomethane or are the starting point for a process where the waste or residue is used as a feedstock. It therefore does not add to atmospheric carbon in the same way as fossil fuel.

Within Europe sustainability requirements (such as the origin of the feedstock) are defined by legislation. If the biomethane is produced in compliance with these requirements it can be considered sustainable.

As well as being renewable and potentially sustainable, the production of biomethane has also other advantages for society and the environment. For instance:

• Digestate (a by-product of biomethane) can be used as a natural fertilizer.

• During the upgrading of biogas CO2 can be captured, making the production even carbon negative. Moreover, this biogenic CO2 can be used in other sectors, such producing Sustainable Aviation Fuels.

• Biomethane production creates jobs in rural areas.

Renewable (green) hydrogen

Hydrogen is a colourless, odourless gas that is the lightest and most abundant chemical element in the universe. It can be used in a wide range of applications, such as transport or fertiliser production.

Renewable hydrogen, also known as green hydrogen, is produced using renewable energy sources such as wind, solar, or hydroelectric power. The process typically involves electrolysis, where an electric current is used to split water into hydrogen and oxygen. Detailed sustainability requirements are set at the EU level before hydrogen can be considered a Renewable Fuel of Non-Biological Origin (RFNBO). These requirements focus on additionality and temporal and geographic correlation of the electricity that is used to produce the hydrogen.

Renewable hydrogen can be used to produce other renewable gases mentioned in the ‘Other renewable gases’ box.

The amount of renewable hydrogen currently available is limited compared to the amount of biomethane. But production and demand is expected to increase in the future.

Other renewable gases

As well as hydrogen and biomethane, other renewable gases include e-methane (or synthetic natural gas), ammonia and methanol.

They can be produced via various chemical processes with sustainable biomass, hydrogen and biogenic or fossil CO2 as the key feedstocks.

Each of these renewable gases has its own applications and advantages. If the feedstocks are produced sustainably they can be considered sustainable in Europe according to the RFNBO criteria.