Biomethane – A Sustainable Alternative to Fossil Fuels

Biomethane is a popular renewable fuel which is finding rapid acceptance across the world. Biomethane, the upgraded form of biogas, is obtained by removing carbon dioxide, hydrogen sulphide and water vapours from raw biogas. Biomethane is less corrosive than biogas, due to the absence of CO2 and sulphur, which makes it highly suitable as a vehicle fuel. There are two main types of biomethane – liquified biomethane and compressed biomethane. Both of these forms make it suitable for biomethane to be stored for a long period and transported over long distances.

Liquified Biomethane (LBM)

Liquified biomethane, also known as bio-LNG, is the liquid form of biomethane can be liquefied. When biomethane is used as a vehicle fuel, it is recommended to convert into liquid biogas.  At atmospheric pressure, liquified biomethane is 600 times more space efficient than biogas. A key benefit of LBM is that it can transported easily over long distances in insulated tanker trucks meant for transportation of cryogenic fluids.

Compressed Biomethane Gas (CBG)

Like natural gas, biomethane can be compressed to produce compressed biomethane gas. Compressed biomethane can be stored in steel cylinders meant for storage of commercial gases. Storage facilities for CBG should be equipped fitted with safety devices, pressure relief valves. Compressed biomethane can be used for electricity and heat generation, as a transportation fuel.

Uses of Biomethane

Biomethane is a green and sustainable alternative to fossil fuels. Compared to biogas, biomethane is more versatile and efficient in its applications. Biomethane can be injected directly into the existing natural gas grid which helps consumers to make a smooth transition to a renewable fuel.

Biomethane van used to generate electricity and heat in small decentralized plants or large CHP plants. In addition, biomethane is being used in light passenger vehicles and heavy vehicles. Injected biomethane can be used at any ratio with natural gas as vehicle fuel. The maritime and rail transport sector is also showing increasing interest in biomethane as a sustainable alternative to diesel.

Biomethane-to-Grid

Biomethane can be injected into the natural gas grid to substitute natural gas. It can also be compressed and fuelled via a pumping station at the production facility. On compression to the pipeline pressure, biomethane can be injected and distributed through the natural gas grid. Notably, grid access is guaranteed for all biomethane suppliers in most of the EU countries.

An important benefit of grid access for biomethane distribution is the linkage between the biomethane production facility, usually located in rural areas, and densely populated urban centres which enables the biomethane to reach new customers

The main hurdle in biomethane-to-grid project is the high biogas upgrading cost and the availability of grid connection. The biomethane production and upgrading facility should ideally be located close to the natural gas grid to make the project financially viable.

Many European nations have introduced certification systems for biogas injection into the natural gas grid. These certification systems recommends the limits for undesirable components like sulphur, oxygen, particles and water dew point, in order to avoid contamination of the gas grid or the end users.